eliminated an abstraction violation where motion_control needed position information from the planner (untested)

gcode.c

@@ -388,7 +388,8 @@ uint8_t gc_execute_line(char *line) {
       double depth = target[gc.plane_axis_2]-gc.position[gc.plane_axis_2];
       // Trace the arc
       mc_arc(theta_start, angular_travel, radius, depth, gc.plane_axis_0, gc.plane_axis_1, gc.plane_axis_2, 
-        (gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode);
+        (gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode,
+        gc.position);
       // Finish off with a line to make sure we arrive exactly where we think we are
       mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], 
         (gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode);

motion_control.c

@@ -48,14 +48,13 @@ void mc_dwell(uint32_t milliseconds)
 // positive angular_travel means clockwise, negative means counterclockwise. Radius == the radius of the
 // circle in millimeters. axis_1 and axis_2 selects the circle plane in tool space. Stick the remaining
 // axis in axis_l which will be the axis for linear travel if you are tracing a helical motion.
+// position is a pointer to a vector representing the current position in millimeters.
 
 // The arc is approximated by generating a huge number of tiny, linear segments. The length of each 
 // segment is configured in settings.mm_per_arc_segment.  
 void mc_arc(double theta, double angular_travel, double radius, double linear_travel, int axis_1, int axis_2, 
-  int axis_linear, double feed_rate, int invert_feed_rate)
+  int axis_linear, double feed_rate, int invert_feed_rate, double *position)
 {      
-  int32_t position[3];
-  plan_get_position_steps(&position);
   int acceleration_manager_was_enabled = plan_is_acceleration_manager_enabled();
   plan_set_acceleration_manager_enabled(FALSE); // disable acceleration management for the duration of the arc
   double millimeters_of_travel = hypot(angular_travel*radius, labs(linear_travel));
@@ -70,13 +69,13 @@ void mc_arc(double theta, double angular_travel, double radius, double linear_tr
   // The linear motion for each segment
   double linear_per_segment = linear_travel/segments;
   // Compute the center of this circle
-  double center_x = (position[axis_1]/settings.steps_per_mm[axis_1])-sin(theta)*radius;
-  double center_y = (position[axis_2]/settings.steps_per_mm[axis_2])-cos(theta)*radius;
+  double center_x = position[axis_1]-sin(theta)*radius;
+  double center_y = position[axis_2]-cos(theta)*radius;
   // a vector to track the end point of each segment
   double target[3];
   int i;
   // Initialize the linear axis
-  target[axis_linear] = position[axis_linear]/settings.steps_per_mm[axis_linear];
+  target[axis_linear] = position[axis_linear];
   for (i=0; i<=segments; i++) {
     target[axis_linear] += linear_per_segment;
     theta += theta_per_segment;

motion_control.h

@@ -37,7 +37,7 @@
 // circle in millimeters. axis_1 and axis_2 selects the circle plane in tool space. Stick the remaining
 // axis in axis_l which will be the axis for linear travel if you are tracing a helical motion.
 void mc_arc(double theta, double angular_travel, double radius, double linear_travel, int axis_1, int axis_2, 
-  int axis_linear, double feed_rate, int invert_feed_rate);
+  int axis_linear, double feed_rate, int invert_feed_rate, double *position);
   
 // Dwell for a couple of time units
 void mc_dwell(uint32_t milliseconds);

planner.c

@@ -412,7 +412,3 @@ void plan_buffer_line(double x, double y, double z, double feed_rate, int invert
   st_wake_up();
 }
 
-void plan_get_position_steps(int32_t (*vector)[3]) {
-  memcpy(vector, position, sizeof(position)); // vector[] = position[]
-}
-

planner.h

@@ -74,7 +74,4 @@ void plan_set_acceleration_manager_enabled(int enabled);
 // Is acceleration-management currently enabled?
 int plan_is_acceleration_manager_enabled();
 
-// Copy the current absolute position in steps into the provided vector
-void plan_get_position_steps(int32_t (*vector)[3]);
-
 #endif