Firmware2/Marlin/src/module/planner.cpp

/**
 * Marlin 3D Printer Firmware
 * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

/**
 * planner.cpp
 *
 * Buffer movement commands and manage the acceleration profile plan
 *
 * Derived from Grbl
 * Copyright (c) 2009-2011 Simen Svale Skogsrud
 *
 * The ring buffer implementation gleaned from the wiring_serial library by David A. Mellis.
 *
 *
 * Reasoning behind the mathematics in this module (in the key of 'Mathematica'):
 *
 * s == speed, a == acceleration, t == time, d == distance
 *
 * Basic definitions:
 *   Speed[s_, a_, t_] := s + (a*t)
 *   Travel[s_, a_, t_] := Integrate[Speed[s, a, t], t]
 *
 * Distance to reach a specific speed with a constant acceleration:
 *   Solve[{Speed[s, a, t] == m, Travel[s, a, t] == d}, d, t]
 *   d -> (m^2 - s^2)/(2 a) --> estimate_acceleration_distance()
 *
 * Speed after a given distance of travel with constant acceleration:
 *   Solve[{Speed[s, a, t] == m, Travel[s, a, t] == d}, m, t]
 *   m -> Sqrt[2 a d + s^2]
 *
 * DestinationSpeed[s_, a_, d_] := Sqrt[2 a d + s^2]
 *
 * When to start braking (di) to reach a specified destination speed (s2) after accelerating
 * from initial speed s1 without ever stopping at a plateau:
 *   Solve[{DestinationSpeed[s1, a, di] == DestinationSpeed[s2, a, d - di]}, di]
 *   di -> (2 a d - s1^2 + s2^2)/(4 a) --> intersection_distance()
 *
 * IntersectionDistance[s1_, s2_, a_, d_] := (2 a d - s1^2 + s2^2)/(4 a)
 *
 * --
 *
 * The fast inverse function needed for Bézier interpolation for AVR
 * was designed, written and tested by Eduardo José Tagle on April/2018
 */

#include "planner.h"
#include "stepper.h"
#include "motion.h"
#include "../module/temperature.h"
#include "../lcd/ultralcd.h"
#include "../core/language.h"
#include "../gcode/parser.h"

#include "../Marlin.h"

#if HAS_LEVELING
  #include "../feature/bedlevel/bedlevel.h"
#endif

#if ENABLED(FILAMENT_WIDTH_SENSOR)
  #include "../feature/filwidth.h"
#endif

#if ENABLED(BARICUDA)
  #include "../feature/baricuda.h"
#endif

#if ENABLED(MIXING_EXTRUDER)
  #include "../feature/mixing.h"
#endif

#if ENABLED(AUTO_POWER_CONTROL)
  #include "../feature/power.h"
#endif

Planner planner;

  // public:

/**
 * A ring buffer of moves described in steps
 */
block_t Planner::block_buffer[BLOCK_BUFFER_SIZE];
volatile uint8_t Planner::block_buffer_head, // Index of the next block to be pushed
                 Planner::block_buffer_tail;

float Planner::max_feedrate_mm_s[XYZE_N], // Max speeds in mm per second
      Planner::axis_steps_per_mm[XYZE_N],
      Planner::steps_to_mm[XYZE_N];

#if ENABLED(DISTINCT_E_FACTORS)
  uint8_t Planner::last_extruder = 0;     // Respond to extruder change
#endif

int16_t Planner::flow_percentage[EXTRUDERS] = ARRAY_BY_EXTRUDERS1(100); // Extrusion factor for each extruder

float Planner::e_factor[EXTRUDERS] = ARRAY_BY_EXTRUDERS1(1.0); // The flow percentage and volumetric multiplier combine to scale E movement

#if DISABLED(NO_VOLUMETRICS)
  float Planner::filament_size[EXTRUDERS],          // diameter of filament (in millimeters), typically around 1.75 or 2.85, 0 disables the volumetric calculations for the extruder
        Planner::volumetric_area_nominal = CIRCLE_AREA((DEFAULT_NOMINAL_FILAMENT_DIA) * 0.5), // Nominal cross-sectional area
        Planner::volumetric_multiplier[EXTRUDERS];  // Reciprocal of cross-sectional area of filament (in mm^2). Pre-calculated to reduce computation in the planner
#endif

uint32_t Planner::max_acceleration_steps_per_s2[XYZE_N],
         Planner::max_acceleration_mm_per_s2[XYZE_N]; // Use M201 to override by software

uint32_t Planner::min_segment_time_us;

// Initialized by settings.load()
float Planner::min_feedrate_mm_s,
      Planner::acceleration,         // Normal acceleration mm/s^2  DEFAULT ACCELERATION for all printing moves. M204 SXXXX
      Planner::retract_acceleration, // Retract acceleration mm/s^2 filament pull-back and push-forward while standing still in the other axes M204 TXXXX
      Planner::travel_acceleration,  // Travel acceleration mm/s^2  DEFAULT ACCELERATION for all NON printing moves. M204 MXXXX
      Planner::max_jerk[XYZE],       // The largest speed change requiring no acceleration
      Planner::min_travel_feedrate_mm_s;

#if HAS_LEVELING
  bool Planner::leveling_active = false; // Flag that auto bed leveling is enabled
  #if ABL_PLANAR
    matrix_3x3 Planner::bed_level_matrix; // Transform to compensate for bed level
  #endif
  #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
    float Planner::z_fade_height,      // Initialized by settings.load()
          Planner::inverse_z_fade_height,
          Planner::last_fade_z;
  #endif
#else
  constexpr bool Planner::leveling_active;
#endif

#if ENABLED(SKEW_CORRECTION)
  #if ENABLED(SKEW_CORRECTION_GCODE)
    float Planner::xy_skew_factor;
  #else
    constexpr float Planner::xy_skew_factor;
  #endif
  #if ENABLED(SKEW_CORRECTION_FOR_Z) && ENABLED(SKEW_CORRECTION_GCODE)
    float Planner::xz_skew_factor, Planner::yz_skew_factor;
  #else
    constexpr float Planner::xz_skew_factor, Planner::yz_skew_factor;
  #endif
#endif

#if ENABLED(AUTOTEMP)
  float Planner::autotemp_max = 250,
        Planner::autotemp_min = 210,
        Planner::autotemp_factor = 0.1;
  bool Planner::autotemp_enabled = false;
#endif

// private:

int32_t Planner::position[NUM_AXIS] = { 0 };

uint32_t Planner::cutoff_long;

float Planner::previous_speed[NUM_AXIS],
      Planner::previous_nominal_speed;

#if ENABLED(DISABLE_INACTIVE_EXTRUDER)
  uint8_t Planner::g_uc_extruder_last_move[EXTRUDERS] = { 0 };
#endif

#ifdef XY_FREQUENCY_LIMIT
  // Old direction bits. Used for speed calculations
  unsigned char Planner::old_direction_bits = 0;
  // Segment times (in µs). Used for speed calculations
  uint32_t Planner::axis_segment_time_us[2][3] = { { MAX_FREQ_TIME_US + 1, 0, 0 }, { MAX_FREQ_TIME_US + 1, 0, 0 } };
#endif

#if ENABLED(LIN_ADVANCE)
  float Planner::extruder_advance_K; // Initialized by settings.load()
#endif

#if HAS_POSITION_FLOAT
  float Planner::position_float[XYZE]; // Needed for accurate maths. Steps cannot be used!
#endif

#if ENABLED(ULTRA_LCD)
  volatile uint32_t Planner::block_buffer_runtime_us = 0;
#endif

/**
 * Class and Instance Methods
 */

Planner::Planner() { init(); }

void Planner::init() {
  ZERO(position);
  #if HAS_POSITION_FLOAT
    ZERO(position_float);
  #endif
  ZERO(previous_speed);
  previous_nominal_speed = 0.0;
  #if ABL_PLANAR
    bed_level_matrix.set_to_identity();
  #endif
  clear_block_buffer();
}

#if ENABLED(BEZIER_JERK_CONTROL)

  #ifdef __AVR__
    // This routine, for AVR, returns 0x1000000 / d, but trying to get the inverse as
    //  fast as possible. A fast converging iterative Newton-Raphson method is able to
    //  reach full precision in just 1 iteration, and takes 211 cycles (worst case, mean
    //  case is less, up to 30 cycles for small divisors), instead of the 500 cycles a
    //  normal division would take.
    //
    // Inspired by the following page,
    //  https://stackoverflow.com/questions/27801397/newton-raphson-division-with-big-integers
    //
    // Suppose we want to calculate
    //  floor(2 ^ k / B)    where B is a positive integer
    // Then
    //  B must be <= 2^k, otherwise, the quotient is 0.
    //
    // The Newton - Raphson iteration for x = B / 2 ^ k yields:
    //  q[n + 1] = q[n] * (2 - q[n] * B / 2 ^ k)
    //
    // We can rearrange it as:
    //  q[n + 1] = q[n] * (2 ^ (k + 1) - q[n] * B) >> k
    //
    //  Each iteration of this kind requires only integer multiplications
    // and bit shifts.
    //  Does it converge to floor(2 ^ k / B) ?:  Not necessarily, but, in
    // the worst case, it eventually alternates between floor(2 ^ k / B)
    // and ceiling(2 ^ k / B)).
    //  So we can use some not-so-clever test to see if we are in this
    // case, and extract floor(2 ^ k / B).
    //  Lastly, a simple but important optimization for this approach is to
    // truncate multiplications (i.e.calculate only the higher bits of the
    // product) in the early iterations of the Newton - Raphson method.The
    // reason to do so, is that the results of the early iterations are far
    // from the quotient, and it doesn't matter to perform them inaccurately.
    //  Finally, we should pick a good starting value for x. Knowing how many
    // digits the divisor has, we can estimate it:
    //
    // 2^k / x = 2 ^ log2(2^k / x)
    // 2^k / x = 2 ^(log2(2^k)-log2(x))
    // 2^k / x = 2 ^(k*log2(2)-log2(x))
    // 2^k / x = 2 ^ (k-log2(x))
    // 2^k / x >= 2 ^ (k-floor(log2(x)))
    // floor(log2(x)) simply is the index of the most significant bit set.
    //
    //  If we could improve this estimation even further, then the number of
    // iterations can be dropped quite a bit, thus saving valuable execution time.
    //  The paper "Software Integer Division" by Thomas L.Rodeheffer, Microsoft
    // Research, Silicon Valley,August 26, 2008, that is available at
    // https://www.microsoft.com/en-us/research/wp-content/uploads/2008/08/tr-2008-141.pdf
    // suggests , for its integer division algorithm, that using a table to supply the
    // first 8 bits of precision, and due to the quadratic convergence nature of the
    // Newton-Raphon iteration, then just 2 iterations should be enough to get
    // maximum precision of the division.
    //  If we precompute values of inverses for small denominator values, then
    // just one Newton-Raphson iteration is enough to reach full precision
    //  We will use the top 9 bits of the denominator as index.
    //
    //  The AVR assembly function is implementing the following C code, included
    // here as reference:
    //
    // uint32_t get_period_inverse(uint32_t d) {
    //  static const uint8_t inv_tab[256] = {
    //    255,253,252,250,248,246,244,242,240,238,236,234,233,231,229,227,
    //    225,224,222,220,218,217,215,213,212,210,208,207,205,203,202,200,
    //    199,197,195,194,192,191,189,188,186,185,183,182,180,179,178,176,
    //    175,173,172,170,169,168,166,165,164,162,161,160,158,157,156,154,
    //    153,152,151,149,148,147,146,144,143,142,141,139,138,137,136,135,
    //    134,132,131,130,129,128,127,126,125,123,122,121,120,119,118,117,
    //    116,115,114,113,112,111,110,109,108,107,106,105,104,103,102,101,
    //    100,99,98,97,96,95,94,93,92,91,90,89,88,88,87,86,
    //    85,84,83,82,81,80,80,79,78,77,76,75,74,74,73,72,
    //    71,70,70,69,68,67,66,66,65,64,63,62,62,61,60,59,
    //    59,58,57,56,56,55,54,53,53,52,51,50,50,49,48,48,
    //    47,46,46,45,44,43,43,42,41,41,40,39,39,38,37,37,
    //    36,35,35,34,33,33,32,32,31,30,30,29,28,28,27,27,
    //    26,25,25,24,24,23,22,22,21,21,20,19,19,18,18,17,
    //    17,16,15,15,14,14,13,13,12,12,11,10,10,9,9,8,
    //    8,7,7,6,6,5,5,4,4,3,3,2,2,1,0,0
    //  };
    //
    //  // For small denominators, it is cheaper to directly store the result,
    //  //  because those denominators would require 2 Newton-Raphson iterations
    //  //  to converge to the required result precision. For bigger ones, just
    //  //  ONE Newton-Raphson iteration is enough to get maximum precision!
    //  static const uint32_t small_inv_tab[111] PROGMEM = {
    //    16777216,16777216,8388608,5592405,4194304,3355443,2796202,2396745,2097152,1864135,1677721,1525201,1398101,1290555,1198372,1118481,
    //    1048576,986895,932067,883011,838860,798915,762600,729444,699050,671088,645277,621378,599186,578524,559240,541200,
    //    524288,508400,493447,479349,466033,453438,441505,430185,419430,409200,399457,390167,381300,372827,364722,356962,
    //    349525,342392,335544,328965,322638,316551,310689,305040,299593,294337,289262,284359,279620,275036,270600,266305,
    //    262144,258111,254200,250406,246723,243148,239674,236298,233016,229824,226719,223696,220752,217885,215092,212369,
    //    209715,207126,204600,202135,199728,197379,195083,192841,190650,188508,186413,184365,182361,180400,178481,176602,
    //    174762,172960,171196,169466,167772,166111,164482,162885,161319,159783,158275,156796,155344,153919,152520
    //  };
    //
    //  // For small divisors, it is best to directly retrieve the results
    //  if (d <= 110)
    //    return pgm_read_dword(&small_inv_tab[d]);
    //
    //  // Compute initial estimation of 0x1000000/x -
    //  // Get most significant bit set on divider
    //  uint8_t idx = 0;
    //  uint32_t nr = d;
    //  if (!(nr & 0xFF0000)) {
    //    nr <<= 8;
    //    idx += 8;
    //    if (!(nr & 0xFF0000)) {
    //      nr <<= 8;
    //      idx += 8;
    //    }
    //  }
    //  if (!(nr & 0xF00000)) {
    //    nr <<= 4;
    //    idx += 4;
    //  }
    //  if (!(nr & 0xC00000)) {
    //    nr <<= 2;
    //    idx += 2;
    //  }
    //  if (!(nr & 0x800000)) {
    //    nr <<= 1;
    //    idx += 1;
    //  }
    //
    //  // Isolate top 9 bits of the denominator, to be used as index into the initial estimation table
    //  uint32_t tidx = nr >> 15;         // top 9 bits. bit8 is always set
    //  uint32_t ie = inv_tab[tidx & 0xFF] + 256; // Get the table value. bit9 is always set
    //  uint32_t x = idx <= 8 ? (ie >> (8 - idx)) : (ie << (idx - 8)); // Position the estimation at the proper place
    //
    //  // Now, refine estimation by newton-raphson. 1 iteration is enough
    //  x = uint32_t((x * uint64_t((1 << 25) - x * d)) >> 24);
    //
    //  // Estimate remainder
    //  uint32_t r = (1 << 24) - x * d;
    //
    //  // Check if we must adjust result
    //  if (r >= d) x++;
    //
    //  // x holds the proper estimation
    //  return uint32_t(x);
    // }
    //
    static uint32_t get_period_inverse(uint32_t d) {

