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CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v102a/clib/sbrk.c

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+/***************************************************************************
+ *									    
+ *			     s b r k   F u n c t i o n			    
+ *			     -------------------------			    
+ *	Copyright 1982 by Digital Research Inc.  All rights reserved.       
+ *									    
+ *	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		    
+ *									    
+ *	Last modified:
+ *	1/84 whf	refresh include files for 68K (sbrk in asm for 8086)
+ ****************************************************************************/
+#include "portab.h"
+#include "osif.h"
+#include "osiferr.h"
+#include "errno.h"
+						/****************************/
+EXTERN	BYTE	*_break;			/* Old break address	    */
+						/****************************/
+BYTE *	sbrk(incr)				/* CLEAR FUNCTION ***********/
+	WORD	incr;				/* Incremental storage	    */
+						/*			    */
+{						/****************************/
+REG	BYTE	*t1,*t2;			/* Temporary		    */
+REG	LONG	inc;				/* Temp size increment	    */
+	inc = ((LONG)incr) & 0xffffL;		/* Un sign-extend	    */
+	if(inc & 1)				/* Disallow odd incr's	    */
+		inc++;				/* Round up to next	    */
+						/*			    */
+	t1 = _break;				/* Save the old break	    */
+	t2 = _break + inc;			/* New break value	    */
+						/****************************/
+	if(brk(t2) == FAILURE)			/* Allocate		    */
+		RETERR(FAILURE,ENOMEM);		/*	Can't		    */
+						/****************************/
+	return(t1);				/* And return		    */
+}						/****************************/