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Digital-Research-Source-Code/CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v102a/clib/sbrk.c
Sepp J Morris 31738079c4 Upload
Digital Research
2020-11-06 18:50:37 +01:00

48 lines
1.8 KiB
C

/***************************************************************************
*
* 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 */
} /****************************/