Cleanup of planner code

- Use named axis indexes, `X_AXIS` etc. - Replace `block.steps_A` with block.steps[A]` - Replace `A_segment_time` with `segment_time[A]` - Add `A_AXIS`, `B_AXIS` for `COREXY` axes - Conditional compile based on `EXTRUDERS` - Add BLOCK_MOD macro for planner block indexes - Apply coding standards to `planner.h` and `planner.cpp` - Small optimizations of planner code - Update `stepper.cpp` for new `block` struct - Replace `memcpy` with loops, let the compiler unroll them - Make `movesplanned` into an inline function
10 years ago · 13fbf42d95
parent 0d869703ca
commit 13fbf42d95
4 changed files with 616 additions and 754 deletions
--- a/Marlin/Marlin.h
+++ b/Marlin/Marlin.h
@ -183,7 +183,7 @@ void manage_inactivity(bool ignore_stepper_queue=false);
  #define disable_e3() /* nothing */
 #endif

-enum AxisEnum {X_AXIS=0, Y_AXIS=1, Z_AXIS=2, E_AXIS=3, X_HEAD=4, Y_HEAD=5}; 
+enum AxisEnum {X_AXIS=0, Y_AXIS=1, A_AXIS=0, B_AXIS=1, Z_AXIS=2, E_AXIS=3, X_HEAD=4, Y_HEAD=5};
 //X_HEAD and Y_HEAD is used for systems that don't have a 1:1 relationship between X_AXIS and X Head movement, like CoreXY bots.

 void FlushSerialRequestResend();
@ -270,7 +270,7 @@ extern unsigned char fanSpeedSoftPwm;
  extern bool filament_sensor;  //indicates that filament sensor readings should control extrusion
  extern float filament_width_meas; //holds the filament diameter as accurately measured
  extern signed char measurement_delay[];  //ring buffer to delay measurement
-  extern int delay_index1, delay_index2;  //index into ring buffer
+  extern int delay_index1, delay_index2;  //ring buffer index. used by planner, temperature, and main code
  extern float delay_dist; //delay distance counter
  extern int meas_delay_cm; //delay distance
 #endif
--- a/Marlin/planner.cpp
+++ b/Marlin/planner.cpp
@ -113,52 +113,32 @@ volatile unsigned char block_buffer_tail;           // Index of the block to pro
  float extrude_min_temp = EXTRUDE_MINTEMP;
 #endif
 #ifdef XY_FREQUENCY_LIMIT
-#define MAX_FREQ_TIME (1000000.0/XY_FREQUENCY_LIMIT)
  // Used for the frequency limit
-static unsigned char old_direction_bits = 0;               // Old direction bits. Used for speed calculations
-static long x_segment_time[3]={MAX_FREQ_TIME + 1,0,0};     // Segment times (in us). Used for speed calculations
-static long y_segment_time[3]={MAX_FREQ_TIME + 1,0,0};
+  #define MAX_FREQ_TIME (1000000.0/XY_FREQUENCY_LIMIT)
+  // Old direction bits. Used for speed calculations
+  static unsigned char old_direction_bits = 0;
+  // Segment times (in µs). Used for speed calculations
+  static long axis_segment_time[2][3] = { {MAX_FREQ_TIME+1,0,0}, {MAX_FREQ_TIME+1,0,0} };
 #endif

 #ifdef FILAMENT_SENSOR
  static char meas_sample; //temporary variable to hold filament measurement sample
 #endif

-// Returns the index of the next block in the ring buffer
-// NOTE: Removed modulo (%) operator, which uses an expensive divide and multiplication.
-static int8_t next_block_index(int8_t block_index) {
-  block_index++;
-  if (block_index == BLOCK_BUFFER_SIZE) { 
-    block_index = 0; 
-  }
-  return(block_index);
-}
-
-
-// Returns the index of the previous block in the ring buffer
-static int8_t prev_block_index(int8_t block_index) {
-  if (block_index == 0) { 
-    block_index = BLOCK_BUFFER_SIZE; 
-  }
-  block_index--;
-  return(block_index);
-}
+// Get the next / previous index of the next block in the ring buffer
+// NOTE: Using & here (not %) because BLOCK_BUFFER_SIZE is always a power of 2
+FORCE_INLINE int8_t next_block_index(int8_t block_index) { return BLOCK_MOD(block_index + 1); }
+FORCE_INLINE int8_t prev_block_index(int8_t block_index) { return BLOCK_MOD(block_index - 1); }

 //===========================================================================
-//=============================functions         ============================
+//================================ Functions ================================
 //===========================================================================

 // Calculates the distance (not time) it takes to accelerate from initial_rate to target_rate using the 
 // given acceleration:
-FORCE_INLINE float estimate_acceleration_distance(float initial_rate, float target_rate, float acceleration)
-{
-  if (acceleration!=0) {
-    return((target_rate*target_rate-initial_rate*initial_rate)/
-      (2.0*acceleration));
-  }
-  else {
-    return 0.0;  // acceleration was 0, set acceleration distance to 0
-  }
+FORCE_INLINE float estimate_acceleration_distance(float initial_rate, float target_rate, float acceleration) {
+  if (acceleration == 0) return 0; // acceleration was 0, set acceleration distance to 0
+  return (target_rate * target_rate - initial_rate * initial_rate) / (acceleration * 2);
 }

 // This function gives you the point at which you must start braking (at the rate of -acceleration) if 
@ -166,15 +146,9 @@ FORCE_INLINE float estimate_acceleration_distance(float initial_rate, float targ
 // a total travel of distance. This can be used to compute the intersection point between acceleration and
 // deceleration in the cases where the trapezoid has no plateau (i.e. never reaches maximum speed)

-FORCE_INLINE float intersection_distance(float initial_rate, float final_rate, float acceleration, float distance) 
-{
-  if (acceleration!=0) {
-    return((2.0*acceleration*distance-initial_rate*initial_rate+final_rate*final_rate)/
-      (4.0*acceleration) );
-  }
-  else {
-    return 0.0;  // acceleration was 0, set intersection distance to 0
-  }
+FORCE_INLINE float intersection_distance(float initial_rate, float final_rate, float acceleration, float distance) {
+  if (acceleration == 0) return 0; // acceleration was 0, set intersection distance to 0
+  return (acceleration * 2 * distance - initial_rate * initial_rate + final_rate * final_rate) / (acceleration * 4);
 }

 // Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
@ -184,18 +158,12 @@ void calculate_trapezoid_for_block(block_t *block, float entry_factor, float exi
  unsigned long final_rate = ceil(block->nominal_rate * exit_factor); // (step/min)

  // Limit minimal step rate (Otherwise the timer will overflow.)
-  if(initial_rate <120) {
-    initial_rate=120; 
-  }
-  if(final_rate < 120) {
-    final_rate=120;  
-  }
+  if (initial_rate < 120) initial_rate = 120;
+  if (final_rate < 120) final_rate = 120;

  long acceleration = block->acceleration_st;
-  int32_t accelerate_steps =
-    ceil(estimate_acceleration_distance(initial_rate, block->nominal_rate, acceleration));
-  int32_t decelerate_steps =
-    floor(estimate_acceleration_distance(block->nominal_rate, final_rate, -acceleration));
+  int32_t accelerate_steps = ceil(estimate_acceleration_distance(initial_rate, block->nominal_rate, acceleration));
+  int32_t decelerate_steps = floor(estimate_acceleration_distance(block->nominal_rate, final_rate, -acceleration));

  // Calculate the size of Plateau of Nominal Rate.
  int32_t plateau_steps = block->step_event_count - accelerate_steps - decelerate_steps;
@ -218,7 +186,7 @@ void calculate_trapezoid_for_block(block_t *block, float entry_factor, float exi
  // block->accelerate_until = accelerate_steps;
  // block->decelerate_after = accelerate_steps+plateau_steps;
  CRITICAL_SECTION_START;  // Fill variables used by the stepper in a critical section
-  if(block->busy == false) { // Don't update variables if block is busy.
+  if (!block->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;
@ -226,7 +194,7 @@ void calculate_trapezoid_for_block(block_t *block, float entry_factor, float exi
    #ifdef ADVANCE
      block->initial_advance = initial_advance;
      block->final_advance = final_advance;
-#endif //ADVANCE
+    #endif
  }
  CRITICAL_SECTION_END;
 }                    
@ -248,9 +216,7 @@ FORCE_INLINE float max_allowable_speed(float acceleration, float target_velocity

