#include	"defs.h"

#define	SLOP 0100
#define	HEAPINC 04000
ADR	heapmin, heapmax;	/* used for space allocation */
ADR	heapnxt;
ERR	heaperr;

heaprnd(s) POS s;
{
	heapnxt += (s+sizeof(ADR))&~(sizeof(ADR)-1);
}

ADR getheap(s)
	POS	s;
{
	REG POS end;

	IF heapnxt == nil(ADR)
	THEN	heapmax = heapmin = heapnxt = sbrk(0);
	FI

	end = round(heapnxt+s, SLOP);
	IF adr(end)>=heapmax
	THEN	IF brk(adr(end)+HEAPINC) == adr(-1)
		THEN	longjmp(heaperr, 1);
		ELSE	heapmax=adr(end)+HEAPINC;
		FI
	FI
	return(heapnxt);
}

ADR heap(s)
	POS	s;
{
	REG ADR r=getheap(s);
	heaprnd(s);
	return(r);
}

ADR setheap(s)
	ADR s;
{
	return(brk(s));
}