       static const uint8_t inv_tab[256] PROGMEM = {
        255,253,252,250,248,246,244,242,240,238,236,234,233,231,229,227,
        225,224,222,220,218,217,215,213,212,210,208,207,205,203,202,200,
        199,197,195,194,192,191,189,188,186,185,183,182,180,179,178,176,
        175,173,172,170,169,168,166,165,164,162,161,160,158,157,156,154,
        153,152,151,149,148,147,146,144,143,142,141,139,138,137,136,135,
        134,132,131,130,129,128,127,126,125,123,122,121,120,119,118,117,
        116,115,114,113,112,111,110,109,108,107,106,105,104,103,102,101,
        100,99,98,97,96,95,94,93,92,91,90,89,88,88,87,86,
        85,84,83,82,81,80,80,79,78,77,76,75,74,74,73,72,
        71,70,70,69,68,67,66,66,65,64,63,62,62,61,60,59,
        59,58,57,56,56,55,54,53,53,52,51,50,50,49,48,48,
        47,46,46,45,44,43,43,42,41,41,40,39,39,38,37,37,
        36,35,35,34,33,33,32,32,31,30,30,29,28,28,27,27,
        26,25,25,24,24,23,22,22,21,21,20,19,19,18,18,17,
        17,16,15,15,14,14,13,13,12,12,11,10,10,9,9,8,
        8,7,7,6,6,5,5,4,4,3,3,2,2,1,0,0
      };

      // For small denominators, it is cheaper to directly store the result.
      //  For bigger ones, just ONE Newton-Raphson iteration is enough to get
      //  maximum precision we need
      static const uint32_t small_inv_tab[111] PROGMEM = {
        16777216,16777216,8388608,5592405,4194304,3355443,2796202,2396745,2097152,1864135,1677721,1525201,1398101,1290555,1198372,1118481,
        1048576,986895,932067,883011,838860,798915,762600,729444,699050,671088,645277,621378,599186,578524,559240,541200,
        524288,508400,493447,479349,466033,453438,441505,430185,419430,409200,399457,390167,381300,372827,364722,356962,
        349525,342392,335544,328965,322638,316551,310689,305040,299593,294337,289262,284359,279620,275036,270600,266305,
        262144,258111,254200,250406,246723,243148,239674,236298,233016,229824,226719,223696,220752,217885,215092,212369,
        209715,207126,204600,202135,199728,197379,195083,192841,190650,188508,186413,184365,182361,180400,178481,176602,
        174762,172960,171196,169466,167772,166111,164482,162885,161319,159783,158275,156796,155344,153919,152520
      };

      // For small divisors, it is best to directly retrieve the results
      if (d <= 110)
        return pgm_read_dword(&small_inv_tab[d]);

      register uint8_t r8 = d & 0xFF;
      register uint8_t r9 = (d >> 8) & 0xFF;
      register uint8_t r10 = (d >> 16) & 0xFF;
      register uint8_t r2,r3,r4,r5,r6,r7,r11,r12,r13,r14,r15,r16,r17,r18;
      register const uint8_t* ptab = inv_tab;

      __asm__ __volatile__(
        // %8:%7:%6 = interval
        // r31:r30: MUST be those registers, and they must point to the inv_tab

        A("clr %13")                       // %13 = 0

        // Now we must compute
        // result = 0xFFFFFF / d
        // %8:%7:%6 = interval
        // %16:%15:%14 = nr
        // %13 = 0

        // A plain division of 24x24 bits should take 388 cycles to complete. We will
        // use Newton-Raphson for the calculation, and will strive to get way less cycles
        // for the same result - Using C division, it takes 500cycles to complete .

        A("clr %3")                        // idx = 0
        A("mov %14,%6")      
        A("mov %15,%7")      
        A("mov %16,%8")                    // nr = interval
        A("tst %16")                       // nr & 0xFF0000 == 0 ?
        A("brne 2f")                       // No, skip this
        A("mov %16,%15")      
        A("mov %15,%14")                   // nr <<= 8, %14 not needed
        A("subi %3,-8")                    // idx += 8
        A("tst %16")                       // nr & 0xFF0000 == 0 ?
        A("brne 2f")                       // No, skip this
        A("mov %16,%15")                   // nr <<= 8, %14 not needed
        A("clr %15")                       // We clear %14
        A("subi %3,-8")                    // idx += 8

        // here %16 != 0 and %16:%15 contains at least 9 MSBits, or both %16:%15 are 0
        L("2")
        A("cpi %16,0x10")                  // (nr & 0xF00000) == 0 ?
        A("brcc 3f")                       // No, skip this
        A("swap %15")                      // Swap nibbles
        A("swap %16")                      // Swap nibbles. Low nibble is 0
        A("mov %14, %15")      
        A("andi %14,0x0F")                 // Isolate low nibble
        A("andi %15,0xF0")                 // Keep proper nibble in %15
        A("or %16, %14")                   // %16:%15 <<= 4
        A("subi %3,-4")                    // idx += 4

        L("3")
        A("cpi %16,0x40")                  // (nr & 0xC00000) == 0 ?
        A("brcc 4f")                       // No, skip this
        A("add %15,%15")      
        A("adc %16,%16")      
        A("add %15,%15")      
        A("adc %16,%16")                   // %16:%15 <<= 2
        A("subi %3,-2")                    // idx += 2

        L("4")
        A("cpi %16,0x80")                  // (nr & 0x800000) == 0 ?
        A("brcc 5f")                       // No, skip this
        A("add %15,%15")      
        A("adc %16,%16")                   // %16:%15 <<= 1
        A("inc %3")                        // idx += 1

        // Now %16:%15 contains its MSBit set to 1, or %16:%15 is == 0. We are now absolutely sure
        // we have at least 9 MSBits available to enter the initial estimation table
        L("5")
        A("add %15,%15")      
        A("adc %16,%16")                   // %16:%15 = tidx = (nr <<= 1), we lose the top MSBit (always set to 1, %16 is the index into the inverse table)
        A("add r30,%16")                   // Only use top 8 bits
        A("adc r31,%13")                   // r31:r30 = inv_tab + (tidx)
        A("lpm %14, Z")                    // %14 = inv_tab[tidx]
        A("ldi %15, 1")                    // %15 = 1  %15:%14 = inv_tab[tidx] + 256

        // We must scale the approximation to the proper place
        A("clr %16")                       // %16 will always be 0 here
        A("subi %3,8")                     // idx == 8 ?
        A("breq 6f")                       // yes, no need to scale
        A("brcs 7f")                       // If C=1, means idx < 8, result was negative!

        // idx > 8, now %3 = idx - 8. We must perform a left shift. idx range:[1-8]
        A("sbrs %3,0")                     // shift by 1bit position?
        A("rjmp 8f")                       // No
        A("add %14,%14")      
        A("adc %15,%15")                   // %15:16 <<= 1
        L("8")
        A("sbrs %3,1")                     // shift by 2bit position?
        A("rjmp 9f")                       // No
        A("add %14,%14")      
        A("adc %15,%15")      
        A("add %14,%14")      
        A("adc %15,%15")                   // %15:16 <<= 1
        L("9")
        A("sbrs %3,2")                     // shift by 4bits position?
        A("rjmp 16f")                      // No
        A("swap %15")                      // Swap nibbles. lo nibble of %15 will always be 0
        A("swap %14")                      // Swap nibbles
        A("mov %12,%14")      
        A("andi %12,0x0F")                 // isolate low nibble
        A("andi %14,0xF0")                 // and clear it
        A("or %15,%12")                    // %15:%16 <<= 4
        L("16")
        A("sbrs %3,3")                     // shift by 8bits position?
        A("rjmp 6f")                       // No, we are done
        A("mov %16,%15")      
        A("mov %15,%14")      
        A("clr %14")      
        A("jmp 6f")      

        // idx < 8, now %3 = idx - 8. Get the count of bits
        L("7")
        A("neg %3")                        // %3 = -idx = count of bits to move right. idx range:[1...8]
        A("sbrs %3,0")                     // shift by 1 bit position ?
        A("rjmp 10f")                      // No, skip it
        A("asr %15")                       // (bit7 is always 0 here)
        A("ror %14")      
        L("10")
        A("sbrs %3,1")                     // shift by 2 bit position ?
        A("rjmp 11f")                      // No, skip it
        A("asr %15")                       // (bit7 is always 0 here)
        A("ror %14")      
        A("asr %15")                       // (bit7 is always 0 here)
        A("ror %14")      
        L("11")
        A("sbrs %3,2")                     // shift by 4 bit position ?
        A("rjmp 12f")                      // No, skip it
        A("swap %15")                      // Swap nibbles
        A("andi %14, 0xF0")                // Lose the lowest nibble
        A("swap %14")                      // Swap nibbles. Upper nibble is 0
        A("or %14,%15")                    // Pass nibble from upper byte
        A("andi %15, 0x0F")                // And get rid of that nibble
        L("12")
        A("sbrs %3,3")                     // shift by 8 bit position ?
        A("rjmp 6f")                       // No, skip it
        A("mov %14,%15")      
        A("clr %15")      
        L("6")                       // %16:%15:%14 = initial estimation of 0x1000000 / d

        // Now, we must refine the estimation present on %16:%15:%14 using 1 iteration
        // of Newton-Raphson. As it has a quadratic convergence, 1 iteration is enough
        // to get more than 18bits of precision (the initial table lookup gives 9 bits of
        // precision to start from). 18bits of precision is all what is needed here for result

        // %8:%7:%6 = d = interval
        // %16:%15:%14 = x = initial estimation of 0x1000000 / d
        // %13 = 0
        // %3:%2:%1:%0 = working accumulator

