Import grbl v1.1h
diff --git a/grbl/gcode.h b/grbl/gcode.h
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--- /dev/null
+++ b/grbl/gcode.h
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+/*
+  gcode.h - rs274/ngc parser.
+  Part of Grbl
+
+  Copyright (c) 2011-2016 Sungeun K. Jeon for Gnea Research LLC
+  Copyright (c) 2009-2011 Simen Svale Skogsrud
+
+  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/>.
+*/
+
+#ifndef gcode_h
+#define gcode_h
+
+
+// Define modal group internal numbers for checking multiple command violations and tracking the
+// type of command that is called in the block. A modal group is a group of g-code commands that are
+// mutually exclusive, or cannot exist on the same line, because they each toggle a state or execute
+// a unique motion. These are defined in the NIST RS274-NGC v3 g-code standard, available online,
+// and are similar/identical to other g-code interpreters by manufacturers (Haas,Fanuc,Mazak,etc).
+// NOTE: Modal group define values must be sequential and starting from zero.
+#define MODAL_GROUP_G0 0 // [G4,G10,G28,G28.1,G30,G30.1,G53,G92,G92.1] Non-modal
+#define MODAL_GROUP_G1 1 // [G0,G1,G2,G3,G38.2,G38.3,G38.4,G38.5,G80] Motion
+#define MODAL_GROUP_G2 2 // [G17,G18,G19] Plane selection
+#define MODAL_GROUP_G3 3 // [G90,G91] Distance mode
+#define MODAL_GROUP_G4 4 // [G91.1] Arc IJK distance mode
+#define MODAL_GROUP_G5 5 // [G93,G94] Feed rate mode
+#define MODAL_GROUP_G6 6 // [G20,G21] Units
+#define MODAL_GROUP_G7 7 // [G40] Cutter radius compensation mode. G41/42 NOT SUPPORTED.
+#define MODAL_GROUP_G8 8 // [G43.1,G49] Tool length offset
+#define MODAL_GROUP_G12 9 // [G54,G55,G56,G57,G58,G59] Coordinate system selection
+#define MODAL_GROUP_G13 10 // [G61] Control mode
+
+#define MODAL_GROUP_M4 11  // [M0,M1,M2,M30] Stopping
+#define MODAL_GROUP_M7 12 // [M3,M4,M5] Spindle turning
+#define MODAL_GROUP_M8 13 // [M7,M8,M9] Coolant control
+#define MODAL_GROUP_M9 14 // [M56] Override control
+
+// Define command actions for within execution-type modal groups (motion, stopping, non-modal). Used
+// internally by the parser to know which command to execute.
+// NOTE: Some macro values are assigned specific values to make g-code state reporting and parsing 
+// compile a litte smaller. Necessary due to being completely out of flash on the 328p. Although not
+// ideal, just be careful with values that state 'do not alter' and check both report.c and gcode.c 
+// to see how they are used, if you need to alter them.
+
+// Modal Group G0: Non-modal actions
+#define NON_MODAL_NO_ACTION 0 // (Default: Must be zero)
+#define NON_MODAL_DWELL 4 // G4 (Do not alter value)
+#define NON_MODAL_SET_COORDINATE_DATA 10 // G10 (Do not alter value)
+#define NON_MODAL_GO_HOME_0 28 // G28 (Do not alter value)
+#define NON_MODAL_SET_HOME_0 38 // G28.1 (Do not alter value)
+#define NON_MODAL_GO_HOME_1 30 // G30 (Do not alter value)
+#define NON_MODAL_SET_HOME_1 40 // G30.1 (Do not alter value)
+#define NON_MODAL_ABSOLUTE_OVERRIDE 53 // G53 (Do not alter value)
+#define NON_MODAL_SET_COORDINATE_OFFSET 92 // G92 (Do not alter value)
+#define NON_MODAL_RESET_COORDINATE_OFFSET 102 //G92.1 (Do not alter value)
+
+// Modal Group G1: Motion modes
+#define MOTION_MODE_SEEK 0 // G0 (Default: Must be zero)
+#define MOTION_MODE_LINEAR 1 // G1 (Do not alter value)
+#define MOTION_MODE_CW_ARC 2  // G2 (Do not alter value)
+#define MOTION_MODE_CCW_ARC 3  // G3 (Do not alter value)
