Patches for core motion tests

Marlin/src/core/enum.h

 /**
  * Axis indices as enumerated constants
  *
- * Special axis:
- *  - A_AXIS and B_AXIS are used by COREXY printers
- *  - 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
+ *  - X_AXIS, Y_AXIS, and Z_AXIS should be used for axes in Cartesian space
+ *  - A_AXIS, B_AXIS, and C_AXIS should be used for Steppers, corresponding to XYZ on Cartesians
+ *  - X_HEAD, Y_HEAD, and Z_HEAD should be used for Steppers on Core kinematics
  */
 enum AxisEnum : unsigned char {
   X_AXIS    = 0,

Marlin/src/core/macros.h

 #define TEST(n,b) !!((n)&_BV(b))
 #define SBI(n,b) (n |= _BV(b))
 #define CBI(n,b) (n &= ~_BV(b))
-#define SET_BIT(N,B,TF) do{ if (TF) SBI(N,B); else CBI(N,B); }while(0)
+#define SET_BIT_TO(N,B,TF) do{ if (TF) SBI(N,B); else CBI(N,B); }while(0)
 
 #define _BV32(b) (1UL << (b))
 #define TEST32(n,b) !!((n)&_BV32(b))

Marlin/src/module/endstops.cpp

 // Check endstops - Could be called from ISR!
 void Endstops::update() {
 
-  #define SET_BIT(N,B,TF) do{ if (TF) SBI(N,B); else CBI(N,B); }while(0)
+  #define SET_BIT_TO(N,B,TF) do{ if (TF) SBI(N,B); else CBI(N,B); }while(0)
   // UPDATE_ENDSTOP_BIT: set the current endstop bits for an endstop to its status
-  #define UPDATE_ENDSTOP_BIT(AXIS, MINMAX) SET_BIT(live_state, _ENDSTOP(AXIS, MINMAX), (READ(_ENDSTOP_PIN(AXIS, MINMAX)) != _ENDSTOP_INVERTING(AXIS, MINMAX)))
+  #define UPDATE_ENDSTOP_BIT(AXIS, MINMAX) SET_BIT_TO(live_state, _ENDSTOP(AXIS, MINMAX), (READ(_ENDSTOP_PIN(AXIS, MINMAX)) != _ENDSTOP_INVERTING(AXIS, MINMAX)))
   // COPY_BIT: copy the value of SRC_BIT to DST_BIT in DST
-  #define COPY_BIT(DST, SRC_BIT, DST_BIT) SET_BIT(DST, DST_BIT, TEST(DST, SRC_BIT))
+  #define COPY_BIT(DST, SRC_BIT, DST_BIT) SET_BIT_TO(DST, DST_BIT, TEST(DST, SRC_BIT))
 
   #if ENABLED(G38_PROBE_TARGET) && PIN_EXISTS(Z_MIN_PROBE) && !(CORE_IS_XY || CORE_IS_XZ)
     // If G38 command is active check Z_MIN_PROBE for ALL movement
     // If G38 command is active check Z_MIN_PROBE for ALL movement
     if (G38_move) {
       if (TEST_ENDSTOP(_ENDSTOP(Z, MIN_PROBE))) {
-        if      (stepper.axis_is_moving(_AXIS(X))) { _ENDSTOP_HIT(X, MIN); planner.endstop_triggered(_AXIS(X)); }
-        else if (stepper.axis_is_moving(_AXIS(Y))) { _ENDSTOP_HIT(Y, MIN); planner.endstop_triggered(_AXIS(Y)); }
-        else if (stepper.axis_is_moving(_AXIS(Z))) { _ENDSTOP_HIT(Z, MIN); planner.endstop_triggered(_AXIS(Z)); }
+        if      (stepper.axis_is_moving(X_AXIS)) { _ENDSTOP_HIT(X, MIN); planner.endstop_triggered(X_AXIS); }
+        else if (stepper.axis_is_moving(Y_AXIS)) { _ENDSTOP_HIT(Y, MIN); planner.endstop_triggered(Y_AXIS); }
+        else if (stepper.axis_is_moving(Z_AXIS)) { _ENDSTOP_HIT(Z, MIN); planner.endstop_triggered(Z_AXIS); }
         G38_endstop_hit = true;
       }
     }

Marlin/src/module/stepper.cpp

         #endif
         #define X_MOVE_TEST ( S_(1) != S_(2) || (S_(1) > 0 && D_(1) X_CMP D_(2)) )
       #else
-        #define X_MOVE_TEST !!current_block->steps[X_AXIS]
+        #define X_MOVE_TEST !!current_block->steps[A_AXIS]
       #endif
 
       #if CORE_IS_XY || CORE_IS_YZ
         #endif
         #define Y_MOVE_TEST ( S_(1) != S_(2) || (S_(1) > 0 && D_(1) Y_CMP D_(2)) )
       #else
-        #define Y_MOVE_TEST !!current_block->steps[Y_AXIS]
+        #define Y_MOVE_TEST !!current_block->steps[B_AXIS]
       #endif
 
       #if CORE_IS_XZ || CORE_IS_YZ
         #endif
         #define Z_MOVE_TEST ( S_(1) != S_(2) || (S_(1) > 0 && D_(1) Z_CMP D_(2)) )
       #else
-        #define Z_MOVE_TEST !!current_block->steps[Z_AXIS]
+        #define Z_MOVE_TEST !!current_block->steps[C_AXIS]
       #endif
 
-      SET_BIT(axis_did_move, X_AXIS, X_MOVE_TEST);
-      SET_BIT(axis_did_move, Y_AXIS, Y_MOVE_TEST);
-      SET_BIT(axis_did_move, Z_AXIS, Z_MOVE_TEST);
-      SET_BIT(axis_did_move, E_AXIS, !!current_block->steps[E_AXIS]);
-      SET_BIT(axis_did_move, X_HEAD, !!current_block->steps[X_HEAD]);
-      SET_BIT(axis_did_move, Y_HEAD, !!current_block->steps[Y_HEAD]);
-      SET_BIT(axis_did_move, Z_HEAD, !!current_block->steps[Z_HEAD]);
+      SET_BIT_TO(axis_did_move, X_AXIS, X_MOVE_TEST);
+      SET_BIT_TO(axis_did_move, Y_AXIS, Y_MOVE_TEST);
+      SET_BIT_TO(axis_did_move, Z_AXIS, Z_MOVE_TEST);
+      //SET_BIT_TO(axis_did_move, E_AXIS, !!current_block->steps[E_AXIS]);
+      //SET_BIT_TO(axis_did_move, X_HEAD, !!current_block->steps[A_AXIS]);
+      //SET_BIT_TO(axis_did_move, Y_HEAD, !!current_block->steps[B_AXIS]);
+      //SET_BIT_TO(axis_did_move, Z_HEAD, !!current_block->steps[C_AXIS]);
 
       // Initialize the trapezoid generator from the current block.
       #if ENABLED(LIN_ADVANCE)