        // Compute 1<<25 - x*d. Result should never exceed 25 bits and should always be positive
        A("clr %0")      
        A("clr %1")      
        A("clr %2")      
        A("ldi %3,2")                      // %3:%2:%1:%0 = 0x2000000
        A("mul %6,%14")                    // r1:r0 = LO(d) * LO(x)
        A("sub %0,r0")      
        A("sbc %1,r1")      
        A("sbc %2,%13")      
        A("sbc %3,%13")                    // %3:%2:%1:%0 -= LO(d) * LO(x)
        A("mul %7,%14")                    // r1:r0 = MI(d) * LO(x)
        A("sub %1,r0")      
        A("sbc %2,r1" )      
        A("sbc %3,%13")                    // %3:%2:%1:%0 -= MI(d) * LO(x) << 8
        A("mul %8,%14")                    // r1:r0 = HI(d) * LO(x)
        A("sub %2,r0")      
        A("sbc %3,r1")                     // %3:%2:%1:%0 -= MIL(d) * LO(x) << 16
        A("mul %6,%15")                    // r1:r0 = LO(d) * MI(x)
        A("sub %1,r0")      
        A("sbc %2,r1")      
        A("sbc %3,%13")                    // %3:%2:%1:%0 -= LO(d) * MI(x) << 8
        A("mul %7,%15")                    // r1:r0 = MI(d) * MI(x)
        A("sub %2,r0")      
        A("sbc %3,r1")                     // %3:%2:%1:%0 -= MI(d) * MI(x) << 16
        A("mul %8,%15")                    // r1:r0 = HI(d) * MI(x)
        A("sub %3,r0")                     // %3:%2:%1:%0 -= MIL(d) * MI(x) << 24
        A("mul %6,%16")                    // r1:r0 = LO(d) * HI(x)
        A("sub %2,r0")      
        A("sbc %3,r1")                     // %3:%2:%1:%0 -= LO(d) * HI(x) << 16
        A("mul %7,%16")                    // r1:r0 = MI(d) * HI(x)
        A("sub %3,r0")                     // %3:%2:%1:%0 -= MI(d) * HI(x) << 24
        // %3:%2:%1:%0 = (1<<25) - x*d     [169]

        // We need to multiply that result by x, and we are only interested in the top 24bits of that multiply

        // %16:%15:%14 = x = initial estimation of 0x1000000 / d
        // %3:%2:%1:%0 = (1<<25) - x*d = acc
        // %13 = 0

        // result = %11:%10:%9:%5:%4
        A("mul %14,%0")                    // r1:r0 = LO(x) * LO(acc)
        A("mov %4,r1")      
        A("clr %5")      
        A("clr %9")      
        A("clr %10")      
        A("clr %11")                       // %11:%10:%9:%5:%4 = LO(x) * LO(acc) >> 8
        A("mul %15,%0")                    // r1:r0 = MI(x) * LO(acc)
        A("add %4,r0")      
        A("adc %5,r1")      
        A("adc %9,%13")      
        A("adc %10,%13")      
        A("adc %11,%13")                   // %11:%10:%9:%5:%4 += MI(x) * LO(acc)
        A("mul %16,%0")                    // r1:r0 = HI(x) * LO(acc)
        A("add %5,r0")      
        A("adc %9,r1")      
        A("adc %10,%13")      
        A("adc %11,%13")                   // %11:%10:%9:%5:%4 += MI(x) * LO(acc) << 8

        A("mul %14,%1")                    // r1:r0 = LO(x) * MIL(acc)
        A("add %4,r0")      
        A("adc %5,r1")      
        A("adc %9,%13")      
        A("adc %10,%13")      
        A("adc %11,%13")                   // %11:%10:%9:%5:%4 = LO(x) * MIL(acc)
        A("mul %15,%1")                    // r1:r0 = MI(x) * MIL(acc)
        A("add %5,r0")      
        A("adc %9,r1")      
        A("adc %10,%13")      
        A("adc %11,%13")                   // %11:%10:%9:%5:%4 += MI(x) * MIL(acc) << 8
        A("mul %16,%1")                    // r1:r0 = HI(x) * MIL(acc)
        A("add %9,r0")      
        A("adc %10,r1")      
        A("adc %11,%13")                   // %11:%10:%9:%5:%4 += MI(x) * MIL(acc) << 16

        A("mul %14,%2")                    // r1:r0 = LO(x) * MIH(acc)
        A("add %5,r0")      
        A("adc %9,r1")      
        A("adc %10,%13")      
        A("adc %11,%13")                   // %11:%10:%9:%5:%4 = LO(x) * MIH(acc) << 8
        A("mul %15,%2")                    // r1:r0 = MI(x) * MIH(acc)
        A("add %9,r0")      
        A("adc %10,r1")      
        A("adc %11,%13")                   // %11:%10:%9:%5:%4 += MI(x) * MIH(acc) << 16
        A("mul %16,%2")                    // r1:r0 = HI(x) * MIH(acc)
        A("add %10,r0")      
        A("adc %11,r1")                    // %11:%10:%9:%5:%4 += MI(x) * MIH(acc) << 24

        A("mul %14,%3")                    // r1:r0 = LO(x) * HI(acc)
        A("add %9,r0")      
        A("adc %10,r1")      
        A("adc %11,%13")                   // %11:%10:%9:%5:%4 = LO(x) * HI(acc) << 16
        A("mul %15,%3")                    // r1:r0 = MI(x) * HI(acc)
        A("add %10,r0")      
        A("adc %11,r1")                    // %11:%10:%9:%5:%4 += MI(x) * HI(acc) << 24
        A("mul %16,%3")                    // r1:r0 = HI(x) * HI(acc)
        A("add %11,r0")                    // %11:%10:%9:%5:%4 += MI(x) * HI(acc) << 32

        // At this point, %11:%10:%9 contains the new estimation of x.

        // Finally, we must correct the result. Estimate remainder as
        // (1<<24) - x*d
        // %11:%10:%9 = x
        // %8:%7:%6 = d = interval" "\n\t"
        A("ldi %3,1")      
        A("clr %2")      
        A("clr %1")      
        A("clr %0")                        // %3:%2:%1:%0 = 0x1000000
        A("mul %6,%9")                     // r1:r0 = LO(d) * LO(x)
        A("sub %0,r0")      
        A("sbc %1,r1")      
        A("sbc %2,%13")      
        A("sbc %3,%13")                    // %3:%2:%1:%0 -= LO(d) * LO(x)
        A("mul %7,%9")                     // r1:r0 = MI(d) * LO(x)
        A("sub %1,r0")      
        A("sbc %2,r1")      
        A("sbc %3,%13")                    // %3:%2:%1:%0 -= MI(d) * LO(x) << 8
        A("mul %8,%9")                     // r1:r0 = HI(d) * LO(x)
        A("sub %2,r0")      
        A("sbc %3,r1")                     // %3:%2:%1:%0 -= MIL(d) * LO(x) << 16
        A("mul %6,%10")                    // r1:r0 = LO(d) * MI(x)
        A("sub %1,r0")      
        A("sbc %2,r1")      
        A("sbc %3,%13")                    // %3:%2:%1:%0 -= LO(d) * MI(x) << 8
        A("mul %7,%10")                    // r1:r0 = MI(d) * MI(x)
        A("sub %2,r0")      
        A("sbc %3,r1")                     // %3:%2:%1:%0 -= MI(d) * MI(x) << 16
        A("mul %8,%10")                    // r1:r0 = HI(d) * MI(x)
        A("sub %3,r0")                     // %3:%2:%1:%0 -= MIL(d) * MI(x) << 24
        A("mul %6,%11")                    // r1:r0 = LO(d) * HI(x)
        A("sub %2,r0")      
        A("sbc %3,r1")                     // %3:%2:%1:%0 -= LO(d) * HI(x) << 16
        A("mul %7,%11")                    // r1:r0 = MI(d) * HI(x)
        A("sub %3,r0")                     // %3:%2:%1:%0 -= MI(d) * HI(x) << 24
        // %3:%2:%1:%0 = r = (1<<24) - x*d
        // %8:%7:%6 = d = interval

        // Perform the final correction
        A("sub %0,%6")      
        A("sbc %1,%7")      
        A("sbc %2,%8")                     // r -= d
        A("brcs 14f")                      // if ( r >= d)

        // %11:%10:%9 = x
        A("ldi %3,1")      
        A("add %9,%3")      
        A("adc %10,%13")      
        A("adc %11,%13")                   // x++
        L("14")

        // Estimation is done. %11:%10:%9 = x
        A("clr __zero_reg__")              // Make C runtime happy
        // [211 cycles total]
        : "=r" (r2),
          "=r" (r3),
          "=r" (r4),
          "=d" (r5),
          "=r" (r6),
          "=r" (r7),
          "+r" (r8),
          "+r" (r9),
          "+r" (r10),
          "=d" (r11),
          "=r" (r12),
          "=r" (r13),
          "=d" (r14),
          "=d" (r15),
          "=d" (r16),
          "=d" (r17),
          "=d" (r18),
          "+z" (ptab)
        :
        : "r0", "r1", "cc"
      );

      // Return the result
      return r11 | (uint16_t(r12) << 8) | (uint32_t(r13) << 16);
    }
  #else
    // All the other 32 CPUs can easily perform the inverse using hardware division,
    // so we don´t need to reduce precision or to use assembly language at all.

    // This routine, for all the other archs, returns 0x100000000 / d ~= 0xFFFFFFFF / d
    static FORCE_INLINE uint32_t get_period_inverse(uint32_t d) {
      return 0xFFFFFFFF / d;
    }
  #endif
#endif

#define MINIMAL_STEP_RATE 120

/**
 * Calculate trapezoid parameters, multiplying the entry- and exit-speeds
 * by the provided factors.
 */
void Planner::calculate_trapezoid_for_block(block_t* const block, const float &entry_factor, const float &exit_factor) {
  uint32_t initial_rate = CEIL(block->nominal_rate * entry_factor),
           final_rate = CEIL(block->nominal_rate * exit_factor); // (steps per second)

  // Limit minimal step rate (Otherwise the timer will overflow.)
  NOLESS(initial_rate, MINIMAL_STEP_RATE);
  NOLESS(final_rate, MINIMAL_STEP_RATE);

  #if ENABLED(BEZIER_JERK_CONTROL)
    uint32_t cruise_rate = initial_rate;
  #endif

  const int32_t accel = block->acceleration_steps_per_s2;

          // Steps required for acceleration, deceleration to/from nominal rate
  int32_t accelerate_steps = CEIL(estimate_acceleration_distance(initial_rate, block->nominal_rate, accel)),
          decelerate_steps = FLOOR(estimate_acceleration_distance(block->nominal_rate, final_rate, -accel)),
          // Steps between acceleration and deceleration, if any
          plateau_steps = block->step_event_count - accelerate_steps - decelerate_steps;

  // Does accelerate_steps + decelerate_steps exceed step_event_count?
  // Then we can't possibly reach the nominal rate, there will be no cruising.
  // Use intersection_distance() to calculate accel / braking time in order to
  // reach the final_rate exactly at the end of this block.
  if (plateau_steps < 0) {
    accelerate_steps = CEIL(intersection_distance(initial_rate, final_rate, accel, block->step_event_count));
    NOLESS(accelerate_steps, 0); // Check limits due to numerical round-off
    accelerate_steps = min((uint32_t)accelerate_steps, block->step_event_count);//(We can cast here to unsigned, because the above line ensures that we are above zero)
    plateau_steps = 0;

    #if ENABLED(BEZIER_JERK_CONTROL)
      // We won't reach the cruising rate. Let's calculate the speed we will reach
      cruise_rate = final_speed(initial_rate, accel, accelerate_steps);
    #endif
  }
  #if ENABLED(BEZIER_JERK_CONTROL)
    else // We have some plateau time, so the cruise rate will be the nominal rate
      cruise_rate = block->nominal_rate;
  #endif

  // block->accelerate_until = accelerate_steps;
  // block->decelerate_after = accelerate_steps+plateau_steps;

  #if ENABLED(BEZIER_JERK_CONTROL)
    // Jerk controlled speed requires to express speed versus time, NOT steps
    uint32_t acceleration_time = ((float)(cruise_rate - initial_rate) / accel) * (HAL_STEPPER_TIMER_RATE),
             deceleration_time = ((float)(cruise_rate - final_rate) / accel) * (HAL_STEPPER_TIMER_RATE);

    // And to offload calculations from the ISR, we also calculate the inverse of those times here
    uint32_t acceleration_time_inverse = get_period_inverse(acceleration_time);
    uint32_t deceleration_time_inverse = get_period_inverse(deceleration_time);

  #endif

  CRITICAL_SECTION_START;  // Fill variables used by the stepper in a critical section
  if (!TEST(block->flag, BLOCK_BIT_BUSY)) { // Don't update variables if block is busy.
    block->accelerate_until = accelerate_steps;
    block->decelerate_after = accelerate_steps + plateau_steps;
    block->initial_rate = initial_rate;
    #if ENABLED(BEZIER_JERK_CONTROL)
      block->acceleration_time = acceleration_time;
      block->deceleration_time = deceleration_time;
      block->acceleration_time_inverse = acceleration_time_inverse;
      block->deceleration_time_inverse = deceleration_time_inverse;
      block->cruise_rate = cruise_rate;
    #endif
    block->final_rate = final_rate;
  }
  CRITICAL_SECTION_END;
}