 // The kernel called by planner_recalculate() when scanning the plan from last to first entry.
 void planner_reverse_pass_kernel(block_t *previous, block_t *current, block_t *next) {
-  if(!current) { 
-    return; 
-  }
+  if (!current) return;

  if (next) {
    // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
@ -260,7 +226,7 @@ void planner_reverse_pass_kernel(block_t *previous, block_t *current, block_t *n

      // 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.
-      if ((!current->nominal_length_flag) && (current->max_entry_speed > next->entry_speed)) {
+      if (!current->nominal_length_flag && current->max_entry_speed > next->entry_speed) {
        current->entry_speed = min(current->max_entry_speed,
          max_allowable_speed(-current->acceleration, next->entry_speed, current->millimeters));
      } 
@ -283,10 +249,9 @@ void planner_reverse_pass() {
    unsigned char tail = block_buffer_tail;
  CRITICAL_SECTION_END
  
-  if(((block_buffer_head-tail + BLOCK_BUFFER_SIZE) & (BLOCK_BUFFER_SIZE - 1)) > 3) {
-    block_index = (block_buffer_head - 3) & (BLOCK_BUFFER_SIZE - 1);
-    block_t *block[3] = { 
-      NULL, NULL, NULL         };
+  if (BLOCK_MOD(block_buffer_head - tail + BLOCK_BUFFER_SIZE) > 3) { // moves queued
+    block_index = BLOCK_MOD(block_buffer_head - 3);
+    block_t *block[3] = { NULL, NULL, NULL };
    while (block_index != tail) {
      block_index = prev_block_index(block_index);
      block[2]= block[1];
@ -299,9 +264,7 @@ void planner_reverse_pass() {

 // The kernel called by planner_recalculate() when scanning the plan from first to last entry.
 void planner_forward_pass_kernel(block_t *previous, block_t *current, block_t *next) {
-  if(!previous) { 
-    return; 
-  }
+  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
@ -325,8 +288,7 @@ void planner_forward_pass_kernel(block_t *previous, block_t *current, block_t *n
 // implements the forward pass.
 void planner_forward_pass() {
  uint8_t block_index = block_buffer_tail;
-  block_t *block[3] = { 
-    NULL, NULL, NULL   };
+  block_t *block[3] = { NULL, NULL, NULL };

  while (block_index != block_buffer_head) {
    block[0] = block[1];
@ -353,7 +315,8 @@ void planner_recalculate_trapezoids() {
      // Recalculate if current block entry or exit junction speed has changed.
      if (current->recalculate_flag || next->recalculate_flag) {
        // NOTE: Entry and exit factors always > 0 by all previous logic operations.
-        calculate_trapezoid_for_block(current, current->entry_speed/current->nominal_speed,
+        calculate_trapezoid_for_block(current,
+          current->entry_speed / current->nominal_speed,
          next->entry_speed / current->nominal_speed);
        current->recalculate_flag = false; // Reset current only to ensure next trapezoid is computed
      }
@ -361,7 +324,7 @@ void planner_recalculate_trapezoids() {
    block_index = next_block_index( block_index );
  }
  // Last/newest block in buffer. Exit speed is set with MINIMUM_PLANNER_SPEED. Always recalculated.
-  if(next != NULL) {
+  if (next) {
    calculate_trapezoid_for_block(next, next->entry_speed/next->nominal_speed,
    MINIMUM_PLANNER_SPEED/next->nominal_speed);
    next->recalculate_flag = false;
@ -392,104 +355,76 @@ void planner_recalculate() {
 }

 void plan_init() {
-  block_buffer_head = 0;
-  block_buffer_tail = 0;
+  block_buffer_head = block_buffer_tail = 0;
  memset(position, 0, sizeof(position)); // clear position
-  previous_speed[0] = 0.0;
-  previous_speed[1] = 0.0;
-  previous_speed[2] = 0.0;
-  previous_speed[3] = 0.0;
+  for (int i=0; i<NUM_AXIS; i++) previous_speed[i] = 0.0; 
  previous_nominal_speed = 0.0;
 }


-
-
 #ifdef AUTOTEMP
-void getHighESpeed()
-{
+  void getHighESpeed() {
    static float oldt = 0;
-  if(!autotemp_enabled){
-    return;
-  }
-  if(degTargetHotend0()+2<autotemp_min) {  //probably temperature set to zero.
-    return; //do nothing
-  }
+
+    if (!autotemp_enabled) return;
+    if (degTargetHotend0() + 2 < autotemp_min) return; // probably temperature set to zero.

    float high = 0.0;
    uint8_t block_index = block_buffer_tail;

    while (block_index != block_buffer_head) {
-    if((block_buffer[block_index].steps_x != 0) ||
-      (block_buffer[block_index].steps_y != 0) ||
-      (block_buffer[block_index].steps_z != 0)) {
-      float se=(float(block_buffer[block_index].steps_e)/float(block_buffer[block_index].step_event_count))*block_buffer[block_index].nominal_speed;
+      if ((block_buffer[block_index].steps[X_AXIS] != 0) ||
+          (block_buffer[block_index].steps[Y_AXIS] != 0) ||
+          (block_buffer[block_index].steps[Z_AXIS] != 0)) {
+        float se=(float(block_buffer[block_index].steps[E_AXIS])/float(block_buffer[block_index].step_event_count))*block_buffer[block_index].nominal_speed;
        //se; mm/sec;
-      if(se>high)
-      {
-        high=se;
-      }
+        if (se > high) high = se;
      }
-    block_index = (block_index+1) & (BLOCK_BUFFER_SIZE - 1);
+      block_index = next_block_index(block_index);
    }

-  float g=autotemp_min+high*autotemp_factor;
-  float t=g;
-  if(t<autotemp_min)
-    t=autotemp_min;
-  if(t>autotemp_max)
-    t=autotemp_max;
-  if(oldt>t)
-  {
-    t=AUTOTEMP_OLDWEIGHT*oldt+(1-AUTOTEMP_OLDWEIGHT)*t;
-  }
+    float t = autotemp_min + high * autotemp_factor;
+    if (t < autotemp_min) t = autotemp_min;
+    if (t > autotemp_max) t = autotemp_max;
+    if (oldt > t) t = AUTOTEMP_OLDWEIGHT * oldt + (1 - AUTOTEMP_OLDWEIGHT) * t;
    oldt = t;
    setTargetHotend0(t);
  }
 #endif

-void check_axes_activity()
-{
-  unsigned char x_active = 0;
-  unsigned char y_active = 0;  
-  unsigned char z_active = 0;
-  unsigned char e_active = 0;
-  unsigned char tail_fan_speed = fanSpeed;
+void check_axes_activity() {
+  unsigned char axis_active[NUM_AXIS],
+                tail_fan_speed = fanSpeed;
  #ifdef BARICUDA
-  unsigned char tail_valve_pressure = ValvePressure;
-  unsigned char tail_e_to_p_pressure = EtoPPressure;
+    unsigned char tail_valve_pressure = ValvePressure,
+                  tail_e_to_p_pressure = EtoPPressure;
  #endif
  block_t *block;

-  if(block_buffer_tail != block_buffer_head)
-  {
+  if (blocks_queued()) {
    uint8_t block_index = block_buffer_tail;
    tail_fan_speed = block_buffer[block_index].fan_speed;
    #ifdef BARICUDA
      tail_valve_pressure = block_buffer[block_index].valve_pressure;
      tail_e_to_p_pressure = block_buffer[block_index].e_to_p_pressure;
    #endif
-    while(block_index != block_buffer_head)
-    {
+    while (block_index != block_buffer_head) {
      block = &block_buffer[block_index];
-      if(block->steps_x != 0) x_active++;
-      if(block->steps_y != 0) y_active++;
-      if(block->steps_z != 0) z_active++;
-      if(block->steps_e != 0) e_active++;
-      block_index = (block_index+1) & (BLOCK_BUFFER_SIZE - 1);
+      for (int i=0; i<NUM_AXIS; i++) if (block->steps[i]) axis_active[i]++;
+      block_index = next_block_index(block_index);
    }
  }
-  if((DISABLE_X) && (x_active == 0)) disable_x();
-  if((DISABLE_Y) && (y_active == 0)) disable_y();
-  if((DISABLE_Z) && (z_active == 0)) disable_z();
-  if((DISABLE_E) && (e_active == 0))
-  {
+  if (DISABLE_X && !axis_active[X_AXIS]) disable_x();
+  if (DISABLE_Y && !axis_active[Y_AXIS]) disable_y();
+  if (DISABLE_Z && !axis_active[Z_AXIS]) disable_z();
+  if (DISABLE_E && !axis_active[E_AXIS]) {
    disable_e0();
    disable_e1();
    disable_e2();
    disable_e3();
  }
-#if defined(FAN_PIN) && FAN_PIN > -1
+
+  #if defined(FAN_PIN) && FAN_PIN > -1 // HAS_FAN
    #ifdef FAN_KICKSTART_TIME
      static unsigned long fan_kick_end;
      if (tail_fan_speed) {
@ -510,16 +445,16 @@ void check_axes_activity()
      analogWrite(FAN_PIN, tail_fan_speed);
    #endif //!FAN_SOFT_PWM
  #endif //FAN_PIN > -1
+
  #ifdef AUTOTEMP
    getHighESpeed();
  #endif

