minix/lib/libp/new.c
2005-04-21 14:53:53 +00:00

69 lines
1.4 KiB
C
Executable file

/* $Header$ */
/*
* (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
*
* This product is part of the Amsterdam Compiler Kit.
*
* Permission to use, sell, duplicate or disclose this software must be
* obtained in writing. Requests for such permissions may be sent to
*
* Dr. Andrew S. Tanenbaum
* Wiskundig Seminarium
* Vrije Universiteit
* Postbox 7161
* 1007 MC Amsterdam
* The Netherlands
*
*/
/* Author: J.W. Stevenson */
extern _sav();
extern _rst();
#define assert(x) /* nothing */
#define UNDEF 0x8000
struct adm {
struct adm *next;
int size;
};
struct adm *_lastp = 0;
struct adm *_highp = 0;
_new(n,pp) int n; struct adm **pp; {
struct adm *p,*q;
int *ptmp;
n = ((n+sizeof(*p)-1) / sizeof(*p)) * sizeof(*p);
if ((p = _lastp) != 0)
do {
q = p->next;
if (q->size >= n) {
assert(q->size%sizeof(adm) == 0);
if ((q->size -= n) == 0) {
if (p == q)
p = 0;
else
p->next = q->next;
if (q == _highp)
_highp = p;
}
_lastp = p;
p = (struct adm *)((char *)q + q->size);
q = (struct adm *)((char *)p + n);
goto initialize;
}
p = q;
} while (p != _lastp);
/*no free block big enough*/
_sav(&p);
q = (struct adm *)((char *)p + n);
_rst(&q);
initialize:
*pp = p;
ptmp = (int *)p;
while (ptmp < (int *)q)
*ptmp++ = UNDEF;
}