// "Junction jerk" in this context is the immediate change in speed at the junction of two blocks.
// This method will calculate the junction jerk as the euclidean distance between the nominal
// velocities of the respective blocks.
//inline float junction_jerk(block_t *before, block_t *after) {
//  return SQRT(
//    POW((before->speed_x-after->speed_x), 2)+POW((before->speed_y-after->speed_y), 2));
//}


// The kernel called by recalculate() when scanning the plan from last to first entry.
void Planner::reverse_pass_kernel(block_t* const current, const block_t * const next) {
  if (!current || !next) return;
  // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
  // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
  // check for maximum allowable speed reductions to ensure maximum possible planned speed.
  float max_entry_speed = current->max_entry_speed;
  if (current->entry_speed != max_entry_speed) {
    // If nominal length true, max junction speed is guaranteed to be reached. Only compute
    // for max allowable speed if block is decelerating and nominal length is false.
    current->entry_speed = (TEST(current->flag, BLOCK_BIT_NOMINAL_LENGTH) || max_entry_speed <= next->entry_speed)
      ? max_entry_speed
      : min(max_entry_speed, max_allowable_speed(-current->acceleration, next->entry_speed, current->millimeters));
    SBI(current->flag, BLOCK_BIT_RECALCULATE);
  }
}

/**
 * recalculate() needs to go over the current plan twice.
 * Once in reverse and once forward. This implements the reverse pass.
 */
void Planner::reverse_pass() {
  if (movesplanned() > 2) {
    const uint8_t endnr = BLOCK_MOD(block_buffer_tail + 1); // tail is running. tail+1 shouldn't be altered because it's connected to the running block.
    uint8_t blocknr = prev_block_index(block_buffer_head);
    block_t* current = &block_buffer[blocknr];

    // Last/newest block in buffer:
    const float max_entry_speed = current->max_entry_speed;
    if (current->entry_speed != max_entry_speed) {
      // If nominal length true, max junction speed is guaranteed to be reached. Only compute
      // for max allowable speed if block is decelerating and nominal length is false.
      current->entry_speed = TEST(current->flag, BLOCK_BIT_NOMINAL_LENGTH)
        ? max_entry_speed
        : min(max_entry_speed, max_allowable_speed(-current->acceleration, MINIMUM_PLANNER_SPEED, current->millimeters));
      SBI(current->flag, BLOCK_BIT_RECALCULATE);
    }

    do {
      const block_t * const next = current;
      blocknr = prev_block_index(blocknr);
      current = &block_buffer[blocknr];
      reverse_pass_kernel(current, next);
    } while (blocknr != endnr);
  }
}

// The kernel called by recalculate() when scanning the plan from first to last entry.
void Planner::forward_pass_kernel(const block_t * const previous, block_t* const current) {
  if (!previous) return;

  // If the previous block is an acceleration block, but it is not long enough to complete the
  // full speed change within the block, we need to adjust the entry speed accordingly. Entry
  // speeds have already been reset, maximized, and reverse planned by reverse planner.
  // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
  if (!TEST(previous->flag, BLOCK_BIT_NOMINAL_LENGTH)) {
    if (previous->entry_speed < current->entry_speed) {
      float entry_speed = min(current->entry_speed,
                               max_allowable_speed(-previous->acceleration, previous->entry_speed, previous->millimeters));
      // Check for junction speed change
      if (current->entry_speed != entry_speed) {
        current->entry_speed = entry_speed;
        SBI(current->flag, BLOCK_BIT_RECALCULATE);
      }
    }
  }
}

/**
 * recalculate() needs to go over the current plan twice.
 * Once in reverse and once forward. This implements the forward pass.
 */
void Planner::forward_pass() {
  block_t* block[3] = { NULL, NULL, NULL };

  for (uint8_t b = block_buffer_tail; b != block_buffer_head; b = next_block_index(b)) {
    block[0] = block[1];
    block[1] = block[2];
    block[2] = &block_buffer[b];
    forward_pass_kernel(block[0], block[1]);
  }
  forward_pass_kernel(block[1], block[2]);
}

/**
 * Recalculate the trapezoid speed profiles for all blocks in the plan
 * according to the entry_factor for each junction. Must be called by
 * recalculate() after updating the blocks.
 */
void Planner::recalculate_trapezoids() {
  int8_t block_index = block_buffer_tail;
  block_t *current, *next = NULL;

  while (block_index != block_buffer_head) {
    current = next;
    next = &block_buffer[block_index];
    if (current) {
      // Recalculate if current block entry or exit junction speed has changed.
      if (TEST(current->flag, BLOCK_BIT_RECALCULATE) || TEST(next->flag, BLOCK_BIT_RECALCULATE)) {
        // NOTE: Entry and exit factors always > 0 by all previous logic operations.
        const float nomr = 1.0 / current->nominal_speed;
        calculate_trapezoid_for_block(current, current->entry_speed * nomr, next->entry_speed * nomr);
        #if ENABLED(LIN_ADVANCE)
          if (current->use_advance_lead) {
            const float comp = current->e_D_ratio * extruder_advance_K * axis_steps_per_mm[E_AXIS];
            current->max_adv_steps = current->nominal_speed * comp;
            current->final_adv_steps = next->entry_speed * comp;
          }
        #endif
        CBI(current->flag, BLOCK_BIT_RECALCULATE); // Reset current only to ensure next trapezoid is computed
      }
    }
    block_index = next_block_index(block_index);
  }
  // Last/newest block in buffer. Exit speed is set with MINIMUM_PLANNER_SPEED. Always recalculated.
  if (next) {
    const float nomr = 1.0 / next->nominal_speed;
    calculate_trapezoid_for_block(next, next->entry_speed * nomr, (MINIMUM_PLANNER_SPEED) * nomr);
    #if ENABLED(LIN_ADVANCE)
      if (next->use_advance_lead) {
        const float comp = next->e_D_ratio * extruder_advance_K * axis_steps_per_mm[E_AXIS];
        next->max_adv_steps = next->nominal_speed * comp;
        next->final_adv_steps = (MINIMUM_PLANNER_SPEED) * comp;
      }
    #endif
    CBI(next->flag, BLOCK_BIT_RECALCULATE);
  }
}

/**
 * Recalculate the motion plan according to the following algorithm:
 *
 *   1. Go over every block in reverse order...
 *
 *      Calculate a junction speed reduction (block_t.entry_factor) so:
 *
 *      a. The junction jerk is within the set limit, and
 *
 *      b. No speed reduction within one block requires faster
 *         deceleration than the one, true constant acceleration.
 *
 *   2. Go over every block in chronological order...
 *
 *      Dial down junction speed reduction values if:
 *      a. The speed increase within one block would require faster
 *         acceleration than the one, true constant acceleration.
 *
 * After that, all blocks will have an entry_factor allowing all speed changes to
 * be performed using only the one, true constant acceleration, and where no junction
 * jerk is jerkier than the set limit, Jerky. Finally it will:
 *
 *   3. Recalculate "trapezoids" for all blocks.
 */
void Planner::recalculate() {
  reverse_pass();
  forward_pass();
  recalculate_trapezoids();
}

#if ENABLED(AUTOTEMP)

  void Planner::getHighESpeed() {
    static float oldt = 0;

    if (!autotemp_enabled) return;
    if (thermalManager.degTargetHotend(0) + 2 < autotemp_min) return; // probably temperature set to zero.

    float high = 0.0;
    for (uint8_t b = block_buffer_tail; b != block_buffer_head; b = next_block_index(b)) {
      block_t* block = &block_buffer[b];
      if (block->steps[X_AXIS] || block->steps[Y_AXIS] || block->steps[Z_AXIS]) {
        float se = (float)block->steps[E_AXIS] / block->step_event_count * block->nominal_speed; // mm/sec;
        NOLESS(high, se);
      }
    }

    float t = autotemp_min + high * autotemp_factor;
    t = constrain(t, autotemp_min, autotemp_max);
    if (t < oldt) t = t * (1 - (AUTOTEMP_OLDWEIGHT)) + oldt * (AUTOTEMP_OLDWEIGHT);
    oldt = t;
    thermalManager.setTargetHotend(t, 0);
  }

#endif // AUTOTEMP

/**
 * Maintain fans, paste extruder pressure,
 */
void Planner::check_axes_activity() {
  unsigned char axis_active[NUM_AXIS] = { 0 },
                tail_fan_speed[FAN_COUNT];

  #if ENABLED(BARICUDA)
    #if HAS_HEATER_1
      uint8_t tail_valve_pressure;
    #endif
    #if HAS_HEATER_2
      uint8_t tail_e_to_p_pressure;
    #endif
  #endif

  if (has_blocks_queued()) {

    #if FAN_COUNT > 0
      for (uint8_t i = 0; i < FAN_COUNT; i++)
        tail_fan_speed[i] = block_buffer[block_buffer_tail].fan_speed[i];
    #endif

    block_t* block;

    #if ENABLED(BARICUDA)
      block = &block_buffer[block_buffer_tail];
      #if HAS_HEATER_1
        tail_valve_pressure = block->valve_pressure;
      #endif
      #if HAS_HEATER_2
        tail_e_to_p_pressure = block->e_to_p_pressure;
      #endif
    #endif

    for (uint8_t b = block_buffer_tail; b != block_buffer_head; b = next_block_index(b)) {
      block = &block_buffer[b];
      LOOP_XYZE(i) if (block->steps[i]) axis_active[i]++;
    }
  }
  else {
    #if FAN_COUNT > 0
      for (uint8_t i = 0; i < FAN_COUNT; i++) tail_fan_speed[i] = fanSpeeds[i];
    #endif

    #if ENABLED(BARICUDA)
      #if HAS_HEATER_1
        tail_valve_pressure = baricuda_valve_pressure;
      #endif
      #if HAS_HEATER_2
        tail_e_to_p_pressure = baricuda_e_to_p_pressure;
      #endif
    #endif
  }

  #if ENABLED(DISABLE_X)
    if (!axis_active[X_AXIS]) disable_X();
  #endif
  #if ENABLED(DISABLE_Y)
    if (!axis_active[Y_AXIS]) disable_Y();
  #endif
  #if ENABLED(DISABLE_Z)
    if (!axis_active[Z_AXIS]) disable_Z();
  #endif
  #if ENABLED(DISABLE_E)
    if (!axis_active[E_AXIS]) disable_e_steppers();
  #endif

  #if FAN_COUNT > 0

    #if FAN_KICKSTART_TIME > 0

      static millis_t fan_kick_end[FAN_COUNT] = { 0 };

      #define KICKSTART_FAN(f) \
        if (tail_fan_speed[f]) { \
          millis_t ms = millis(); \
          if (fan_kick_end[f] == 0) { \
            fan_kick_end[f] = ms + FAN_KICKSTART_TIME; \
            tail_fan_speed[f] = 255; \
          } else if (PENDING(ms, fan_kick_end[f])) \
            tail_fan_speed[f] = 255; \
        } else fan_kick_end[f] = 0

      #if HAS_FAN0
        KICKSTART_FAN(0);
      #endif
      #if HAS_FAN1
        KICKSTART_FAN(1);
      #endif
      #if HAS_FAN2
        KICKSTART_FAN(2);
      #endif

    #endif // FAN_KICKSTART_TIME > 0

    #ifdef FAN_MIN_PWM
      #define CALC_FAN_SPEED(f) (tail_fan_speed[f] ? ( FAN_MIN_PWM + (tail_fan_speed[f] * (255 - FAN_MIN_PWM)) / 255 ) : 0)
    #else
      #define CALC_FAN_SPEED(f) tail_fan_speed[f]
    #endif

    #if ENABLED(FAN_SOFT_PWM)
      #if HAS_FAN0
        thermalManager.soft_pwm_amount_fan[0] = CALC_FAN_SPEED(0);
      #endif
      #if HAS_FAN1
        thermalManager.soft_pwm_amount_fan[1] = CALC_FAN_SPEED(1);
      #endif
      #if HAS_FAN2
        thermalManager.soft_pwm_amount_fan[2] = CALC_FAN_SPEED(2);
      #endif
    #else
      #if HAS_FAN0
        analogWrite(FAN_PIN, CALC_FAN_SPEED(0));
      #endif
      #if HAS_FAN1
        analogWrite(FAN1_PIN, CALC_FAN_SPEED(1));
      #endif
      #if HAS_FAN2
        analogWrite(FAN2_PIN, CALC_FAN_SPEED(2));
      #endif
    #endif

  #endif // FAN_COUNT > 0

  #if ENABLED(AUTOTEMP)
    getHighESpeed();
  #endif

  #if ENABLED(BARICUDA)
    #if HAS_HEATER_1
      analogWrite(HEATER_1_PIN, tail_valve_pressure);
    #endif
    #if HAS_HEATER_2
      analogWrite(HEATER_2_PIN, tail_e_to_p_pressure);
    #endif
  #endif
}

#if DISABLED(NO_VOLUMETRICS)