  #ifdef BARICUDA
-  #if defined(HEATER_1_PIN) && HEATER_1_PIN > -1
+    #if defined(HEATER_1_PIN) && HEATER_1_PIN > -1 // HAS_HEATER_1
      analogWrite(HEATER_1_PIN,tail_valve_pressure);
    #endif
-
-  #if defined(HEATER_2_PIN) && HEATER_2_PIN > -1
+    #if defined(HEATER_2_PIN) && HEATER_2_PIN > -1 // HAS_HEATER_2
      analogWrite(HEATER_2_PIN,tail_e_to_p_pressure);
    #endif
  #endif
@ -527,7 +462,7 @@ void check_axes_activity()


 float junction_deviation = 0.1;
-// Add a new linear movement to the buffer. steps_x, _y and _z is the absolute position in 
+// Add a new linear movement to the buffer. steps[X_AXIS], _y and _z is the absolute position in 
 // mm. Microseconds specify how many microseconds the move should take to perform. To aid acceleration
 // calculation the caller must also provide the physical length of the line in millimeters.
 #ifdef ENABLE_AUTO_BED_LEVELING
@ -541,8 +476,7 @@ void plan_buffer_line(const float &x, const float &y, const float &z, const floa

  // If the buffer is full: good! That means we are well ahead of the robot. 
  // Rest here until there is room in the buffer.
-  while(block_buffer_tail == next_buffer_head)
-  {
+  while(block_buffer_tail == next_buffer_head) {
    manage_heater(); 
    manage_inactivity(); 
    lcd_update();
@ -550,31 +484,32 @@ void plan_buffer_line(const float &x, const float &y, const float &z, const floa

  #ifdef ENABLE_AUTO_BED_LEVELING
    apply_rotation_xyz(plan_bed_level_matrix, x, y, z);
-#endif // ENABLE_AUTO_BED_LEVELING
+  #endif

  // The target position of the tool in absolute steps
  // Calculate target position in absolute steps
  //this should be done after the wait, because otherwise a M92 code within the gcode disrupts this calculation somehow
-  long target[4];
+  long target[NUM_AXIS];
  target[X_AXIS] = lround(x * axis_steps_per_unit[X_AXIS]);
  target[Y_AXIS] = lround(y * axis_steps_per_unit[Y_AXIS]);
  target[Z_AXIS] = lround(z * axis_steps_per_unit[Z_AXIS]);     
  target[E_AXIS] = lround(e * axis_steps_per_unit[E_AXIS]);

+  float dx = target[X_AXIS] - position[X_AXIS],
+        dy = target[Y_AXIS] - position[Y_AXIS],
+        dz = target[Z_AXIS] - position[Z_AXIS],
+        de = target[E_AXIS] - position[E_AXIS];
+
  #ifdef PREVENT_DANGEROUS_EXTRUDE
-  if(target[E_AXIS]!=position[E_AXIS])
-  {
-    if(degHotend(active_extruder)<extrude_min_temp)
-    {
+    if (de) {
+      if (degHotend(active_extruder) < extrude_min_temp) {
        position[E_AXIS] = target[E_AXIS]; //behave as if the move really took place, but ignore E part
        SERIAL_ECHO_START;
        SERIAL_ECHOLNPGM(MSG_ERR_COLD_EXTRUDE_STOP);
      }
-    
      #ifdef PREVENT_LENGTHY_EXTRUDE
-    if(labs(target[E_AXIS]-position[E_AXIS])>axis_steps_per_unit[E_AXIS]*EXTRUDE_MAXLENGTH)
-    {
-      position[E_AXIS]=target[E_AXIS]; //behave as if the move really took place, but ignore E part
+        if (labs(de) > axis_steps_per_unit[E_AXIS] * EXTRUDE_MAXLENGTH) {
+          position[E_AXIS] = target[E_AXIS]; // Behave as if the move really took place, but ignore E part
          SERIAL_ECHO_START;
          SERIAL_ECHOLNPGM(MSG_ERR_LONG_EXTRUDE_STOP);
        }
@ -589,28 +524,26 @@ void plan_buffer_line(const float &x, const float &y, const float &z, const floa
  block->busy = false;

  // Number of steps for each axis
-#ifndef COREXY
-// default non-h-bot planning
-block->steps_x = labs(target[X_AXIS]-position[X_AXIS]);
-block->steps_y = labs(target[Y_AXIS]-position[Y_AXIS]);
-#else
+  #ifdef COREXY
    // corexy planning
    // these equations follow the form of the dA and dB equations on http://www.corexy.com/theory.html
-block->steps_x = labs((target[X_AXIS]-position[X_AXIS]) + (target[Y_AXIS]-position[Y_AXIS]));
-block->steps_y = labs((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-position[Y_AXIS]));
+    block->steps[A_AXIS] = labs(dx + dy);
+    block->steps[B_AXIS] = labs(dx - dy);
+  #else
+    // default non-h-bot planning
+    block->steps[X_AXIS] = labs(dx);
+    block->steps[Y_AXIS] = labs(dy);
  #endif
-  block->steps_z = labs(target[Z_AXIS]-position[Z_AXIS]);
-  block->steps_e = labs(target[E_AXIS]-position[E_AXIS]);
-  block->steps_e *= volumetric_multiplier[active_extruder];
-  block->steps_e *= extrudemultiply;
-  block->steps_e /= 100;
-  block->step_event_count = max(block->steps_x, max(block->steps_y, max(block->steps_z, block->steps_e)));
+
+  block->steps[Z_AXIS] = labs(dz);
+  block->steps[E_AXIS] = labs(de);
+  block->steps[E_AXIS] *= volumetric_multiplier[active_extruder];
+  block->steps[E_AXIS] *= extrudemultiply;
+  block->steps[E_AXIS] /= 100;
+  block->step_event_count = max(block->steps[X_AXIS], max(block->steps[Y_AXIS], max(block->steps[Z_AXIS], block->steps[E_AXIS])));

  // Bail if this is a zero-length block
-  if (block->step_event_count <= dropsegments)
-  { 
-    return; 
-  }
+  if (block->step_event_count <= dropsegments) return;

  block->fan_speed = fanSpeed;
  #ifdef BARICUDA
@ -619,109 +552,94 @@ block->steps_y = labs((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-positi
  #endif

