/	wdptr = alloca(nbytes);
/ like alloc, but automatic
/ automatic free upon return from calling function

.globl _alloca
_alloca:
	mov	(sp)+,r1	/ return
	mov	(sp),r0		/ count
	inc	r0
	bic	$1,r0		/ round up
	sub	r0,sp		/ take core
	mov	sp,r0
	tst	(r0)+		/ returned value; will generate
				/ a memory fault if there isn't enough core
	jmp	(r1)