  /**
   * Get a volumetric multiplier from a filament diameter.
   * This is the reciprocal of the circular cross-section area.
   * Return 1.0 with volumetric off or a diameter of 0.0.
   */
  inline float calculate_volumetric_multiplier(const float &diameter) {
    return (parser.volumetric_enabled && diameter) ? 1.0 / CIRCLE_AREA(diameter * 0.5) : 1.0;
  }

  /**
   * Convert the filament sizes into volumetric multipliers.
   * The multiplier converts a given E value into a length.
   */
  void Planner::calculate_volumetric_multipliers() {
    for (uint8_t i = 0; i < COUNT(filament_size); i++) {
      volumetric_multiplier[i] = calculate_volumetric_multiplier(filament_size[i]);
      refresh_e_factor(i);
    }
  }

#endif // !NO_VOLUMETRICS

#if ENABLED(FILAMENT_WIDTH_SENSOR)
  /**
   * Convert the ratio value given by the filament width sensor
   * into a volumetric multiplier. Conversion differs when using
   * linear extrusion vs volumetric extrusion.
   */
  void Planner::calculate_volumetric_for_width_sensor(const int8_t encoded_ratio) {
    // Reconstitute the nominal/measured ratio
    const float nom_meas_ratio = 1.0 + 0.01 * encoded_ratio,
                ratio_2 = sq(nom_meas_ratio);

    volumetric_multiplier[FILAMENT_SENSOR_EXTRUDER_NUM] = parser.volumetric_enabled
      ? ratio_2 / CIRCLE_AREA(filament_width_nominal * 0.5) // Volumetric uses a true volumetric multiplier
      : ratio_2;                                            // Linear squares the ratio, which scales the volume

    refresh_e_factor(FILAMENT_SENSOR_EXTRUDER_NUM);
  }
#endif

#if PLANNER_LEVELING
  /**
   * rx, ry, rz - Cartesian positions in mm
   *              Leveled XYZ on completion
   */
  void Planner::apply_leveling(float &rx, float &ry, float &rz) {

    #if ENABLED(SKEW_CORRECTION)
      skew(rx, ry, rz);
    #endif

    if (!leveling_active) return;

    #if ABL_PLANAR

      float dx = rx - (X_TILT_FULCRUM),
            dy = ry - (Y_TILT_FULCRUM);

      apply_rotation_xyz(bed_level_matrix, dx, dy, rz);

      rx = dx + X_TILT_FULCRUM;
      ry = dy + Y_TILT_FULCRUM;

    #elif HAS_MESH

      #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
        const float fade_scaling_factor = fade_scaling_factor_for_z(rz);
      #else
        constexpr float fade_scaling_factor = 1.0;
      #endif

      #if ENABLED(AUTO_BED_LEVELING_BILINEAR)
        const float raw[XYZ] = { rx, ry, 0 };
      #endif

      rz += (
        #if ENABLED(MESH_BED_LEVELING)
          mbl.get_z(rx, ry
            #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
              , fade_scaling_factor
            #endif
          )
        #elif ENABLED(AUTO_BED_LEVELING_UBL)
          fade_scaling_factor ? fade_scaling_factor * ubl.get_z_correction(rx, ry) : 0.0
        #elif ENABLED(AUTO_BED_LEVELING_BILINEAR)
          fade_scaling_factor ? fade_scaling_factor * bilinear_z_offset(raw) : 0.0
        #endif
      );

    #endif
  }

  void Planner::unapply_leveling(float raw[XYZ]) {

    if (leveling_active) {

      #if ABL_PLANAR

        matrix_3x3 inverse = matrix_3x3::transpose(bed_level_matrix);

        float dx = raw[X_AXIS] - (X_TILT_FULCRUM),
              dy = raw[Y_AXIS] - (Y_TILT_FULCRUM);

        apply_rotation_xyz(inverse, dx, dy, raw[Z_AXIS]);

        raw[X_AXIS] = dx + X_TILT_FULCRUM;
        raw[Y_AXIS] = dy + Y_TILT_FULCRUM;

      #elif HAS_MESH

        #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
          const float fade_scaling_factor = fade_scaling_factor_for_z(raw[Z_AXIS]);
        #else
          constexpr float fade_scaling_factor = 1.0;
        #endif

        raw[Z_AXIS] -= (
          #if ENABLED(MESH_BED_LEVELING)
            mbl.get_z(raw[X_AXIS], raw[Y_AXIS]
              #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
                , fade_scaling_factor
              #endif
            )
          #elif ENABLED(AUTO_BED_LEVELING_UBL)
            fade_scaling_factor ? fade_scaling_factor * ubl.get_z_correction(raw[X_AXIS], raw[Y_AXIS]) : 0.0
          #elif ENABLED(AUTO_BED_LEVELING_BILINEAR)
            fade_scaling_factor ? fade_scaling_factor * bilinear_z_offset(raw) : 0.0
          #endif
        );

      #endif
    }

    #if ENABLED(SKEW_CORRECTION)
      unskew(raw[X_AXIS], raw[Y_AXIS], raw[Z_AXIS]);
    #endif
  }

#endif // PLANNER_LEVELING

/**
 * Planner::_buffer_steps
 *
 * Add a new linear movement to the buffer (in terms of steps).
 *
 *  target      - target position in steps units
 *  fr_mm_s     - (target) speed of the move
 *  extruder    - target extruder
 */
void Planner::_buffer_steps(const int32_t (&target)[XYZE]
  #if HAS_POSITION_FLOAT
    , const float (&target_float)[XYZE]
  #endif
  , float fr_mm_s, const uint8_t extruder, const float &millimeters/*=0.0*/
) {

  const int32_t da = target[A_AXIS] - position[A_AXIS],
                db = target[B_AXIS] - position[B_AXIS],
                dc = target[C_AXIS] - position[C_AXIS];

  int32_t de = target[E_AXIS] - position[E_AXIS];

  /* <-- add a slash to enable
    SERIAL_ECHOPAIR("  _buffer_steps FR:", fr_mm_s);
    SERIAL_ECHOPAIR(" A:", target[A_AXIS]);
    SERIAL_ECHOPAIR(" (", da);
    SERIAL_ECHOPAIR(" steps) B:", target[B_AXIS]);
    SERIAL_ECHOPAIR(" (", db);
    SERIAL_ECHOPAIR(" steps) C:", target[C_AXIS]);
    SERIAL_ECHOPAIR(" (", dc);
    SERIAL_ECHOPAIR(" steps) E:", target[E_AXIS]);
    SERIAL_ECHOPAIR(" (", de);
    SERIAL_ECHOLNPGM(" steps)");
  //*/

  #if ENABLED(PREVENT_COLD_EXTRUSION) || ENABLED(PREVENT_LENGTHY_EXTRUDE)
    if (de) {
      #if ENABLED(PREVENT_COLD_EXTRUSION)
        if (thermalManager.tooColdToExtrude(extruder)) {
          position[E_AXIS] = target[E_AXIS]; // Behave as if the move really took place, but ignore E part
          #if HAS_POSITION_FLOAT
            position_float[E_AXIS] = target_float[E_AXIS];
          #endif
          de = 0; // no difference
          SERIAL_ECHO_START();
          SERIAL_ECHOLNPGM(MSG_ERR_COLD_EXTRUDE_STOP);
        }
      #endif // PREVENT_COLD_EXTRUSION
      #if ENABLED(PREVENT_LENGTHY_EXTRUDE)
        if (labs(de * e_factor[extruder]) > (int32_t)axis_steps_per_mm[E_AXIS_N] * (EXTRUDE_MAXLENGTH)) { // It's not important to get max. extrusion length in a precision < 1mm, so save some cycles and cast to int
          position[E_AXIS] = target[E_AXIS]; // Behave as if the move really took place, but ignore E part
          #if HAS_POSITION_FLOAT
            position_float[E_AXIS] = target_float[E_AXIS];
          #endif
          de = 0; // no difference
          SERIAL_ECHO_START();
          SERIAL_ECHOLNPGM(MSG_ERR_LONG_EXTRUDE_STOP);
        }
      #endif // PREVENT_LENGTHY_EXTRUDE
    }
  #endif // PREVENT_COLD_EXTRUSION || PREVENT_LENGTHY_EXTRUDE

  // Compute direction bit-mask for this block
  uint8_t dm = 0;
  #if CORE_IS_XY
    if (da < 0) SBI(dm, X_HEAD);                // Save the real Extruder (head) direction in X Axis
    if (db < 0) SBI(dm, Y_HEAD);                // ...and Y
    if (dc < 0) SBI(dm, Z_AXIS);
    if (da + db < 0) SBI(dm, A_AXIS);           // Motor A direction
    if (CORESIGN(da - db) < 0) SBI(dm, B_AXIS); // Motor B direction
  #elif CORE_IS_XZ
    if (da < 0) SBI(dm, X_HEAD);                // Save the real Extruder (head) direction in X Axis
    if (db < 0) SBI(dm, Y_AXIS);
    if (dc < 0) SBI(dm, Z_HEAD);                // ...and Z
    if (da + dc < 0) SBI(dm, A_AXIS);           // Motor A direction
    if (CORESIGN(da - dc) < 0) SBI(dm, C_AXIS); // Motor C direction
  #elif CORE_IS_YZ
    if (da < 0) SBI(dm, X_AXIS);
    if (db < 0) SBI(dm, Y_HEAD);                // Save the real Extruder (head) direction in Y Axis
    if (dc < 0) SBI(dm, Z_HEAD);                // ...and Z
    if (db + dc < 0) SBI(dm, B_AXIS);           // Motor B direction
    if (CORESIGN(db - dc) < 0) SBI(dm, C_AXIS); // Motor C direction
  #else
    if (da < 0) SBI(dm, X_AXIS);
    if (db < 0) SBI(dm, Y_AXIS);
    if (dc < 0) SBI(dm, Z_AXIS);
  #endif
  if (de < 0) SBI(dm, E_AXIS);

  const float esteps_float = de * e_factor[extruder];
  const int32_t esteps = abs(esteps_float) + 0.5;

  // Wait for the next available block
  uint8_t next_buffer_head;
  block_t * const block = get_next_free_block(next_buffer_head);

  // Clear all flags, including the "busy" bit
  block->flag = 0x00;

  // Set direction bits
  block->direction_bits = dm;

  // Number of steps for each axis
  // See http://www.corexy.com/theory.html
  #if CORE_IS_XY
    block->steps[A_AXIS] = labs(da + db);
    block->steps[B_AXIS] = labs(da - db);
    block->steps[Z_AXIS] = labs(dc);
  #elif CORE_IS_XZ
    block->steps[A_AXIS] = labs(da + dc);
    block->steps[Y_AXIS] = labs(db);
    block->steps[C_AXIS] = labs(da - dc);
  #elif CORE_IS_YZ
    block->steps[X_AXIS] = labs(da);
    block->steps[B_AXIS] = labs(db + dc);
    block->steps[C_AXIS] = labs(db - dc);
  #elif IS_SCARA
    block->steps[A_AXIS] = labs(da);
    block->steps[B_AXIS] = labs(db);
    block->steps[Z_AXIS] = labs(dc);
  #else
    // default non-h-bot planning
    block->steps[A_AXIS] = labs(da);
    block->steps[B_AXIS] = labs(db);
    block->steps[C_AXIS] = labs(dc);
  #endif

  block->steps[E_AXIS] = esteps;
  block->step_event_count = MAX4(block->steps[A_AXIS], block->steps[B_AXIS], block->steps[C_AXIS], esteps);

  // Bail if this is a zero-length block
  if (block->step_event_count < MIN_STEPS_PER_SEGMENT) return;

  // For a mixing extruder, get a magnified step_event_count for each
  #if ENABLED(MIXING_EXTRUDER)
    for (uint8_t i = 0; i < MIXING_STEPPERS; i++)
      block->mix_event_count[i] = mixing_factor[i] * block->step_event_count;
  #endif

  #if FAN_COUNT > 0
    for (uint8_t i = 0; i < FAN_COUNT; i++) block->fan_speed[i] = fanSpeeds[i];
  #endif

  #if ENABLED(BARICUDA)
    block->valve_pressure = baricuda_valve_pressure;
    block->e_to_p_pressure = baricuda_e_to_p_pressure;
  #endif

  block->active_extruder = extruder;

  #if ENABLED(AUTO_POWER_CONTROL)
    if (block->steps[X_AXIS] || block->steps[Y_AXIS] || block->steps[Z_AXIS])
      powerManager.power_on();
  #endif