  // Compute direction bits for this block 
-  block->direction_bits = 0;
-#ifndef COREXY
-  if (target[X_AXIS] < position[X_AXIS])
-  {
-    block->direction_bits |= BIT(X_AXIS); 
-  }
-  if (target[Y_AXIS] < position[Y_AXIS])
-  {
-    block->direction_bits |= BIT(Y_AXIS); 
-  }
+  uint8_t db = 0;
+  #ifdef COREXY
+    if (dx < 0) db |= BIT(X_HEAD); // Save the real Extruder (head) direction in X Axis
+    if (dy < 0) db |= BIT(Y_HEAD); // ...and Y
+    if (dx + dy < 0) db |= BIT(A_AXIS); // Motor A direction
+    if (dx - dy < 0) db |= BIT(B_AXIS); // Motor B direction
  #else
-  if (target[X_AXIS] < position[X_AXIS])
-  {
-    block->direction_bits |= BIT(X_HEAD); //AlexBorro: Save the real Extruder (head) direction in X Axis
-  }
-  if (target[Y_AXIS] < position[Y_AXIS])
-  {
-    block->direction_bits |= BIT(Y_HEAD); //AlexBorro: Save the real Extruder (head) direction in Y Axis
-  }
-  if ((target[X_AXIS]-position[X_AXIS]) + (target[Y_AXIS]-position[Y_AXIS]) < 0)
-  {
-    block->direction_bits |= BIT(X_AXIS); //AlexBorro: Motor A direction (Incorrectly implemented as X_AXIS)
-  }
-  if ((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-position[Y_AXIS]) < 0)
-  {
-    block->direction_bits |= BIT(Y_AXIS); //AlexBorro: Motor B direction (Incorrectly implemented as Y_AXIS)
-  }
+    if (dx < 0) db |= BIT(X_AXIS);
+    if (dy < 0) db |= BIT(Y_AXIS); 
  #endif
-  if (target[Z_AXIS] < position[Z_AXIS])
-  {
-    block->direction_bits |= BIT(Z_AXIS); 
-  }
-  if (target[E_AXIS] < position[E_AXIS])
-  {
-    block->direction_bits |= BIT(E_AXIS); 
-  }
+  if (dz < 0) db |= BIT(Z_AXIS);
+  if (de < 0) db |= BIT(E_AXIS); 
+  block->direction_bits = db;

  block->active_extruder = extruder;

  //enable active axes
  #ifdef COREXY
-  if((block->steps_x != 0) || (block->steps_y != 0))
-  {
+    if (block->steps[A_AXIS] || block->steps[B_AXIS]) {
      enable_x();
      enable_y();
    }
  #else
-  if(block->steps_x != 0) enable_x();
-  if(block->steps_y != 0) enable_y();
+    if (block->steps[X_AXIS]) enable_x();
+    if (block->steps[Y_AXIS]) enable_y();
  #endif
+
  #ifndef Z_LATE_ENABLE
-  if(block->steps_z != 0) enable_z();
+    if (block->steps[Z_AXIS]) enable_z();
  #endif

  // Enable extruder(s)
-  if(block->steps_e != 0)
-  {
-    if (DISABLE_INACTIVE_EXTRUDER) //enable only selected extruder
-    {
+  if (block->steps[E_AXIS]) {
+    if (DISABLE_INACTIVE_EXTRUDER) { //enable only selected extruder

-      if(g_uc_extruder_last_move[0] > 0) g_uc_extruder_last_move[0]--;
-      if(g_uc_extruder_last_move[1] > 0) g_uc_extruder_last_move[1]--;
-      if(g_uc_extruder_last_move[2] > 0) g_uc_extruder_last_move[2]--;
-      if(g_uc_extruder_last_move[3] > 0) g_uc_extruder_last_move[3]--;
+      for (int i=0; i<EXTRUDERS; i++)
+        if (g_uc_extruder_last_move[i] > 0) g_uc_extruder_last_move[i]--;
      
-      switch(extruder)
-      {
+      switch(extruder) {
        case 0:
          enable_e0();
          g_uc_extruder_last_move[0] = BLOCK_BUFFER_SIZE * 2;
-          
+          #if EXTRUDERS > 1
            if (g_uc_extruder_last_move[1] == 0) disable_e1();
+            #if EXTRUDERS > 2
              if (g_uc_extruder_last_move[2] == 0) disable_e2();
+              #if EXTRUDERS > 3
                if (g_uc_extruder_last_move[3] == 0) disable_e3();
+              #endif
+            #endif
+          #endif
        break;
+        #if EXTRUDERS > 1
          case 1:
            enable_e1();
            g_uc_extruder_last_move[1] = BLOCK_BUFFER_SIZE*2;
-          
            if (g_uc_extruder_last_move[0] == 0) disable_e0();
+            #if EXTRUDERS > 2
              if (g_uc_extruder_last_move[2] == 0) disable_e2();
+              #if EXTRUDERS > 3
                if (g_uc_extruder_last_move[3] == 0) disable_e3();
+              #endif
+            #endif
          break;
+          #if EXTRUDERS > 2
            case 2:
              enable_e2();
              g_uc_extruder_last_move[2] = BLOCK_BUFFER_SIZE*2;
-          
              if (g_uc_extruder_last_move[0] == 0) disable_e0();
              if (g_uc_extruder_last_move[1] == 0) disable_e1();
+              #if EXTRUDERS > 3
                if (g_uc_extruder_last_move[3] == 0) disable_e3();
+              #endif
            break;
+            #if EXTRUDERS > 3
              case 3:
                enable_e3();
                g_uc_extruder_last_move[3] = BLOCK_BUFFER_SIZE*2;
-          
                if (g_uc_extruder_last_move[0] == 0) disable_e0();
                if (g_uc_extruder_last_move[1] == 0) disable_e1();
                if (g_uc_extruder_last_move[2] == 0) disable_e2();
              break;
+            #endif // EXTRUDERS > 3
+          #endif // EXTRUDERS > 2
+        #endif // EXTRUDERS > 1
      }
    }
-    else //enable all
-    {
+    else { // enable all
      enable_e0();
      enable_e1();
      enable_e2();
@ -729,67 +647,65 @@ block->steps_y = labs((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-positi
    }
  }

-  if (block->steps_e == 0)
-  {
-    if(feed_rate<mintravelfeedrate) feed_rate=mintravelfeedrate;
-  }
-  else
-  {
+  if (block->steps[E_AXIS]) {
    if (feed_rate < minimumfeedrate) feed_rate = minimumfeedrate;
  }
+  else if (feed_rate < mintravelfeedrate) feed_rate = mintravelfeedrate;

-/* 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.
+  /**
+   * 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.
   */ 
-  #ifndef COREXY
-    float delta_mm[4];
-    delta_mm[X_AXIS] = (target[X_AXIS]-position[X_AXIS])/axis_steps_per_unit[X_AXIS];
-    delta_mm[Y_AXIS] = (target[Y_AXIS]-position[Y_AXIS])/axis_steps_per_unit[Y_AXIS];
-  #else
+  #ifdef COREXY
    float delta_mm[6];
-    delta_mm[X_HEAD] = (target[X_AXIS]-position[X_AXIS])/axis_steps_per_unit[X_AXIS];
-    delta_mm[Y_HEAD] = (target[Y_AXIS]-position[Y_AXIS])/axis_steps_per_unit[Y_AXIS];
-    delta_mm[X_AXIS] = ((target[X_AXIS]-position[X_AXIS]) + (target[Y_AXIS]-position[Y_AXIS]))/axis_steps_per_unit[X_AXIS];
-    delta_mm[Y_AXIS] = ((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-position[Y_AXIS]))/axis_steps_per_unit[Y_AXIS];
+    delta_mm[X_HEAD] = dx / axis_steps_per_unit[A_AXIS];
+    delta_mm[Y_HEAD] = dy / axis_steps_per_unit[B_AXIS];
+    delta_mm[A_AXIS] = (dx + dy) / axis_steps_per_unit[A_AXIS];
+    delta_mm[B_AXIS] = (dx - dy) / axis_steps_per_unit[B_AXIS];
+  #else
+    float delta_mm[4];
+    delta_mm[X_AXIS] = dx / axis_steps_per_unit[X_AXIS];
+    delta_mm[Y_AXIS] = dy / axis_steps_per_unit[Y_AXIS];
  #endif
-  delta_mm[Z_AXIS] = (target[Z_AXIS]-position[Z_AXIS])/axis_steps_per_unit[Z_AXIS];
-  delta_mm[E_AXIS] = ((target[E_AXIS]-position[E_AXIS])/axis_steps_per_unit[E_AXIS])*volumetric_multiplier[active_extruder]*extrudemultiply/100.0;
-  if ( block->steps_x <=dropsegments && block->steps_y <=dropsegments && block->steps_z <=dropsegments )
-  {
+  delta_mm[Z_AXIS] = dz / axis_steps_per_unit[Z_AXIS];
+  delta_mm[E_AXIS] = (de / axis_steps_per_unit[E_AXIS]) * volumetric_multiplier[active_extruder] * extrudemultiply / 100.0;
+
+  if (block->steps[X_AXIS] <= dropsegments && block->steps[Y_AXIS] <= dropsegments && block->steps[Z_AXIS] <= dropsegments) {
    block->millimeters = fabs(delta_mm[E_AXIS]);
  } 
-  else
-  {
-    #ifndef COREXY
-      block->millimeters = sqrt(square(delta_mm[X_AXIS]) + square(delta_mm[Y_AXIS]) + square(delta_mm[Z_AXIS]));
+  else {
+    block->millimeters = sqrt(
+      #ifdef COREXY
+        square(delta_mm[X_HEAD]) + square(delta_mm[Y_HEAD])
      #else
-	  block->millimeters = sqrt(square(delta_mm[X_HEAD]) + square(delta_mm[Y_HEAD]) + square(delta_mm[Z_AXIS]));
+        square(delta_mm[X_AXIS]) + square(delta_mm[Y_AXIS])
      #endif
+      + square(delta_mm[Z_AXIS])
+    );
  }
  float inverse_millimeters = 1.0 / block->millimeters;  // Inverse millimeters to remove multiple divides 

