Spend 48b PROGMEM to save 16b SRAM

...by moving `homing_feedrate_mm_s` to PROGMEM.

Marlin/Marlin_main.cpp

@@ -389,7 +389,7 @@ static const char *injected_commands_P = NULL;
  * Feed rates are often configured with mm/m
  * but the planner and stepper like mm/s units.
  */
-float constexpr homing_feedrate_mm_s[] = {
+static const float homing_feedrate_mm_s[] PROGMEM = {
   #if ENABLED(DELTA)
     MMM_TO_MMS(HOMING_FEEDRATE_Z), MMM_TO_MMS(HOMING_FEEDRATE_Z),
   #else
@@ -397,6 +397,8 @@ float constexpr homing_feedrate_mm_s[] = {
   #endif
   MMM_TO_MMS(HOMING_FEEDRATE_Z), 0
 };
+FORCE_INLINE float homing_feedrate(const AxisEnum a) { return pgm_read_float(&homing_feedrate_mm_s[a]); }
+
 float feedrate_mm_s = MMM_TO_MMS(1500.0);
 static float saved_feedrate_mm_s;
 int feedrate_percentage = 100, saved_feedrate_percentage,
@@ -1504,7 +1506,7 @@ inline float get_homing_bump_feedrate(const AxisEnum axis) {
     SERIAL_ECHO_START;
     SERIAL_ECHOLNPGM("Warning: Homing Bump Divisor < 1");
   }
-  return homing_feedrate_mm_s[axis] / hbd;
+  return homing_feedrate(axis) / hbd;
 }
 
 /**
@@ -1631,7 +1633,7 @@ void do_blocking_move_to(const float &x, const float &y, const float &z, const f
     // If Z needs to raise, do it before moving XY
     if (destination[Z_AXIS] < z) {
       destination[Z_AXIS] = z;
-      prepare_uninterpolated_move_to_destination(fr_mm_s ? fr_mm_s : homing_feedrate_mm_s[Z_AXIS]);
+      prepare_uninterpolated_move_to_destination(fr_mm_s ? fr_mm_s : homing_feedrate(Z_AXIS));
     }
 
     destination[X_AXIS] = x;
@@ -1641,14 +1643,14 @@ void do_blocking_move_to(const float &x, const float &y, const float &z, const f
     // If Z needs to lower, do it after moving XY
     if (destination[Z_AXIS] > z) {
       destination[Z_AXIS] = z;
-      prepare_uninterpolated_move_to_destination(fr_mm_s ? fr_mm_s : homing_feedrate_mm_s[Z_AXIS]);
+      prepare_uninterpolated_move_to_destination(fr_mm_s ? fr_mm_s : homing_feedrate(Z_AXIS));
     }
 
   #else
 
     // If Z needs to raise, do it before moving XY
     if (current_position[Z_AXIS] < z) {
-      feedrate_mm_s = fr_mm_s ? fr_mm_s : homing_feedrate_mm_s[Z_AXIS];
+      feedrate_mm_s = fr_mm_s ? fr_mm_s : homing_feedrate(Z_AXIS);
       current_position[Z_AXIS] = z;
       line_to_current_position();
     }
@@ -1660,7 +1662,7 @@ void do_blocking_move_to(const float &x, const float &y, const float &z, const f
 
     // If Z needs to lower, do it after moving XY
     if (current_position[Z_AXIS] > z) {
-      feedrate_mm_s = fr_mm_s ? fr_mm_s : homing_feedrate_mm_s[Z_AXIS];
+      feedrate_mm_s = fr_mm_s ? fr_mm_s : homing_feedrate(Z_AXIS);
       current_position[Z_AXIS] = z;
       line_to_current_position();
     }
@@ -2778,11 +2780,11 @@ static void do_homing_move(const AxisEnum axis, const float distance, const floa
     SYNC_PLAN_POSITION_KINEMATIC();
     current_position[axis] = distance;
     inverse_kinematics(current_position);
-    planner.buffer_line(delta[A_AXIS], delta[B_AXIS], delta[C_AXIS], current_position[E_AXIS], fr_mm_s ? fr_mm_s : homing_feedrate_mm_s[axis], active_extruder);
+    planner.buffer_line(delta[A_AXIS], delta[B_AXIS], delta[C_AXIS], current_position[E_AXIS], fr_mm_s ? fr_mm_s : homing_feedrate(axis), active_extruder);
   #else
     sync_plan_position();
     current_position[axis] = distance;
-    planner.buffer_line(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS], fr_mm_s ? fr_mm_s : homing_feedrate_mm_s[axis], active_extruder);
+    planner.buffer_line(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS], fr_mm_s ? fr_mm_s : homing_feedrate(axis), active_extruder);
   #endif
 