  // Enable active axes
  #if CORE_IS_XY
    if (block->steps[A_AXIS] || block->steps[B_AXIS]) {
      enable_X();
      enable_Y();
    }
    #if DISABLED(Z_LATE_ENABLE)
      if (block->steps[Z_AXIS]) enable_Z();
    #endif
  #elif CORE_IS_XZ
    if (block->steps[A_AXIS] || block->steps[C_AXIS]) {
      enable_X();
      enable_Z();
    }
    if (block->steps[Y_AXIS]) enable_Y();
  #elif CORE_IS_YZ
    if (block->steps[B_AXIS] || block->steps[C_AXIS]) {
      enable_Y();
      enable_Z();
    }
    if (block->steps[X_AXIS]) enable_X();
  #else
    if (block->steps[X_AXIS]) enable_X();
    if (block->steps[Y_AXIS]) enable_Y();
    #if DISABLED(Z_LATE_ENABLE)
      if (block->steps[Z_AXIS]) enable_Z();
    #endif
  #endif

  // Enable extruder(s)
  if (esteps) {
    #if ENABLED(AUTO_POWER_CONTROL)
      powerManager.power_on();
    #endif

    #if ENABLED(DISABLE_INACTIVE_EXTRUDER) // Enable only the selected extruder

      #define DISABLE_IDLE_E(N) if (!g_uc_extruder_last_move[N]) disable_E##N();

      for (uint8_t i = 0; i < EXTRUDERS; i++)
        if (g_uc_extruder_last_move[i] > 0) g_uc_extruder_last_move[i]--;

      switch (extruder) {
        case 0:
          #if EXTRUDERS > 1
            DISABLE_IDLE_E(1);
            #if EXTRUDERS > 2
              DISABLE_IDLE_E(2);
              #if EXTRUDERS > 3
                DISABLE_IDLE_E(3);
                #if EXTRUDERS > 4
                  DISABLE_IDLE_E(4);
                #endif // EXTRUDERS > 4
              #endif // EXTRUDERS > 3
            #endif // EXTRUDERS > 2
          #endif // EXTRUDERS > 1
          enable_E0();
          g_uc_extruder_last_move[0] = (BLOCK_BUFFER_SIZE) * 2;
          #if ENABLED(DUAL_X_CARRIAGE) || ENABLED(DUAL_NOZZLE_DUPLICATION_MODE)
            if (extruder_duplication_enabled) {
              enable_E1();
              g_uc_extruder_last_move[1] = (BLOCK_BUFFER_SIZE) * 2;
            }
          #endif
        break;
        #if EXTRUDERS > 1
          case 1:
            DISABLE_IDLE_E(0);
            #if EXTRUDERS > 2
              DISABLE_IDLE_E(2);
              #if EXTRUDERS > 3
                DISABLE_IDLE_E(3);
                #if EXTRUDERS > 4
                  DISABLE_IDLE_E(4);
                #endif // EXTRUDERS > 4
              #endif // EXTRUDERS > 3
            #endif // EXTRUDERS > 2
            enable_E1();
            g_uc_extruder_last_move[1] = (BLOCK_BUFFER_SIZE) * 2;
          break;
          #if EXTRUDERS > 2
            case 2:
              DISABLE_IDLE_E(0);
              DISABLE_IDLE_E(1);
              #if EXTRUDERS > 3
                DISABLE_IDLE_E(3);
                #if EXTRUDERS > 4
                  DISABLE_IDLE_E(4);
                #endif
              #endif
              enable_E2();
              g_uc_extruder_last_move[2] = (BLOCK_BUFFER_SIZE) * 2;
            break;
            #if EXTRUDERS > 3
              case 3:
                DISABLE_IDLE_E(0);
                DISABLE_IDLE_E(1);
                DISABLE_IDLE_E(2);
                #if EXTRUDERS > 4
                  DISABLE_IDLE_E(4);
                #endif
                enable_E3();
                g_uc_extruder_last_move[3] = (BLOCK_BUFFER_SIZE) * 2;
              break;
              #if EXTRUDERS > 4
                case 4:
                  DISABLE_IDLE_E(0);
                  DISABLE_IDLE_E(1);
                  DISABLE_IDLE_E(2);
                  DISABLE_IDLE_E(3);
                  enable_E4();
                  g_uc_extruder_last_move[4] = (BLOCK_BUFFER_SIZE) * 2;
                break;
              #endif // EXTRUDERS > 4
            #endif // EXTRUDERS > 3
          #endif // EXTRUDERS > 2
        #endif // EXTRUDERS > 1
      }
    #else
      enable_E0();
      enable_E1();
      enable_E2();
      enable_E3();
      enable_E4();
    #endif
  }

  if (esteps)
    NOLESS(fr_mm_s, min_feedrate_mm_s);
  else
    NOLESS(fr_mm_s, min_travel_feedrate_mm_s);

  /**
   * This part of the code calculates the total length of the movement.
   * For cartesian bots, the X_AXIS is the real X movement and same for Y_AXIS.
   * But for corexy bots, that is not true. The "X_AXIS" and "Y_AXIS" motors (that should be named to A_AXIS
   * and B_AXIS) cannot be used for X and Y length, because A=X+Y and B=X-Y.
   * So we need to create other 2 "AXIS", named X_HEAD and Y_HEAD, meaning the real displacement of the Head.
   * Having the real displacement of the head, we can calculate the total movement length and apply the desired speed.
   */
  #if IS_CORE
    float delta_mm[Z_HEAD + 1];
    #if CORE_IS_XY
      delta_mm[X_HEAD] = da * steps_to_mm[A_AXIS];
      delta_mm[Y_HEAD] = db * steps_to_mm[B_AXIS];
      delta_mm[Z_AXIS] = dc * steps_to_mm[Z_AXIS];
      delta_mm[A_AXIS] = (da + db) * steps_to_mm[A_AXIS];
      delta_mm[B_AXIS] = CORESIGN(da - db) * steps_to_mm[B_AXIS];
    #elif CORE_IS_XZ
      delta_mm[X_HEAD] = da * steps_to_mm[A_AXIS];
      delta_mm[Y_AXIS] = db * steps_to_mm[Y_AXIS];
      delta_mm[Z_HEAD] = dc * steps_to_mm[C_AXIS];
      delta_mm[A_AXIS] = (da + dc) * steps_to_mm[A_AXIS];
      delta_mm[C_AXIS] = CORESIGN(da - dc) * steps_to_mm[C_AXIS];
    #elif CORE_IS_YZ
      delta_mm[X_AXIS] = da * steps_to_mm[X_AXIS];
      delta_mm[Y_HEAD] = db * steps_to_mm[B_AXIS];
      delta_mm[Z_HEAD] = dc * steps_to_mm[C_AXIS];
      delta_mm[B_AXIS] = (db + dc) * steps_to_mm[B_AXIS];
      delta_mm[C_AXIS] = CORESIGN(db - dc) * steps_to_mm[C_AXIS];
    #endif
  #else
    float delta_mm[ABCE];
    delta_mm[A_AXIS] = da * steps_to_mm[A_AXIS];
    delta_mm[B_AXIS] = db * steps_to_mm[B_AXIS];
    delta_mm[C_AXIS] = dc * steps_to_mm[C_AXIS];
  #endif
  delta_mm[E_AXIS] = esteps_float * steps_to_mm[E_AXIS_N];

  if (block->steps[A_AXIS] < MIN_STEPS_PER_SEGMENT && block->steps[B_AXIS] < MIN_STEPS_PER_SEGMENT && block->steps[C_AXIS] < MIN_STEPS_PER_SEGMENT) {
    block->millimeters = FABS(delta_mm[E_AXIS]);
  }
  else if (!millimeters) {
    block->millimeters = SQRT(
      #if CORE_IS_XY
        sq(delta_mm[X_HEAD]) + sq(delta_mm[Y_HEAD]) + sq(delta_mm[Z_AXIS])
      #elif CORE_IS_XZ
        sq(delta_mm[X_HEAD]) + sq(delta_mm[Y_AXIS]) + sq(delta_mm[Z_HEAD])
      #elif CORE_IS_YZ
        sq(delta_mm[X_AXIS]) + sq(delta_mm[Y_HEAD]) + sq(delta_mm[Z_HEAD])
      #else
        sq(delta_mm[X_AXIS]) + sq(delta_mm[Y_AXIS]) + sq(delta_mm[Z_AXIS])
      #endif
    );
  }
  else
    block->millimeters = millimeters;

  const float inverse_millimeters = 1.0 / block->millimeters;  // Inverse millimeters to remove multiple divides

  // Calculate inverse time for this move. No divide by zero due to previous checks.
  // Example: At 120mm/s a 60mm move takes 0.5s. So this will give 2.0.
  float inverse_secs = fr_mm_s * inverse_millimeters;

  const uint8_t moves_queued = movesplanned();

  // Slow down when the buffer starts to empty, rather than wait at the corner for a buffer refill
  #if ENABLED(SLOWDOWN) || ENABLED(ULTRA_LCD) || defined(XY_FREQUENCY_LIMIT)
    // Segment time im micro seconds
    uint32_t segment_time_us = LROUND(1000000.0 / inverse_secs);
  #endif

  #if ENABLED(SLOWDOWN)
    if (WITHIN(moves_queued, 2, (BLOCK_BUFFER_SIZE) / 2 - 1)) {
      if (segment_time_us < min_segment_time_us) {
        // buffer is draining, add extra time.  The amount of time added increases if the buffer is still emptied more.
        const uint32_t nst = segment_time_us + LROUND(2 * (min_segment_time_us - segment_time_us) / moves_queued);
        inverse_secs = 1000000.0 / nst;
        #if defined(XY_FREQUENCY_LIMIT) || ENABLED(ULTRA_LCD)
          segment_time_us = nst;
        #endif
      }
    }
  #endif

  #if ENABLED(ULTRA_LCD)
    CRITICAL_SECTION_START
      block_buffer_runtime_us += segment_time_us;
    CRITICAL_SECTION_END
  #endif

  block->nominal_speed = block->millimeters * inverse_secs;           //   (mm/sec) Always > 0
  block->nominal_rate = CEIL(block->step_event_count * inverse_secs); // (step/sec) Always > 0

  #if ENABLED(FILAMENT_WIDTH_SENSOR)
    static float filwidth_e_count = 0, filwidth_delay_dist = 0;

    //FMM update ring buffer used for delay with filament measurements
    if (extruder == FILAMENT_SENSOR_EXTRUDER_NUM && filwidth_delay_index[1] >= 0) {  //only for extruder with filament sensor and if ring buffer is initialized

      constexpr int MMD_CM = MAX_MEASUREMENT_DELAY + 1, MMD_MM = MMD_CM * 10;

      // increment counters with next move in e axis
      filwidth_e_count += delta_mm[E_AXIS];
      filwidth_delay_dist += delta_mm[E_AXIS];

      // Only get new measurements on forward E movement
      if (!UNEAR_ZERO(filwidth_e_count)) {

        // Loop the delay distance counter (modulus by the mm length)
        while (filwidth_delay_dist >= MMD_MM) filwidth_delay_dist -= MMD_MM;

        // Convert into an index into the measurement array
        filwidth_delay_index[0] = int8_t(filwidth_delay_dist * 0.1);

        // If the index has changed (must have gone forward)...
        if (filwidth_delay_index[0] != filwidth_delay_index[1]) {
          filwidth_e_count = 0; // Reset the E movement counter
          const int8_t meas_sample = thermalManager.widthFil_to_size_ratio();
          do {
            filwidth_delay_index[1] = (filwidth_delay_index[1] + 1) % MMD_CM; // The next unused slot
            measurement_delay[filwidth_delay_index[1]] = meas_sample;         // Store the measurement
          } while (filwidth_delay_index[0] != filwidth_delay_index[1]);       // More slots to fill?
        }
      }
    }
  #endif

  // Calculate and limit speed in mm/sec for each axis
  float current_speed[NUM_AXIS], speed_factor = 1.0; // factor <1 decreases speed
  LOOP_XYZE(i) {
    const float cs = FABS((current_speed[i] = delta_mm[i] * inverse_secs));
    #if ENABLED(DISTINCT_E_FACTORS)
      if (i == E_AXIS) i += extruder;
    #endif
    if (cs > max_feedrate_mm_s[i]) NOMORE(speed_factor, max_feedrate_mm_s[i] / cs);
  }

  // Max segment time in µs.
  #ifdef XY_FREQUENCY_LIMIT

    // Check and limit the xy direction change frequency
    const unsigned char direction_change = block->direction_bits ^ old_direction_bits;
    old_direction_bits = block->direction_bits;
    segment_time_us = LROUND((float)segment_time_us / speed_factor);

    uint32_t xs0 = axis_segment_time_us[X_AXIS][0],
             xs1 = axis_segment_time_us[X_AXIS][1],
             xs2 = axis_segment_time_us[X_AXIS][2],
             ys0 = axis_segment_time_us[Y_AXIS][0],
             ys1 = axis_segment_time_us[Y_AXIS][1],
             ys2 = axis_segment_time_us[Y_AXIS][2];

    if (TEST(direction_change, X_AXIS)) {
      xs2 = axis_segment_time_us[X_AXIS][2] = xs1;
      xs1 = axis_segment_time_us[X_AXIS][1] = xs0;
      xs0 = 0;
    }
    xs0 = axis_segment_time_us[X_AXIS][0] = xs0 + segment_time_us;

    if (TEST(direction_change, Y_AXIS)) {
      ys2 = axis_segment_time_us[Y_AXIS][2] = axis_segment_time_us[Y_AXIS][1];
      ys1 = axis_segment_time_us[Y_AXIS][1] = axis_segment_time_us[Y_AXIS][0];
      ys0 = 0;
    }
    ys0 = axis_segment_time_us[Y_AXIS][0] = ys0 + segment_time_us;

    const uint32_t max_x_segment_time = MAX3(xs0, xs1, xs2),
                   max_y_segment_time = MAX3(ys0, ys1, ys2),
                   min_xy_segment_time = min(max_x_segment_time, max_y_segment_time);
    if (min_xy_segment_time < MAX_FREQ_TIME_US) {
      const float low_sf = speed_factor * min_xy_segment_time / (MAX_FREQ_TIME_US);
      NOMORE(speed_factor, low_sf);
    }
  #endif // XY_FREQUENCY_LIMIT