  // Calculate speed in mm/second for each axis. No divide by zero due to previous checks.
  float inverse_second = feed_rate * inverse_millimeters;

-  int moves_queued=(block_buffer_head-block_buffer_tail + BLOCK_BUFFER_SIZE) & (BLOCK_BUFFER_SIZE - 1);
+  int moves_queued = movesplanned();

  // slow down when de buffer starts to empty, rather than wait at the corner for a buffer refill
+  bool mq = moves_queued > 1 && moves_queued < BLOCK_BUFFER_SIZE / 2;
  #ifdef OLD_SLOWDOWN
-  if(moves_queued < (BLOCK_BUFFER_SIZE * 0.5) && moves_queued > 1)
-    feed_rate = feed_rate*moves_queued / (BLOCK_BUFFER_SIZE * 0.5); 
+    if (mq) feed_rate *= 2.0 * moves_queued / BLOCK_BUFFER_SIZE;
  #endif

  #ifdef SLOWDOWN
    //  segment time im micro seconds
    unsigned long segment_time = lround(1000000.0/inverse_second);
-  if ((moves_queued > 1) && (moves_queued < (BLOCK_BUFFER_SIZE * 0.5)))
-  {
-    if (segment_time < minsegmenttime)
-    { // buffer is draining, add extra time.  The amount of time added increases if the buffer is still emptied more.
+    if (mq) {
+      if (segment_time < minsegmenttime) {
+        // buffer is draining, add extra time.  The amount of time added increases if the buffer is still emptied more.
        inverse_second = 1000000.0 / (segment_time + lround(2 * (minsegmenttime - segment_time) / moves_queued));
        #ifdef XY_FREQUENCY_LIMIT
          segment_time = lround(1000000.0 / inverse_second);
@ -799,135 +715,116 @@ Having the real displacement of the head, we can calculate the total movement le
  #endif
  //  END OF SLOW DOWN SECTION    

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

  #ifdef FILAMENT_SENSOR
    //FMM update ring buffer used for delay with filament measurements
  
+    if (extruder == FILAMENT_SENSOR_EXTRUDER_NUM && delay_index2 > -1) {  //only for extruder with filament sensor and if ring buffer is initialized

-    if((extruder==FILAMENT_SENSOR_EXTRUDER_NUM) && (delay_index2 > -1))  //only for extruder with filament sensor and if ring buffer is initialized
-  	  {
-    delay_dist = delay_dist + delta_mm[E_AXIS];  //increment counter with next move in e axis
+      const int MMD = MAX_MEASUREMENT_DELAY + 1, MMD10 = MMD * 10;

-    while (delay_dist >= (10*(MAX_MEASUREMENT_DELAY+1)))  //check if counter is over max buffer size in mm
-      	  delay_dist = delay_dist - 10*(MAX_MEASUREMENT_DELAY+1);  //loop around the buffer
-    while (delay_dist<0)
-    	  delay_dist = delay_dist + 10*(MAX_MEASUREMENT_DELAY+1); //loop around the buffer
+      delay_dist += delta_mm[E_AXIS];  // increment counter with next move in e axis
+      while (delay_dist >= MMD10) delay_dist -= MMD10; // loop around the buffer
+      while (delay_dist < 0) delay_dist += MMD10;

      delay_index1 = delay_dist / 10.0;  // calculate index
-    
-    //ensure the number is within range of the array after converting from floating point
-    if(delay_index1<0)
-    	delay_index1=0;
-    else if (delay_index1>MAX_MEASUREMENT_DELAY)
-    	delay_index1=MAX_MEASUREMENT_DELAY;
-    	
-    if(delay_index1 != delay_index2)  //moved index
-  	  {
-    	meas_sample=widthFil_to_size_ratio()-100;  //subtract off 100 to reduce magnitude - to store in a signed char
-  	  }
-    while( delay_index1 != delay_index2)
-  	  {
-  	  delay_index2 = delay_index2 + 1;
-  	if(delay_index2>MAX_MEASUREMENT_DELAY)
-  			  delay_index2=delay_index2-(MAX_MEASUREMENT_DELAY+1);  //loop around buffer when incrementing
-  	  if(delay_index2<0)
-  		delay_index2=0;
-  	  else if (delay_index2>MAX_MEASUREMENT_DELAY)
-  		delay_index2=MAX_MEASUREMENT_DELAY;  
-  	  
+      delay_index1 = constrain(delay_index1, 0, MAX_MEASUREMENT_DELAY); // (already constrained above)
+
+      if (delay_index1 != delay_index2) { // moved index
+        meas_sample = widthFil_to_size_ratio() - 100;  // Subtract 100 to reduce magnitude - to store in a signed char
+        while (delay_index1 != delay_index2) {
+          // Increment and loop around buffer
+          if (++delay_index2 >= MMD) delay_index2 -= MMD;
+          delay_index2 = constrain(delay_index2, 0, MAX_MEASUREMENT_DELAY);
          measurement_delay[delay_index2] = meas_sample;
        }
-    	
-    
+      }
    }
  #endif

-
  // Calculate and limit speed in mm/sec for each axis
-  float current_speed[4];
+  float current_speed[NUM_AXIS];
  float speed_factor = 1.0; //factor <=1 do decrease speed
-  for(int i=0; i < 4; i++)
-  {
+  for (int i = 0; i < NUM_AXIS; i++) {
    current_speed[i] = delta_mm[i] * inverse_second;
-    if(fabs(current_speed[i]) > max_feedrate[i])
-      speed_factor = min(speed_factor, max_feedrate[i] / fabs(current_speed[i]));
+    float cs = fabs(current_speed[i]), mf = max_feedrate[i];
+    if (cs > mf) speed_factor = min(speed_factor, mf / cs);
  }

  // Max segement time in us.
  #ifdef XY_FREQUENCY_LIMIT
    #define MAX_FREQ_TIME (1000000.0 / XY_FREQUENCY_LIMIT)
+
    // Check and limit the xy direction change frequency
    unsigned char direction_change = block->direction_bits ^ old_direction_bits;
    old_direction_bits = block->direction_bits;
    segment_time = lround((float)segment_time / speed_factor);
  
-  if((direction_change & BIT(X_AXIS)) == 0)
-  {
-    x_segment_time[0] += segment_time;
+    long xs0 = axis_segment_time[X_AXIS][0],
+         xs1 = axis_segment_time[X_AXIS][1],
+         xs2 = axis_segment_time[X_AXIS][2],
+         ys0 = axis_segment_time[Y_AXIS][0],
+         ys1 = axis_segment_time[Y_AXIS][1],
+         ys2 = axis_segment_time[Y_AXIS][2];
+
+    if ((direction_change & BIT(X_AXIS)) != 0) {
+      xs2 = axis_segment_time[X_AXIS][2] = xs1;
+      xs1 = axis_segment_time[X_AXIS][1] = xs0;
+      xs0 = 0;
    }
-  else
-  {
-    x_segment_time[2] = x_segment_time[1];
-    x_segment_time[1] = x_segment_time[0];
-    x_segment_time[0] = segment_time;
+    xs0 = axis_segment_time[X_AXIS][0] = xs0 + segment_time;
+
+    if ((direction_change & BIT(Y_AXIS)) != 0) {
+      ys2 = axis_segment_time[Y_AXIS][2] = axis_segment_time[Y_AXIS][1];
+      ys1 = axis_segment_time[Y_AXIS][1] = axis_segment_time[Y_AXIS][0];
+      ys0 = 0;
    }
-  if((direction_change & BIT(Y_AXIS)) == 0)
-  {
-    y_segment_time[0] += segment_time;
+    ys0 = axis_segment_time[Y_AXIS][0] = ys0 + segment_time;
+
+    long max_x_segment_time = max(xs0, max(xs1, xs2)),
+         max_y_segment_time = max(ys0, max(ys1, ys2)),
+         min_xy_segment_time = min(max_x_segment_time, max_y_segment_time);
+    if (min_xy_segment_time < MAX_FREQ_TIME) {
+      float low_sf = speed_factor * min_xy_segment_time / MAX_FREQ_TIME;
+      speed_factor = min(speed_factor, low_sf);
    }
-  else
-  {
-    y_segment_time[2] = y_segment_time[1];
-    y_segment_time[1] = y_segment_time[0];
-    y_segment_time[0] = segment_time;
-  }
-  long max_x_segment_time = max(x_segment_time[0], max(x_segment_time[1], x_segment_time[2]));
-  long max_y_segment_time = max(y_segment_time[0], max(y_segment_time[1], y_segment_time[2]));
-  long min_xy_segment_time =min(max_x_segment_time, max_y_segment_time);
-  if(min_xy_segment_time < MAX_FREQ_TIME)
-    speed_factor = min(speed_factor, speed_factor * (float)min_xy_segment_time / (float)MAX_FREQ_TIME);
  #endif // XY_FREQUENCY_LIMIT

