File re-organization. New Makefile.

- Re-organized source code files into a ‘grbl’ directory to lessen one
step in compiling Grbl through the Arduino IDE.

- Added an ‘examples’ directory with an upload .INO sketch to further
simplify compiling and uploading Grbl via the Arduino IDE.

- Updated the Makefile with regard to the source code no longer being
in the root directory. All files generated by compiling is placed in a
separate ‘build’ directory to keep things tidy. The makefile should
operate in the same way as it did before.

grbl/planner.h

@@ -0,0 +1,102 @@
+/*
+  planner.h - buffers movement commands and manages the acceleration profile plan
+  Part of Grbl v0.9
+
+  Copyright (c) 2012-2015 Sungeun K. Jeon 
+
+  Grbl 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.
+
+  Grbl 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 Grbl.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/* 
+  This file is based on work from Grbl v0.8, distributed under the 
+  terms of the MIT-license. See COPYING for more details.  
+    Copyright (c) 2009-2011 Simen Svale Skogsrud
+    Copyright (c) 2011-2012 Sungeun K. Jeon
+*/ 
+
+#ifndef planner_h
+#define planner_h
+
+
+// The number of linear motions that can be in the plan at any give time
+#ifndef BLOCK_BUFFER_SIZE
+  #ifdef USE_LINE_NUMBERS
+    #define BLOCK_BUFFER_SIZE 16
+  #else
+    #define BLOCK_BUFFER_SIZE 18
+  #endif
+#endif
+
+// This struct stores a linear movement of a g-code block motion with its critical "nominal" values
+// are as specified in the source g-code. 
+typedef struct {
+  // Fields used by the bresenham algorithm for tracing the line
+  // NOTE: Used by stepper algorithm to execute the block correctly. Do not alter these values.
+  uint8_t direction_bits;    // The direction bit set for this block (refers to *_DIRECTION_BIT in config.h)
+  uint32_t steps[N_AXIS];    // Step count along each axis
+  uint32_t step_event_count; // The maximum step axis count and number of steps required to complete this block. 
+
+  // Fields used by the motion planner to manage acceleration
+  float entry_speed_sqr;         // The current planned entry speed at block junction in (mm/min)^2
+  float max_entry_speed_sqr;     // Maximum allowable entry speed based on the minimum of junction limit and 
+                                 //   neighboring nominal speeds with overrides in (mm/min)^2
+  float max_junction_speed_sqr;  // Junction entry speed limit based on direction vectors in (mm/min)^2
+  float nominal_speed_sqr;       // Axis-limit adjusted nominal speed for this block in (mm/min)^2
+  float acceleration;            // Axis-limit adjusted line acceleration in (mm/min^2)
+  float millimeters;             // The remaining distance for this block to be executed in (mm)
+  // uint8_t max_override;       // Maximum override value based on axis speed limits
+
+  #ifdef USE_LINE_NUMBERS
+    int32_t line_number;
+  #endif
+} plan_block_t;
+
+      
+// Initialize and reset the motion plan subsystem
+void plan_reset();
+
+// Add a new linear movement to the buffer. target[N_AXIS] is the signed, absolute target position 
+// in millimeters. Feed rate specifies the speed of the motion. If feed rate is inverted, the feed
+// rate is taken to mean "frequency" and would complete the operation in 1/feed_rate minutes.
+#ifdef USE_LINE_NUMBERS
+  void plan_buffer_line(float *target, float feed_rate, uint8_t invert_feed_rate, int32_t line_number);
+#else
+  void plan_buffer_line(float *target, float feed_rate, uint8_t invert_feed_rate);
+#endif
+
+// Called when the current block is no longer needed. Discards the block and makes the memory
+// availible for new blocks.
+void plan_discard_current_block();
+
+// Gets the current block. Returns NULL if buffer empty
+plan_block_t *plan_get_current_block();
+
+// Called periodically by step segment buffer. Mostly used internally by planner.
+uint8_t plan_next_block_index(uint8_t block_index);
+
+// Called by step segment buffer when computing executing block velocity profile.
+float plan_get_exec_block_exit_speed();
+
+// Reset the planner position vector (in steps)
+void plan_sync_position();
+
+// Reinitialize plan with a partially completed block
+void plan_cycle_reinitialize();
+
+// Returns the number of active blocks are in the planner buffer.
+uint8_t plan_get_block_buffer_count();
+
+// Returns the status of the block ring buffer. True, if buffer is full.
+uint8_t plan_check_full_buffer();
+
+#endif