  // Correct the speed
  if (speed_factor < 1.0) {
    LOOP_XYZE(i) current_speed[i] *= speed_factor;
    block->nominal_speed *= speed_factor;
    block->nominal_rate *= speed_factor;
  }

  // Compute and limit the acceleration rate for the trapezoid generator.
  const float steps_per_mm = block->step_event_count * inverse_millimeters;
  uint32_t accel;
  if (!block->steps[A_AXIS] && !block->steps[B_AXIS] && !block->steps[C_AXIS]) {
    // convert to: acceleration steps/sec^2
    accel = CEIL(retract_acceleration * steps_per_mm);
    #if ENABLED(LIN_ADVANCE)
      block->use_advance_lead = false;
    #endif
  }
  else {
    #define LIMIT_ACCEL_LONG(AXIS,INDX) do{ \
      if (block->steps[AXIS] && max_acceleration_steps_per_s2[AXIS+INDX] < accel) { \
        const uint32_t comp = max_acceleration_steps_per_s2[AXIS+INDX] * block->step_event_count; \
        if (accel * block->steps[AXIS] > comp) accel = comp / block->steps[AXIS]; \
      } \
    }while(0)

    #define LIMIT_ACCEL_FLOAT(AXIS,INDX) do{ \
      if (block->steps[AXIS] && max_acceleration_steps_per_s2[AXIS+INDX] < accel) { \
        const float comp = (float)max_acceleration_steps_per_s2[AXIS+INDX] * (float)block->step_event_count; \
        if ((float)accel * (float)block->steps[AXIS] > comp) accel = comp / (float)block->steps[AXIS]; \
      } \
    }while(0)

    // Start with print or travel acceleration
    accel = CEIL((esteps ? acceleration : travel_acceleration) * steps_per_mm);

    #if ENABLED(LIN_ADVANCE)
      /**
       *
       * Use LIN_ADVANCE for blocks if all these are true:
       *
       * esteps             : This is a print move, because we checked for A, B, C steps before.
       *
       * extruder_advance_K : There is an advance factor set.
       *
       * de > 0             : Extruder is running forward (e.g., for "Wipe while retracting" (Slic3r) or "Combing" (Cura) moves)
       */
      block->use_advance_lead =  esteps
                              && extruder_advance_K
                              && de > 0;

      if (block->use_advance_lead) {
        block->e_D_ratio = (target_float[E_AXIS] - position_float[E_AXIS]) /
          #if IS_KINEMATIC
            block->millimeters
          #else
            SQRT(sq(target_float[X_AXIS] - position_float[X_AXIS])
               + sq(target_float[Y_AXIS] - position_float[Y_AXIS])
               + sq(target_float[Z_AXIS] - position_float[Z_AXIS]))
          #endif
        ;

        // Check for unusual high e_D ratio to detect if a retract move was combined with the last print move due to min. steps per segment. Never execute this with advance!
        // This assumes no one will use a retract length of 0mm < retr_length < ~0.2mm and no one will print 100mm wide lines using 3mm filament or 35mm wide lines using 1.75mm filament.
        if (block->e_D_ratio > 3.0)
          block->use_advance_lead = false;
        else {
          const uint32_t max_accel_steps_per_s2 = max_jerk[E_AXIS] / (extruder_advance_K * block->e_D_ratio) * steps_per_mm;
          #if ENABLED(LA_DEBUG)
            if (accel > max_accel_steps_per_s2)
              SERIAL_ECHOLNPGM("Acceleration limited.");
          #endif
          NOMORE(accel, max_accel_steps_per_s2);
        }
      }
    #endif

    #if ENABLED(DISTINCT_E_FACTORS)
      #define ACCEL_IDX extruder
    #else
      #define ACCEL_IDX 0
    #endif

    // Limit acceleration per axis
    if (block->step_event_count <= cutoff_long) {
      LIMIT_ACCEL_LONG(A_AXIS, 0);
      LIMIT_ACCEL_LONG(B_AXIS, 0);
      LIMIT_ACCEL_LONG(C_AXIS, 0);
      LIMIT_ACCEL_LONG(E_AXIS, ACCEL_IDX);
    }
    else {
      LIMIT_ACCEL_FLOAT(A_AXIS, 0);
      LIMIT_ACCEL_FLOAT(B_AXIS, 0);
      LIMIT_ACCEL_FLOAT(C_AXIS, 0);
      LIMIT_ACCEL_FLOAT(E_AXIS, ACCEL_IDX);
    }
  }
  block->acceleration_steps_per_s2 = accel;
  block->acceleration = accel / steps_per_mm;
  #if DISABLED(BEZIER_JERK_CONTROL)
    block->acceleration_rate = (long)(accel * (4096.0 * 4096.0 / (HAL_STEPPER_TIMER_RATE)));
  #endif
  #if ENABLED(LIN_ADVANCE)
    if (block->use_advance_lead) {
      block->advance_speed = (HAL_STEPPER_TIMER_RATE) / (extruder_advance_K * block->e_D_ratio * block->acceleration * axis_steps_per_mm[E_AXIS_N]);
      #if ENABLED(LA_DEBUG)
        if (extruder_advance_K * block->e_D_ratio * block->acceleration * 2 < block->nominal_speed * block->e_D_ratio)
          SERIAL_ECHOLNPGM("More than 2 steps per eISR loop executed.");
        if (block->advance_speed < 200)
          SERIAL_ECHOLNPGM("eISR running at > 10kHz.");
      #endif
    }
  #endif

  float vmax_junction; // Initial limit on the segment entry velocity

  #if ENABLED(JUNCTION_DEVIATION)

    /**
     * Compute maximum allowable entry speed at junction by centripetal acceleration approximation.
     * Let a circle be tangent to both previous and current path line segments, where the junction 
     * deviation is defined as the distance from the junction to the closest edge of the circle, 
     * colinear with the circle center. The circular segment joining the two paths represents the 
     * path of centripetal acceleration. Solve for max velocity based on max acceleration about the
     * radius of the circle, defined indirectly by junction deviation. This may be also viewed as 
     * path width or max_jerk in the previous Grbl version. This approach does not actually deviate 
     * from path, but used as a robust way to compute cornering speeds, as it takes into account the
     * nonlinearities of both the junction angle and junction velocity.
     *
     * NOTE: If the junction deviation value is finite, Grbl executes the motions in an exact path 
     * mode (G61). If the junction deviation value is zero, Grbl will execute the motion in an exact
     * stop mode (G61.1) manner. In the future, if continuous mode (G64) is desired, the math here
     * is exactly the same. Instead of motioning all the way to junction point, the machine will
     * just follow the arc circle defined here. The Arduino doesn't have the CPU cycles to perform
     * a continuous mode path, but ARM-based microcontrollers most certainly do. 
     * 
     * NOTE: The max junction speed is a fixed value, since machine acceleration limits cannot be
     * changed dynamically during operation nor can the line move geometry. This must be kept in
     * memory in the event of a feedrate override changing the nominal speeds of blocks, which can 
     * change the overall maximum entry speed conditions of all blocks.
     */

    // Unit vector of previous path line segment
    static float previous_unit_vec[
      #if ENABLED(JUNCTION_DEVIATION_INCLUDE_E)
        XYZE
      #else
        XYZ
      #endif
    ];

    float unit_vec[] = {
      delta_mm[A_AXIS] * inverse_millimeters,
      delta_mm[B_AXIS] * inverse_millimeters,
      delta_mm[C_AXIS] * inverse_millimeters
      #if ENABLED(JUNCTION_DEVIATION_INCLUDE_E)
        , delta_mm[E_AXIS] * inverse_millimeters
      #endif
    };

    // Skip first block or when previous_nominal_speed is used as a flag for homing and offset cycles.
    if (moves_queued && !UNEAR_ZERO(previous_nominal_speed)) {
      // Compute cosine of angle between previous and current path. (prev_unit_vec is negative)
      // NOTE: Max junction velocity is computed without sin() or acos() by trig half angle identity.
      float junction_cos_theta = -previous_unit_vec[X_AXIS] * unit_vec[X_AXIS]
                                 -previous_unit_vec[Y_AXIS] * unit_vec[Y_AXIS]
                                 -previous_unit_vec[Z_AXIS] * unit_vec[Z_AXIS]
                                  #if ENABLED(JUNCTION_DEVIATION_INCLUDE_E)
                                    -previous_unit_vec[E_AXIS] * unit_vec[E_AXIS]
                                  #endif
                                ;

      // NOTE: Computed without any expensive trig, sin() or acos(), by trig half angle identity of cos(theta).
      if (junction_cos_theta > 0.999999) {
        // For a 0 degree acute junction, just set minimum junction speed.
        vmax_junction = MINIMUM_PLANNER_SPEED;
      }
      else {
        junction_cos_theta = max(junction_cos_theta, -0.999999); // Check for numerical round-off to avoid divide by zero.
        const float sin_theta_d2 = SQRT(0.5 * (1.0 - junction_cos_theta)); // Trig half angle identity. Always positive.

        // TODO: Technically, the acceleration used in calculation needs to be limited by the minimum of the
        // two junctions. However, this shouldn't be a significant problem except in extreme circumstances.
        vmax_junction = SQRT((block->acceleration * JUNCTION_DEVIATION_FACTOR * sin_theta_d2) / (1.0 - sin_theta_d2));
      }

      vmax_junction = MIN3(vmax_junction, block->nominal_speed, previous_nominal_speed);
    }
    else // Init entry speed to zero. Assume it starts from rest. Planner will correct this later.
      vmax_junction = 0.0;

    COPY(previous_unit_vec, unit_vec);

  #else // Classic Jerk Limiting

    /**
     * Adapted from Průša MKS firmware
     * https://github.com/prusa3d/Prusa-Firmware
     *
     * Start with a safe speed (from which the machine may halt to stop immediately).
     */

    // Exit speed limited by a jerk to full halt of a previous last segment
    static float previous_safe_speed;

    float safe_speed = block->nominal_speed;
    uint8_t limited = 0;
    LOOP_XYZE(i) {
      const float jerk = FABS(current_speed[i]), maxj = max_jerk[i];
      if (jerk > maxj) {
        if (limited) {
          const float mjerk = maxj * block->nominal_speed;
          if (jerk * safe_speed > mjerk) safe_speed = mjerk / jerk;
        }
        else {
          ++limited;
          safe_speed = maxj;
        }
      }
    }

    if (moves_queued && !UNEAR_ZERO(previous_nominal_speed)) {
      // Estimate a maximum velocity allowed at a joint of two successive segments.
      // If this maximum velocity allowed is lower than the minimum of the entry / exit safe velocities,
      // then the machine is not coasting anymore and the safe entry / exit velocities shall be used.

