getstk.c,v

来自「TCP-IP红宝书源代码」· C,V 代码 · 共 102 行

head	1.3;
access;
symbols;
locks
	dls:1.3; strict;
comment	@ * @;


1.3
date	97.09.21.19.29.30;	author dls;	state Dist;
branches;
next	1.2;

1.2
date	94.05.06.03.12.23;	author dls;	state Works;
branches;
next	1.1;

1.1
date	94.05.01.16.07.01;	author dls;	state Works;
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next	;


desc
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1.3
log
@pre-3e code
@
text
@/* getstk.c - getstk */

#include <conf.h>
#include <kernel.h>
#include <mem.h>

/*------------------------------------------------------------------------
 * getstk  --  allocate stack memory, returning address of topmost WORD
 *------------------------------------------------------------------------
 */
WORD	*getstk(nbytes)
	unsigned  int nbytes;
{
	STATWORD ps;    
	struct	mblock	*p, *q;	/* q follows p along memlist		*/
	struct	mblock	*fits, *fitsq;
	WORD	len;

	disable(ps);
	if (nbytes == 0) {
		restore(ps);
		return( (WORD *)SYSERR );
	}
	nbytes = (unsigned int) roundew(nbytes);
	fits = (struct mblock *) NULL;
	q = &memlist;
	for (p = q->mnext ; p !=(struct mblock *) NULL ; q = p,p = p->mnext)
		if ( p->mlen >= nbytes) {
			fitsq = q;
			fits = p;
		}
	if (fits == (struct mblock *) NULL) {
		restore(ps);
		return( (WORD *)SYSERR );
	}
	if (nbytes == (len = fits->mlen) ) {
		fitsq->mnext = fits->mnext;
	} else {
		fits->mlen -= nbytes;
	}
	fits = (struct mblock *) ((WORD) fits + len - sizeof(WORD));
	*((WORD *) fits) = nbytes;
	restore(ps);
	return( (WORD *) fits);
}
@


1.2
log
@*** empty log message ***
@
text
@a35 1
kprintf("in getstk, fits %d (%X) len %d\n", fits, fits, fits->mlen);
a41 1
kprintf("in getstk, fits to return %d (%X)\n", fits, fits);
@


1.1
log
@Initial revision
@
text
@d36 1
d43 1
@