  // Correct the speed  
-  if( speed_factor < 1.0)
-  {
-    for(unsigned char i=0; i < 4; i++)
-    {
-      current_speed[i] *= speed_factor;
-    }
+  if (speed_factor < 1.0) {
+    for (unsigned char i = 0; i < NUM_AXIS; 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.  
  float steps_per_mm = block->step_event_count / block->millimeters;
-  if(block->steps_x == 0 && block->steps_y == 0 && block->steps_z == 0)
-  {
+  long bsx = block->steps[X_AXIS], bsy = block->steps[Y_AXIS], bsz = block->steps[Z_AXIS], bse = block->steps[E_AXIS];
+  if (bsx == 0 && bsy == 0 && bsz == 0) {
    block->acceleration_st = ceil(retract_acceleration * steps_per_mm); // convert to: acceleration steps/sec^2
  }
-  else if(block->steps_e == 0)
-  {
+  else if (bse == 0) {
    block->acceleration_st = ceil(travel_acceleration * steps_per_mm); // convert to: acceleration steps/sec^2
  }
-  else
-  {
+  else {
    block->acceleration_st = ceil(acceleration * steps_per_mm); // convert to: acceleration steps/sec^2
  }
  // Limit acceleration per axis
-  if(((float)block->acceleration_st * (float)block->steps_x / (float)block->step_event_count) > axis_steps_per_sqr_second[X_AXIS])
-    block->acceleration_st = axis_steps_per_sqr_second[X_AXIS];
-  if(((float)block->acceleration_st * (float)block->steps_y / (float)block->step_event_count) > axis_steps_per_sqr_second[Y_AXIS])
-    block->acceleration_st = axis_steps_per_sqr_second[Y_AXIS];
-  if(((float)block->acceleration_st * (float)block->steps_e / (float)block->step_event_count) > axis_steps_per_sqr_second[E_AXIS])
-    block->acceleration_st = axis_steps_per_sqr_second[E_AXIS];
-  if(((float)block->acceleration_st * (float)block->steps_z / (float)block->step_event_count ) > axis_steps_per_sqr_second[Z_AXIS])
-    block->acceleration_st = axis_steps_per_sqr_second[Z_AXIS];
- 
-  block->acceleration = block->acceleration_st / steps_per_mm;
-  block->acceleration_rate = (long)((float)block->acceleration_st * (16777216.0 / (F_CPU / 8.0)));
+  unsigned long acc_st = block->acceleration_st,
+                xsteps = axis_steps_per_sqr_second[X_AXIS],
+                ysteps = axis_steps_per_sqr_second[Y_AXIS],
+                zsteps = axis_steps_per_sqr_second[Z_AXIS],
+                esteps = axis_steps_per_sqr_second[E_AXIS];
+  if ((float)acc_st * bsx / block->step_event_count > xsteps) acc_st = xsteps;
+  if ((float)acc_st * bsy / block->step_event_count > ysteps) acc_st = ysteps;
+  if ((float)acc_st * bsz / block->step_event_count > zsteps) acc_st = zsteps;
+  if ((float)acc_st * bse / block->step_event_count > esteps) acc_st = esteps;
+ 
+  block->acceleration_st = acc_st;
+  block->acceleration = acc_st / steps_per_mm;
+  block->acceleration_rate = (long)(acc_st * 16777216.0 / (F_CPU / 8.0));

  #if 0  // Use old jerk for now
    // Compute path unit vector
@ -969,30 +866,31 @@ Having the real displacement of the head, we can calculate the total movement le
      }
    }
  #endif
+
  // Start with a safe speed
  float vmax_junction = max_xy_jerk / 2;
  float vmax_junction_factor = 1.0; 
-  if(fabs(current_speed[Z_AXIS]) > max_z_jerk/2) 
-    vmax_junction = min(vmax_junction, max_z_jerk/2);
-  if(fabs(current_speed[E_AXIS]) > max_e_jerk/2) 
-    vmax_junction = min(vmax_junction, max_e_jerk/2);
+  float mz2 = max_z_jerk / 2, me2 = max_e_jerk / 2;
+  float csz = current_speed[Z_AXIS], cse = current_speed[E_AXIS];
+  if (fabs(csz) > mz2) vmax_junction = min(vmax_junction, mz2);
+  if (fabs(cse) > me2) vmax_junction = min(vmax_junction, me2);
  vmax_junction = min(vmax_junction, block->nominal_speed);
  float safe_speed = vmax_junction;

  if ((moves_queued > 1) && (previous_nominal_speed > 0.0001)) {
-    float jerk = sqrt(pow((current_speed[X_AXIS]-previous_speed[X_AXIS]), 2)+pow((current_speed[Y_AXIS]-previous_speed[Y_AXIS]), 2));
+    float dx = current_speed[X_AXIS] - previous_speed[X_AXIS],
+          dy = current_speed[Y_AXIS] - previous_speed[Y_AXIS],
+          dz = fabs(csz - previous_speed[Z_AXIS]),
+          de = fabs(cse - previous_speed[E_AXIS]),
+          jerk = sqrt(dx * dx + dy * dy);
+
    //    if ((fabs(previous_speed[X_AXIS]) > 0.0001) || (fabs(previous_speed[Y_AXIS]) > 0.0001)) {
    vmax_junction = block->nominal_speed;
    //    }
-    if (jerk > max_xy_jerk) {
-      vmax_junction_factor = (max_xy_jerk/jerk);
-    } 
-    if(fabs(current_speed[Z_AXIS] - previous_speed[Z_AXIS]) > max_z_jerk) {
-      vmax_junction_factor= min(vmax_junction_factor, (max_z_jerk/fabs(current_speed[Z_AXIS] - previous_speed[Z_AXIS])));
-    } 
-    if(fabs(current_speed[E_AXIS] - previous_speed[E_AXIS]) > max_e_jerk) {
-      vmax_junction_factor = min(vmax_junction_factor, (max_e_jerk/fabs(current_speed[E_AXIS] - previous_speed[E_AXIS])));
-    } 
+    if (jerk > max_xy_jerk) vmax_junction_factor = max_xy_jerk / jerk;
+    if (dz > max_z_jerk) vmax_junction_factor = min(vmax_junction_factor, max_z_jerk / dz);
+    if (de > max_e_jerk) vmax_junction_factor = min(vmax_junction_factor, max_e_jerk / de);
+
    vmax_junction = min(previous_nominal_speed, vmax_junction * vmax_junction_factor); // Limit speed to max previous speed
  }
  block->max_entry_speed = vmax_junction;
@ -1009,36 +907,24 @@ Having the real displacement of the head, we can calculate the total movement le
  // 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.
-  if (block->nominal_speed <= v_allowable) { 
-    block->nominal_length_flag = true; 
-  }
-  else { 
-    block->nominal_length_flag = false; 
-  }
+  block->nominal_length_flag = (block->nominal_speed <= v_allowable); 
  block->recalculate_flag = true; // Always calculate trapezoid for new block

  // Update previous path unit_vector and nominal speed
-  memcpy(previous_speed, current_speed, sizeof(previous_speed)); // previous_speed[] = current_speed[]
+  for (int i = 0; i < NUM_AXIS; i++) previous_speed[i] = current_speed[i];
  previous_nominal_speed = block->nominal_speed;