   stepper.synchronize();
@@ -3397,7 +3399,7 @@ inline void gcode_G4() {
     const float mlx = max_length(X_AXIS),
                 mly = max_length(Y_AXIS),
                 mlratio = mlx > mly ? mly / mlx : mlx / mly,
-                fr_mm_s = min(homing_feedrate_mm_s[X_AXIS], homing_feedrate_mm_s[Y_AXIS]) * sqrt(sq(mlratio) + 1.0);
+                fr_mm_s = min(homing_feedrate(X_AXIS), homing_feedrate(Y_AXIS)) * sqrt(sq(mlratio) + 1.0);
 
     do_blocking_move_to_xy(1.5 * mlx * x_axis_home_dir, 1.5 * mly * home_dir(Y_AXIS), fr_mm_s);
     endstops.hit_on_purpose(); // clear endstop hit flags
@@ -3540,7 +3542,7 @@ inline void gcode_G4() {
 
     // Move all carriages together linearly until an endstop is hit.
     current_position[X_AXIS] = current_position[Y_AXIS] = current_position[Z_AXIS] = (Z_MAX_LENGTH + 10);
-    feedrate_mm_s = homing_feedrate_mm_s[X_AXIS];
+    feedrate_mm_s = homing_feedrate(X_AXIS);
     line_to_current_position();
     stepper.synchronize();
     endstops.hit_on_purpose(); // clear endstop hit flags
@@ -3853,7 +3855,7 @@ void home_all_axes() { gcode_G28(true); }
     const float old_feedrate_mm_s = feedrate_mm_s;
 
     #if MANUAL_PROBE_HEIGHT > 0
-      feedrate_mm_s = homing_feedrate_mm_s[Z_AXIS];
+      feedrate_mm_s = homing_feedrate(Z_AXIS);
       current_position[Z_AXIS] = LOGICAL_Z_POSITION(Z_MIN_POS) + MANUAL_PROBE_HEIGHT;
       line_to_current_position();
     #endif
@@ -3864,7 +3866,7 @@ void home_all_axes() { gcode_G28(true); }
     line_to_current_position();
 
     #if MANUAL_PROBE_HEIGHT > 0
-      feedrate_mm_s = homing_feedrate_mm_s[Z_AXIS];
+      feedrate_mm_s = homing_feedrate(Z_AXIS);
       current_position[Z_AXIS] = LOGICAL_Z_POSITION(Z_MIN_POS); // just slightly over the bed
       line_to_current_position();
     #endif
@@ -3900,7 +3902,7 @@ void home_all_axes() { gcode_G28(true); }
     #if ENABLED(MESH_G28_REST_ORIGIN)
       current_position[Z_AXIS] = LOGICAL_Z_POSITION(Z_MIN_POS);
       set_destination_to_current();
-      line_to_destination(homing_feedrate_mm_s[Z_AXIS]);
+      line_to_destination(homing_feedrate(Z_AXIS));
       stepper.synchronize();
     #endif
   }
@@ -5502,7 +5504,7 @@ void home_all_axes() { gcode_G28(true); }
     // If any axis has enough movement, do the move
     LOOP_XYZ(i)
       if (fabs(destination[i] - current_position[i]) >= G38_MINIMUM_MOVE) {
-        if (!parser.seen('F')) feedrate_mm_s = homing_feedrate_mm_s[i];
+        if (!parser.seen('F')) feedrate_mm_s = homing_feedrate(i);
         // If G38.2 fails throw an error
         if (!G38_run_probe() && is_38_2) {
           SERIAL_ERROR_START;