+#define MOTION_MODE_PROBE_TOWARD 140 // G38.2 (Do not alter value)
+#define MOTION_MODE_PROBE_TOWARD_NO_ERROR 141 // G38.3 (Do not alter value)
+#define MOTION_MODE_PROBE_AWAY 142 // G38.4 (Do not alter value)
+#define MOTION_MODE_PROBE_AWAY_NO_ERROR 143 // G38.5 (Do not alter value)
+#define MOTION_MODE_NONE 80 // G80 (Do not alter value)
+
+// Modal Group G2: Plane select
+#define PLANE_SELECT_XY 0 // G17 (Default: Must be zero)
+#define PLANE_SELECT_ZX 1 // G18 (Do not alter value)
+#define PLANE_SELECT_YZ 2 // G19 (Do not alter value)
+
+// Modal Group G3: Distance mode
+#define DISTANCE_MODE_ABSOLUTE 0 // G90 (Default: Must be zero)
+#define DISTANCE_MODE_INCREMENTAL 1 // G91 (Do not alter value)
+
+// Modal Group G4: Arc IJK distance mode
+#define DISTANCE_ARC_MODE_INCREMENTAL 0 // G91.1 (Default: Must be zero)
+
+// Modal Group M4: Program flow
+#define PROGRAM_FLOW_RUNNING 0 // (Default: Must be zero)
+#define PROGRAM_FLOW_PAUSED 3 // M0
+#define PROGRAM_FLOW_OPTIONAL_STOP 1 // M1 NOTE: Not supported, but valid and ignored.
+#define PROGRAM_FLOW_COMPLETED_M2  2 // M2 (Do not alter value)
+#define PROGRAM_FLOW_COMPLETED_M30 30 // M30 (Do not alter value)
+
+// Modal Group G5: Feed rate mode
+#define FEED_RATE_MODE_UNITS_PER_MIN  0 // G94 (Default: Must be zero)
+#define FEED_RATE_MODE_INVERSE_TIME   1 // G93 (Do not alter value)
+
+// Modal Group G6: Units mode
+#define UNITS_MODE_MM 0 // G21 (Default: Must be zero)
+#define UNITS_MODE_INCHES 1 // G20 (Do not alter value)
+
+// Modal Group G7: Cutter radius compensation mode
+#define CUTTER_COMP_DISABLE 0 // G40 (Default: Must be zero)
+
+// Modal Group G13: Control mode
+#define CONTROL_MODE_EXACT_PATH 0 // G61 (Default: Must be zero)
+
+// Modal Group M7: Spindle control
+#define SPINDLE_DISABLE 0 // M5 (Default: Must be zero)
+#define SPINDLE_ENABLE_CW   PL_COND_FLAG_SPINDLE_CW // M3 (NOTE: Uses planner condition bit flag)
+#define SPINDLE_ENABLE_CCW  PL_COND_FLAG_SPINDLE_CCW // M4 (NOTE: Uses planner condition bit flag)
+
+// Modal Group M8: Coolant control
+#define COOLANT_DISABLE 0 // M9 (Default: Must be zero)
+#define COOLANT_FLOOD_ENABLE  PL_COND_FLAG_COOLANT_FLOOD // M8 (NOTE: Uses planner condition bit flag)
+#define COOLANT_MIST_ENABLE   PL_COND_FLAG_COOLANT_MIST  // M7 (NOTE: Uses planner condition bit flag)
+
+// Modal Group G8: Tool length offset
+#define TOOL_LENGTH_OFFSET_CANCEL 0 // G49 (Default: Must be zero)
+#define TOOL_LENGTH_OFFSET_ENABLE_DYNAMIC 1 // G43.1
+
+// Modal Group M9: Override control
+#ifdef DEACTIVATE_PARKING_UPON_INIT
+  #define OVERRIDE_DISABLED  0 // (Default: Must be zero)
+  #define OVERRIDE_PARKING_MOTION 1 // M56
+#else
+  #define OVERRIDE_PARKING_MOTION 0 // M56 (Default: Must be zero)
+  #define OVERRIDE_DISABLED  1 // Parking disabled.
+#endif
+
+// Modal Group G12: Active work coordinate system
+// N/A: Stores coordinate system value (54-59) to change to.
+
+// Define parameter word mapping.
+#define WORD_F  0
+#define WORD_I  1
+#define WORD_J  2
+#define WORD_K  3
+#define WORD_L  4
+#define WORD_N  5
+#define WORD_P  6
+#define WORD_R  7
+#define WORD_S  8
+#define WORD_T  9
+#define WORD_X  10
+#define WORD_Y  11
+#define WORD_Z  12
+
+// Define g-code parser position updating flags
+#define GC_UPDATE_POS_TARGET   0 // Must be zero
+#define GC_UPDATE_POS_SYSTEM   1
+#define GC_UPDATE_POS_NONE     2
+
+// Define probe cycle exit states and assign proper position updating.