-
  #ifdef ADVANCE
    // Calculate advance rate
-  if((block->steps_e == 0) || (block->steps_x == 0 && block->steps_y == 0 && block->steps_z == 0)) {
+    if (!bse || (!bsx && !bsy && !bsz)) {
      block->advance_rate = 0;
      block->advance = 0;
    }
    else {
      long acc_dist = estimate_acceleration_distance(0, block->nominal_rate, block->acceleration_st);
-    float advance = (STEPS_PER_CUBIC_MM_E * EXTRUDER_ADVANCE_K) * 
-      (current_speed[E_AXIS] * current_speed[E_AXIS] * EXTRUSION_AREA * EXTRUSION_AREA)*256;
+      float advance = (STEPS_PER_CUBIC_MM_E * EXTRUDER_ADVANCE_K) * (cse * cse * EXTRUSION_AREA * EXTRUSION_AREA) * 256;
      block->advance = advance;
-    if(acc_dist == 0) {
-      block->advance_rate = 0;
-    } 
-    else {
-      block->advance_rate = advance / (float)acc_dist;
-    }
+      block->advance_rate = acc_dist ? advance / (float)acc_dist : 0;
    }
    /*
      SERIAL_ECHO_START;
@ -1049,21 +935,23 @@ Having the real displacement of the head, we can calculate the total movement le
     */
  #endif // ADVANCE

-  calculate_trapezoid_for_block(block, block->entry_speed/block->nominal_speed,
-  safe_speed/block->nominal_speed);
+  calculate_trapezoid_for_block(block, block->entry_speed / block->nominal_speed, safe_speed / block->nominal_speed);

  // Move buffer head
  block_buffer_head = next_buffer_head;

  // Update position
-  memcpy(position, target, sizeof(target)); // position[] = target[]
+  for (int i = 0; i < NUM_AXIS; i++) position[i] = target[i];

  planner_recalculate();

  st_wake_up();
-}

-#if defined(ENABLE_AUTO_BED_LEVELING) && not defined(DELTA)
+} // plan_buffer_line()
+
+#ifdef ENABLE_AUTO_BED_LEVELING
+
+  #ifndef DELTA
    vector_3 plan_get_position() {
      vector_3 position = vector_3(st_get_position_mm(X_AXIS), st_get_position_mm(Y_AXIS), st_get_position_mm(Z_AXIS));

@ -1076,52 +964,38 @@ vector_3 plan_get_position() {

      return position;
    }
-#endif // ENABLE_AUTO_BED_LEVELING
+  #endif //!DELTA

-#ifdef ENABLE_AUTO_BED_LEVELING
  void plan_set_position(float x, float y, float z, const float &e)
-{
-  apply_rotation_xyz(plan_bed_level_matrix, x, y, z);
 #else
  void plan_set_position(const float &x, const float &y, const float &z, const float &e)
-{
 #endif // ENABLE_AUTO_BED_LEVELING
+  {
+    #ifdef ENABLE_AUTO_BED_LEVELING
+      apply_rotation_xyz(plan_bed_level_matrix, x, y, z);
+    #endif

-  position[X_AXIS] = lround(x*axis_steps_per_unit[X_AXIS]);
-  position[Y_AXIS] = lround(y*axis_steps_per_unit[Y_AXIS]);
-  position[Z_AXIS] = lround(z*axis_steps_per_unit[Z_AXIS]);     
-  position[E_AXIS] = lround(e*axis_steps_per_unit[E_AXIS]);  
-  st_set_position(position[X_AXIS], position[Y_AXIS], position[Z_AXIS], position[E_AXIS]);
+    float nx = position[X_AXIS] = lround(x * axis_steps_per_unit[X_AXIS]);
+    float ny = position[Y_AXIS] = lround(y * axis_steps_per_unit[Y_AXIS]);
+    float nz = position[Z_AXIS] = lround(z * axis_steps_per_unit[Z_AXIS]);
+    float ne = position[E_AXIS] = lround(e * axis_steps_per_unit[E_AXIS]);
+    st_set_position(nx, ny, nz, ne);
    previous_nominal_speed = 0.0; // Resets planner junction speeds. Assumes start from rest.
-  previous_speed[0] = 0.0;
-  previous_speed[1] = 0.0;
-  previous_speed[2] = 0.0;
-  previous_speed[3] = 0.0;
+
+    for (int i=0; i<NUM_AXIS; i++) previous_speed[i] = 0.0;
  }

-void plan_set_e_position(const float &e)
-{
+void plan_set_e_position(const float &e) {
  position[E_AXIS] = lround(e * axis_steps_per_unit[E_AXIS]);  
  st_set_e_position(position[E_AXIS]);
 }

-uint8_t movesplanned()
-{
-  return (block_buffer_head-block_buffer_tail + BLOCK_BUFFER_SIZE) & (BLOCK_BUFFER_SIZE - 1);
-}
-
 #ifdef PREVENT_DANGEROUS_EXTRUDE
-void set_extrude_min_temp(float temp)
-{
-  extrude_min_temp=temp;
-}
+  void set_extrude_min_temp(float temp) { extrude_min_temp = temp; }
 #endif

 // Calculate the steps/s^2 acceleration rates, based on the mm/s^s
-void reset_acceleration_rates()
-{
-	for(int8_t i=0; i < NUM_AXIS; i++)
-        {
+void reset_acceleration_rates() {
+  for (int i = 0; i < NUM_AXIS; i++)
    axis_steps_per_sqr_second[i] = max_acceleration_units_per_sq_second[i] * axis_steps_per_unit[i];
 }
-}
--- a/Marlin/planner.h
+++ b/Marlin/planner.h
@ -21,20 +21,16 @@
 // This module is to be considered a sub-module of stepper.c. Please don't include 
 // this file from any other module.

-#ifndef planner_h
-#define planner_h
+#ifndef PLANNER_H
+#define PLANNER_H

 #include "Marlin.h"

-#ifdef ENABLE_AUTO_BED_LEVELING
-#include "vector_3.h"
-#endif // ENABLE_AUTO_BED_LEVELING
-
 // This struct is used when buffering the setup for each linear movement "nominal" values are as specified in 
 // the source g-code and may never actually be reached if acceleration management is active.
 typedef struct {
  // Fields used by the bresenham algorithm for tracing the line
-  long steps_x, steps_y, steps_z, steps_e;  // Step count along each axis
+  long steps[NUM_AXIS];                     // Step count along each axis
  unsigned long step_event_count;           // The number of step events required to complete this block
  long accelerate_until;                    // The index of the step event on which to stop acceleration
  long decelerate_after;                    // The index of the step event on which to start decelerating
@ -71,42 +67,38 @@ typedef struct {
  volatile char busy;
 } block_t;

-#ifdef ENABLE_AUTO_BED_LEVELING
-// this holds the required transform to compensate for bed level
-extern matrix_3x3 plan_bed_level_matrix;
-#endif // #ifdef ENABLE_AUTO_BED_LEVELING
+#define BLOCK_MOD(n) ((n)&(BLOCK_BUFFER_SIZE-1))

 // Initialize the motion plan subsystem      
 void plan_init();

-// Add a new linear movement to the buffer. x, y and z is the signed, absolute target position in 
-// millimaters. Feed rate specifies the speed of the motion.
+void check_axes_activity();
+
+// Get the number of buffered moves
+extern volatile unsigned char block_buffer_head;
+extern volatile unsigned char block_buffer_tail;
+FORCE_INLINE uint8_t movesplanned() { return BLOCK_MOD(block_buffer_head - block_buffer_tail + BLOCK_BUFFER_SIZE); }

 #ifdef ENABLE_AUTO_BED_LEVELING
+  #include "vector_3.h"
+  // this holds the required transform to compensate for bed level
+  extern matrix_3x3 plan_bed_level_matrix;
+  // Add a new linear movement to the buffer. x, y and z is the signed, absolute target position in 
+  // millimaters. Feed rate specifies the speed of the motion.
  void plan_buffer_line(float x, float y, float z, const float &e, float feed_rate, const uint8_t &extruder);
-
+  // Set position. Used for G92 instructions.
+  void plan_set_position(float x, float y, float z, const float &e);
  #ifndef DELTA
    // Get the position applying the bed level matrix if enabled
    vector_3 plan_get_position();
  #endif
-#else
+#else //!ENABLE_AUTO_BED_LEVELING
  void plan_buffer_line(const float &x, const float &y, const float &z, const float &e, float feed_rate, const uint8_t &extruder);
-#endif // ENABLE_AUTO_BED_LEVELING
-
-// Set position. Used for G92 instructions.
-#ifdef ENABLE_AUTO_BED_LEVELING
-void plan_set_position(float x, float y, float z, const float &e);
-#else
  void plan_set_position(const float &x, const float &y, const float &z, const float &e);
-#endif // ENABLE_AUTO_BED_LEVELING
+#endif //!ENABLE_AUTO_BED_LEVELING

 void plan_set_e_position(const float &e);

