Upload

Digital Research

CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v101/klib/sbrk.c

@@ -0,0 +1,40 @@
+/****************************************************************************/
+/*									    */
+/*			     s b r k   F u n c t i o n			    */
+/*			     -------------------------			    */
+/*									    */
+/*	The "sbrk" function is used to allocate memory dynamically.	    */
+/*									    */
+/*	Calling Sequence:						    */
+/*									    */
+/*		addr = sbrk(incr);					    */
+/*									    */
+/*	Where:								    */
+/*		incr	Is the incremental number of bytes to be added to   */
+/*			the program heap area.				    */
+/*									    */
+/*		addr	Is the beginning address of the allocated area.	    */
+/*			-1 is returned if allocation failed		    */
+/*									    */
+/****************************************************************************/
+#include "stdio.h"
+#include "cpm.h"
+EXTERN	BYTE	*_break;			/* Old break address	    */
+						/****************************/
+BYTE	*sbrk(incr)				/*			    */
+	WORD	incr;				/* Incremental storage	    */
+						/*			    */
+{						/****************************/
+REG	BYTE	*t1;				/* Temporary		    */
+	if(incr & 1)				/* Disallow odd incr's	    */
+		incr++;				/* Round up to next	    */
+						/*			    */
+	t1 = _break + incr;			/* New break value	    */
+						/****************************/
+	if(brk(t1) == FAILURE)			/* Allocate		    */
+		return(FAILURE);		/*	Can't		    */
+						/****************************/
+	t1 = _break;				/* Save old break	    */
+	_break += incr;				/* Set new break	    */
+	return(t1);				/* And return		    */
+}						/****************************/