+#define GC_PROBE_FOUND      GC_UPDATE_POS_SYSTEM
+#define GC_PROBE_ABORT      GC_UPDATE_POS_NONE
+#define GC_PROBE_FAIL_INIT  GC_UPDATE_POS_NONE
+#define GC_PROBE_FAIL_END   GC_UPDATE_POS_TARGET
+#ifdef SET_CHECK_MODE_PROBE_TO_START
+  #define GC_PROBE_CHECK_MODE   GC_UPDATE_POS_NONE  
+#else
+  #define GC_PROBE_CHECK_MODE   GC_UPDATE_POS_TARGET
+#endif
+
+// Define gcode parser flags for handling special cases.
+#define GC_PARSER_NONE                  0 // Must be zero.
+#define GC_PARSER_JOG_MOTION            bit(0)
+#define GC_PARSER_CHECK_MANTISSA        bit(1)
+#define GC_PARSER_ARC_IS_CLOCKWISE      bit(2)
+#define GC_PARSER_PROBE_IS_AWAY         bit(3)
+#define GC_PARSER_PROBE_IS_NO_ERROR     bit(4)
+#define GC_PARSER_LASER_FORCE_SYNC      bit(5)
+#define GC_PARSER_LASER_DISABLE         bit(6)
+#define GC_PARSER_LASER_ISMOTION        bit(7)
+
+
+// NOTE: When this struct is zeroed, the above defines set the defaults for the system.
+typedef struct {
+  uint8_t motion;          // {G0,G1,G2,G3,G38.2,G80}
+  uint8_t feed_rate;       // {G93,G94}
+  uint8_t units;           // {G20,G21}
+  uint8_t distance;        // {G90,G91}
+  // uint8_t distance_arc; // {G91.1} NOTE: Don't track. Only default supported.
+  uint8_t plane_select;    // {G17,G18,G19}
+  // uint8_t cutter_comp;  // {G40} NOTE: Don't track. Only default supported.
+  uint8_t tool_length;     // {G43.1,G49}
+  uint8_t coord_select;    // {G54,G55,G56,G57,G58,G59}
+  // uint8_t control;      // {G61} NOTE: Don't track. Only default supported.
+  uint8_t program_flow;    // {M0,M1,M2,M30}
+  uint8_t coolant;         // {M7,M8,M9}
+  uint8_t spindle;         // {M3,M4,M5}
+  uint8_t override;        // {M56}
+} gc_modal_t;
+
+typedef struct {
+  float f;         // Feed
+  float ijk[3];    // I,J,K Axis arc offsets
+  uint8_t l;       // G10 or canned cycles parameters
+  int32_t n;       // Line number
+  float p;         // G10 or dwell parameters
+  // float q;      // G82 peck drilling
+  float r;         // Arc radius
+  float s;         // Spindle speed
+  uint8_t t;       // Tool selection
+  float xyz[3];    // X,Y,Z Translational axes
+} gc_values_t;
+
+
+typedef struct {
+  gc_modal_t modal;
+
+  float spindle_speed;          // RPM
+  float feed_rate;              // Millimeters/min
+  uint8_t tool;                 // Tracks tool number. NOT USED.
+  int32_t line_number;          // Last line number sent
+
+  float position[N_AXIS];       // Where the interpreter considers the tool to be at this point in the code
+
+  float coord_system[N_AXIS];    // Current work coordinate system (G54+). Stores offset from absolute machine
+                                 // position in mm. Loaded from EEPROM when called.
+  float coord_offset[N_AXIS];    // Retains the G92 coordinate offset (work coordinates) relative to
+                                 // machine zero in mm. Non-persistent. Cleared upon reset and boot.
+  float tool_length_offset;      // Tracks tool length offset value when enabled.
+} parser_state_t;
+extern parser_state_t gc_state;
+
+
+typedef struct {
+  uint8_t non_modal_command;
+  gc_modal_t modal;
+  gc_values_t values;
+} parser_block_t;
+
+
+// Initialize the parser
+void gc_init();
+
+// Execute one block of rs275/ngc/g-code
+uint8_t gc_execute_line(char *line);
+
+// Set g-code parser position. Input in steps.
+void gc_sync_position();
+
+#endif