      // The junction velocity will be shared between successive segments. Limit the junction velocity to their minimum.
      // Pick the smaller of the nominal speeds. Higher speed shall not be achieved at the junction during coasting.
      vmax_junction = min(block->nominal_speed, previous_nominal_speed);

      // Factor to multiply the previous / current nominal velocities to get componentwise limited velocities.
      float v_factor = 1;
      limited = 0;

      // Now limit the jerk in all axes.
      const float smaller_speed_factor = vmax_junction / previous_nominal_speed;
      LOOP_XYZE(axis) {
        // Limit an axis. We have to differentiate: coasting, reversal of an axis, full stop.
        float v_exit = previous_speed[axis] * smaller_speed_factor,
              v_entry = current_speed[axis];
        if (limited) {
          v_exit *= v_factor;
          v_entry *= v_factor;
        }

        // Calculate jerk depending on whether the axis is coasting in the same direction or reversing.
        const float jerk = (v_exit > v_entry)
            ? //                                  coasting             axis reversal
              ( (v_entry > 0 || v_exit < 0) ? (v_exit - v_entry) : max(v_exit, -v_entry) )
            : // v_exit <= v_entry                coasting             axis reversal
              ( (v_entry < 0 || v_exit > 0) ? (v_entry - v_exit) : max(-v_exit, v_entry) );

        if (jerk > max_jerk[axis]) {
          v_factor *= max_jerk[axis] / jerk;
          ++limited;
        }
      }
      if (limited) vmax_junction *= v_factor;
      // Now the transition velocity is known, which maximizes the shared exit / entry velocity while
      // respecting the jerk factors, it may be possible, that applying separate safe exit / entry velocities will achieve faster prints.
      const float vmax_junction_threshold = vmax_junction * 0.99f;
      if (previous_safe_speed > vmax_junction_threshold && safe_speed > vmax_junction_threshold)
        vmax_junction = safe_speed;
    }
    else
      vmax_junction = safe_speed;
  
    previous_safe_speed = safe_speed;
  #endif // Classic Jerk Limiting

  // Max entry speed of this block equals the max exit speed of the previous block.
  block->max_entry_speed = vmax_junction;

  // Initialize block entry speed. Compute based on deceleration to user-defined MINIMUM_PLANNER_SPEED.
  const float v_allowable = max_allowable_speed(-block->acceleration, MINIMUM_PLANNER_SPEED, block->millimeters);
  // If stepper ISR is disabled, this indicates buffer_segment wants to add a split block.
  // In this case start with the max. allowed speed to avoid an interrupted first move.
  block->entry_speed = STEPPER_ISR_ENABLED() ? MINIMUM_PLANNER_SPEED : min(vmax_junction, v_allowable);

  // Initialize planner efficiency flags
  // Set flag if block will always reach maximum junction speed regardless of entry/exit speeds.
  // If a block can de/ac-celerate from nominal speed to zero within the length of the block, then
  // the current block and next block junction speeds are guaranteed to always be at their maximum
  // junction speeds in deceleration and acceleration, respectively. This is due to how the current
  // block nominal speed limits both the current and next maximum junction speeds. Hence, in both
  // the reverse and forward planners, the corresponding block junction speed will always be at the
  // the maximum junction speed and may always be ignored for any speed reduction checks.
  block->flag |= block->nominal_speed <= v_allowable ? BLOCK_FLAG_RECALCULATE | BLOCK_FLAG_NOMINAL_LENGTH : BLOCK_FLAG_RECALCULATE;

  // Update previous path unit_vector and nominal speed
  COPY(previous_speed, current_speed);
  previous_nominal_speed = block->nominal_speed;

  // Move buffer head
  block_buffer_head = next_buffer_head;

  // Update the position (only when a move was queued)
  static_assert(COUNT(target) > 1, "Parameter to _buffer_steps must be (&target)[XYZE]!");
  COPY(position, target);
  #if HAS_POSITION_FLOAT
    COPY(position_float, target_float);
  #endif

  recalculate();

} // _buffer_steps()

/**
 * Planner::buffer_sync_block
 * Add a block to the buffer that just updates the position
 */
void Planner::buffer_sync_block() {
  // Wait for the next available block
  uint8_t next_buffer_head;
  block_t * const block = get_next_free_block(next_buffer_head);

  block->flag = BLOCK_FLAG_SYNC_POSITION;

  block->steps[A_AXIS] = position[A_AXIS];
  block->steps[B_AXIS] = position[B_AXIS];
  block->steps[C_AXIS] = position[C_AXIS];
  block->steps[E_AXIS] = position[E_AXIS];

  #if ENABLED(LIN_ADVANCE)
    block->use_advance_lead = false;
  #endif

  block->nominal_speed   =
  block->entry_speed     =
  block->max_entry_speed =
  block->millimeters     =  
  block->acceleration    = 0;

  block->step_event_count          =
  block->nominal_rate              =
  block->initial_rate              =
  block->final_rate                =
  block->acceleration_steps_per_s2 =
  block->segment_time_us           = 0;

  block_buffer_head = next_buffer_head;
  stepper.wake_up();
} // buffer_sync_block()

/**
 * Planner::buffer_segment
 *
 * Add a new linear movement to the buffer in axis units.
 *
 * Leveling and kinematics should be applied ahead of calling this.
 *
 *  a,b,c,e     - target positions in mm and/or degrees
 *  fr_mm_s     - (target) speed of the move
 *  extruder    - target extruder
 *  millimeters - the length of the movement, if known
 */
void Planner::buffer_segment(const float &a, const float &b, const float &c, const float &e, const float &fr_mm_s, const uint8_t extruder, const float &millimeters/*=0.0*/) {
  // When changing extruders recalculate steps corresponding to the E position
  #if ENABLED(DISTINCT_E_FACTORS)
    if (last_extruder != extruder && axis_steps_per_mm[E_AXIS_N] != axis_steps_per_mm[E_AXIS + last_extruder]) {
      position[E_AXIS] = LROUND(position[E_AXIS] * axis_steps_per_mm[E_AXIS_N] * steps_to_mm[E_AXIS + last_extruder]);
      last_extruder = extruder;
    }
  #endif

  // The target position of the tool in absolute steps
  // Calculate target position in absolute steps
  const int32_t target[ABCE] = {
    LROUND(a * axis_steps_per_mm[A_AXIS]),
    LROUND(b * axis_steps_per_mm[B_AXIS]),
    LROUND(c * axis_steps_per_mm[C_AXIS]),
    LROUND(e * axis_steps_per_mm[E_AXIS_N])
  };

  #if HAS_POSITION_FLOAT
    const float target_float[XYZE] = { a, b, c, e };
  #endif

  // DRYRUN prevents E moves from taking place
  if (DEBUGGING(DRYRUN)) {
    position[E_AXIS] = target[E_AXIS];
    #if HAS_POSITION_FLOAT
      position_float[E_AXIS] = e;
    #endif
  }

  /* <-- add a slash to enable
    SERIAL_ECHOPAIR("  buffer_segment FR:", fr_mm_s);
    #if IS_KINEMATIC
      SERIAL_ECHOPAIR(" A:", a);
      SERIAL_ECHOPAIR(" (", position[A_AXIS]);
      SERIAL_ECHOPAIR("->", target[A_AXIS]);
      SERIAL_ECHOPAIR(") B:", b);
    #else
      SERIAL_ECHOPAIR(" X:", a);
      SERIAL_ECHOPAIR(" (", position[X_AXIS]);
      SERIAL_ECHOPAIR("->", target[X_AXIS]);
      SERIAL_ECHOPAIR(") Y:", b);
    #endif
    SERIAL_ECHOPAIR(" (", position[Y_AXIS]);
    SERIAL_ECHOPAIR("->", target[Y_AXIS]);
    #if ENABLED(DELTA)
      SERIAL_ECHOPAIR(") C:", c);
    #else
      SERIAL_ECHOPAIR(") Z:", c);
    #endif
    SERIAL_ECHOPAIR(" (", position[Z_AXIS]);
    SERIAL_ECHOPAIR("->", target[Z_AXIS]);
    SERIAL_ECHOPAIR(") E:", e);
    SERIAL_ECHOPAIR(" (", position[E_AXIS]);
    SERIAL_ECHOPAIR("->", target[E_AXIS]);
    SERIAL_ECHOLNPGM(")");
  //*/

  // Always split the first move into two (if not homing or probing)
  if (!has_blocks_queued()) {

    #define _BETWEEN(A) (position[A##_AXIS] + target[A##_AXIS]) >> 1
    const int32_t between[ABCE] = { _BETWEEN(A), _BETWEEN(B), _BETWEEN(C), _BETWEEN(E) };

    #if HAS_POSITION_FLOAT
      #define _BETWEEN_F(A) (position_float[A##_AXIS] + target_float[A##_AXIS]) * 0.5
      const float between_float[ABCE] = { _BETWEEN_F(A), _BETWEEN_F(B), _BETWEEN_F(C), _BETWEEN_F(E) };
    #endif

    DISABLE_STEPPER_DRIVER_INTERRUPT();

    _buffer_steps(between
      #if HAS_POSITION_FLOAT
        , between_float
      #endif
      , fr_mm_s, extruder, millimeters * 0.5
    );

    const uint8_t next = block_buffer_head;

    _buffer_steps(target
      #if HAS_POSITION_FLOAT
        , target_float
      #endif
      , fr_mm_s, extruder, millimeters * 0.5
    );

    SBI(block_buffer[next].flag, BLOCK_BIT_CONTINUED);
    ENABLE_STEPPER_DRIVER_INTERRUPT();
  }
  else
    _buffer_steps(target
      #if HAS_POSITION_FLOAT
        , target_float
      #endif
      , fr_mm_s, extruder, millimeters
    );

  stepper.wake_up();

} // buffer_segment()

/**
 * Directly set the planner XYZ position (and stepper positions)
 * converting mm (or angles for SCARA) into steps.
 *
 * On CORE machines stepper ABC will be translated from the given XYZ.
 */

void Planner::_set_position_mm(const float &a, const float &b, const float &c, const float &e) {
  #if ENABLED(DISTINCT_E_FACTORS)
    #define _EINDEX (E_AXIS + active_extruder)
    last_extruder = active_extruder;
  #else
    #define _EINDEX E_AXIS
  #endif
  position[A_AXIS] = LROUND(a * axis_steps_per_mm[A_AXIS]),
  position[B_AXIS] = LROUND(b * axis_steps_per_mm[B_AXIS]),
  position[C_AXIS] = LROUND(c * axis_steps_per_mm[C_AXIS]),
  position[E_AXIS] = LROUND(e * axis_steps_per_mm[_EINDEX]);
  #if HAS_POSITION_FLOAT
    position_float[A_AXIS] = a;
    position_float[B_AXIS] = b;
    position_float[C_AXIS] = c;
    position_float[E_AXIS] = e;
  #endif
  previous_nominal_speed = 0.0; // Resets planner junction speeds. Assumes start from rest.
  ZERO(previous_speed);
  buffer_sync_block();
}

void Planner::set_position_mm_kinematic(const float (&cart)[XYZE]) {
  #if PLANNER_LEVELING
    float raw[XYZ] = { cart[X_AXIS], cart[Y_AXIS], cart[Z_AXIS] };
    apply_leveling(raw);
  #else
    const float (&raw)[XYZE] = cart;
  #endif
  #if IS_KINEMATIC
    inverse_kinematics(raw);
    _set_position_mm(delta[A_AXIS], delta[B_AXIS], delta[C_AXIS], cart[E_AXIS]);
  #else
    _set_position_mm(raw[X_AXIS], raw[Y_AXIS], raw[Z_AXIS], cart[E_AXIS]);
  #endif
}

/**
 * Sync from the stepper positions. (e.g., after an interrupted move)
 */
void Planner::sync_from_steppers() {
  LOOP_XYZE(i) {
    position[i] = stepper.position((AxisEnum)i);
    #if HAS_POSITION_FLOAT
      position_float[i] = position[i] * steps_to_mm[i
        #if ENABLED(DISTINCT_E_FACTORS)
          + (i == E_AXIS ? active_extruder : 0)
        #endif
      ];
    #endif
  }
}

/**
 * Setters for planner position (also setting stepper position).
 */
void Planner::set_position_mm(const AxisEnum axis, const float &v) {
  #if ENABLED(DISTINCT_E_FACTORS)
    const uint8_t axis_index = axis + (axis == E_AXIS ? active_extruder : 0);
    last_extruder = active_extruder;
  #else
    const uint8_t axis_index = axis;
  #endif
  position[axis] = LROUND(v * axis_steps_per_mm[axis_index]);
  #if HAS_POSITION_FLOAT
    position_float[axis] = v;
  #endif
  previous_speed[axis] = 0.0;
  buffer_sync_block();
}

// Recalculate the steps/s^2 acceleration rates, based on the mm/s^2
void Planner::reset_acceleration_rates() {
  #if ENABLED(DISTINCT_E_FACTORS)
    #define AXIS_CONDITION (i < E_AXIS || i == E_AXIS + active_extruder)
  #else
    #define AXIS_CONDITION true
  #endif
  uint32_t highest_rate = 1;
  LOOP_XYZE_N(i) {
    max_acceleration_steps_per_s2[i] = max_acceleration_mm_per_s2[i] * axis_steps_per_mm[i];
    if (AXIS_CONDITION) NOLESS(highest_rate, max_acceleration_steps_per_s2[i]);
  }
  cutoff_long = 4294967295UL / highest_rate; // 0xFFFFFFFFUL
}

// Recalculate position, steps_to_mm if axis_steps_per_mm changes!
void Planner::refresh_positioning() {
  LOOP_XYZE_N(i) steps_to_mm[i] = 1.0 / axis_steps_per_mm[i];
  set_position_mm_kinematic(current_position);
  reset_acceleration_rates();
}

#if ENABLED(AUTOTEMP)

  void Planner::autotemp_M104_M109() {
    if ((autotemp_enabled = parser.seen('F'))) autotemp_factor = parser.value_float();
    if (parser.seen('S')) autotemp_min = parser.value_celsius();
    if (parser.seen('B')) autotemp_max = parser.value_celsius();
  }

#endif