From d0c3744f927782565d14b47184781e889c09d74e Mon Sep 17 00:00:00 2001
From: Michael Moon <triffid.hunter@gmail.com>
Date: Mon, 18 Oct 2010 18:43:03 +1100
Subject: [PATCH] add flush queue for emergency stop

---
 dda_queue.c     | 15 +++++++++++++++
 dda_queue.h     |  3 +++
 gcode_process.c |  1 +
 3 files changed, 19 insertions(+)

diff --git a/dda_queue.c b/dda_queue.c
index 71e3c3a..fb3edb2 100644
--- a/dda_queue.c
+++ b/dda_queue.c
@@ -106,3 +106,18 @@ void print_queue() {
 		serial_writechar('E');
 	serial_writechar('\n');
 }
+
+void queue_flush() {
+	// save interrupt flag
+	uint8_t sreg = SREG;
+
+	// disable interrupts
+	cli();
+
+	// flush queue
+	mb_tail = mb_head;
+	movebuffer[mb_head].live = 0;
+
+	// restore interrupt flag
+	SREG = sreg;
+}
diff --git a/dda_queue.h b/dda_queue.h
index 9edf865..46b4a4f 100644
--- a/dda_queue.h
+++ b/dda_queue.h
@@ -33,4 +33,7 @@ void next_move(void) __attribute__ ((hot));
 // print queue status
 void print_queue(void);
 
+// flush the queue for eg; emergency stop
+void queue_flush(void);
+
 #endif	/* _DDA_QUEUE */
diff --git a/gcode_process.c b/gcode_process.c
index 2ced51b..789fd12 100644
--- a/gcode_process.c
+++ b/gcode_process.c
@@ -249,6 +249,7 @@ void process_gcode_command() {
 				// M112- immediate stop
 			case 112:
 				disableTimerInterrupt();
+				queue_flush();
 				power_off();
 				break;
 				// M113- extruder PWM