-
-
-void check_axes_activity();
-uint8_t movesplanned(); //return the nr of buffered moves
-
 extern unsigned long minsegmenttime;
 extern float max_feedrate[NUM_AXIS]; // set the max speeds
 extern float axis_steps_per_unit[NUM_AXIS];
@ -128,38 +120,35 @@ extern unsigned long axis_steps_per_sqr_second[NUM_AXIS];
  extern float autotemp_factor;
 #endif

-    
-
-
-extern block_t block_buffer[BLOCK_BUFFER_SIZE];            // A ring buffer for motion instfructions
+extern block_t block_buffer[BLOCK_BUFFER_SIZE];            // A ring buffer for motion instructions
 extern volatile unsigned char block_buffer_head;           // Index of the next block to be pushed
 extern volatile unsigned char block_buffer_tail; 
-// Called when the current block is no longer needed. Discards the block and makes the memory
-// availible for new blocks.    
-FORCE_INLINE void plan_discard_current_block()  
-{
-  if (block_buffer_head != block_buffer_tail) {
-    block_buffer_tail = (block_buffer_tail + 1) & (BLOCK_BUFFER_SIZE - 1);  
-  }
+
+// Returns true if the buffer has a queued block, false otherwise
+FORCE_INLINE bool blocks_queued() { return (block_buffer_head != block_buffer_tail); }
+
+// Called when the current block is no longer needed. Discards
+// the block and makes the memory available for new blocks.
+FORCE_INLINE void plan_discard_current_block() {
+  if (blocks_queued())
+    block_buffer_tail = BLOCK_MOD(block_buffer_tail + 1);
 }

 // Gets the current block. Returns NULL if buffer empty
-FORCE_INLINE block_t *plan_get_current_block() 
-{
-  if (block_buffer_head == block_buffer_tail) { 
-    return(NULL); 
-  }
+FORCE_INLINE block_t *plan_get_current_block() {
+  if (blocks_queued()) {
    block_t *block = &block_buffer[block_buffer_tail];
    block->busy = true;
-  return(block);
+    return block;
+  }
+  else
+    return NULL;
 }
-
-// Returns true if the buffer has a queued block, false otherwise
-FORCE_INLINE bool blocks_queued() { return (block_buffer_head != block_buffer_tail); }

 #ifdef PREVENT_DANGEROUS_EXTRUDE
  void set_extrude_min_temp(float temp);
 #endif

 void reset_acceleration_rates();
-#endif
+
+#endif //PLANNER_H
--- a/Marlin/stepper.cpp
+++ b/Marlin/stepper.cpp
@ -370,7 +370,7 @@ ISR(TIMER1_COMPA_vect) {
      step_events_completed = 0;

      #ifdef Z_LATE_ENABLE
-        if (current_block->steps_z > 0) {
+        if (current_block->steps[Z_AXIS] > 0) {
          enable_z();
          OCR1A = 2000; //1ms wait
          return;
@ -411,7 +411,7 @@ ISR(TIMER1_COMPA_vect) {

    #define UPDATE_ENDSTOP(axis,AXIS,minmax,MINMAX) \
      bool axis ##_## minmax ##_endstop = (READ(AXIS ##_## MINMAX ##_PIN) != AXIS ##_## MINMAX ##_ENDSTOP_INVERTING); \
-      if (axis ##_## minmax ##_endstop && old_## axis ##_## minmax ##_endstop && (current_block->steps_## axis > 0)) { \
+      if (axis ##_## minmax ##_endstop && old_## axis ##_## minmax ##_endstop && (current_block->steps[AXIS ##_AXIS] > 0)) { \
        endstops_trigsteps[AXIS ##_AXIS] = count_position[AXIS ##_AXIS]; \
        endstop_## axis ##_hit = true; \
        step_events_completed = current_block->step_event_count; \
@ -420,13 +420,13 @@ ISR(TIMER1_COMPA_vect) {

    // Check X and Y endstops
    if (check_endstops) {
-      #ifndef COREXY
-        if (TEST(out_bits, X_AXIS))   // stepping along -X axis (regular cartesians bot)
-      #else
+      #ifdef COREXY
        // Head direction in -X axis for CoreXY bots.
        // If DeltaX == -DeltaY, the movement is only in Y axis
-        if (current_block->steps_x != current_block->steps_y || (TEST(out_bits, X_AXIS) == TEST(out_bits, Y_AXIS)))      
+        if (current_block->steps[A_AXIS] != current_block->steps[B_AXIS] || (TEST(out_bits, A_AXIS) == TEST(out_bits, B_AXIS)))
          if (TEST(out_bits, X_HEAD))
+      #else
+          if (TEST(out_bits, X_AXIS))   // stepping along -X axis (regular cartesians bot)
      #endif
          { // -direction
            #ifdef DUAL_X_CARRIAGE
@ -450,13 +450,13 @@ ISR(TIMER1_COMPA_vect) {
                #endif
              }
          }
-      #ifndef COREXY
-        if (TEST(out_bits, Y_AXIS))   // -direction
-      #else
+      #ifdef COREXY
        // Head direction in -Y axis for CoreXY bots.
        // If DeltaX == DeltaY, the movement is only in X axis
-        if (current_block->steps_x != current_block->steps_y || (TEST(out_bits, X_AXIS) != TEST(out_bits, Y_AXIS)))
+        if (current_block->steps[A_AXIS] != current_block->steps[B_AXIS] || (TEST(out_bits, A_AXIS) != TEST(out_bits, B_AXIS)))
          if (TEST(out_bits, Y_HEAD))
+      #else
+          if (TEST(out_bits, Y_AXIS))   // -direction
      #endif
          { // -direction
            #if defined(Y_MIN_PIN) && Y_MIN_PIN >= 0
@ -515,7 +515,7 @@ ISR(TIMER1_COMPA_vect) {
      #endif

      #ifdef ADVANCE
-        counter_e += current_block->steps_e;
+        counter_e += current_block->steps[E_AXIS];
        if (counter_e > 0) {
          counter_e -= current_block->step_event_count;
          e_steps[current_block->active_extruder] += TEST(out_bits, E_AXIS) ? -1 : 1;
@ -529,15 +529,14 @@ ISR(TIMER1_COMPA_vect) {
         * instead of doing each in turn. The extra tests add enough
         * lag to allow it work with without needing NOPs
         */
-        counter_x += current_block->steps_x;
-        if (counter_x > 0) X_STEP_WRITE(HIGH);
-        counter_y += current_block->steps_y;
-        if (counter_y > 0) Y_STEP_WRITE(HIGH);
-        counter_z += current_block->steps_z;
-        if (counter_z > 0) Z_STEP_WRITE(HIGH);
+        #define STEP_ADD(axis, AXIS) \
+         counter_## axis += current_block->steps[AXIS ##_AXIS]; \
+         if (counter_## axis > 0) { AXIS ##_STEP_WRITE(HIGH); }
+        STEP_ADD(x,X);
+        STEP_ADD(y,Y);
+        STEP_ADD(z,Z);
        #ifndef ADVANCE
-          counter_e += current_block->steps_e;
-          if (counter_e > 0) E_STEP_WRITE(HIGH);
+          STEP_ADD(e,E);
        #endif

        #define STEP_IF_COUNTER(axis, AXIS) \
@ -557,7 +556,7 @@ ISR(TIMER1_COMPA_vect) {
      #else // !CONFIG_STEPPERS_TOSHIBA

        #define APPLY_MOVEMENT(axis, AXIS) \
-          counter_## axis += current_block->steps_## axis; \
+          counter_## axis += current_block->steps[AXIS ##_AXIS]; \
          if (counter_## axis > 0) { \
            AXIS ##_APPLY_STEP(!INVERT_## AXIS ##_STEP_PIN,0); \
            counter_## axis -= current_block->step_event_count; \