From: utzoo!decvax!cca!jfw.mit-ccc@Mit-Mc@sri-unix
Newsgroups: net.unix-wizards
Title: pcc and uldiv for V7 PDP11
Article-I.D.: sri-unix.4293
Posted: Sun Nov 21 21:28:36 1982
Received: Mon Nov 22 04:49:42 1982

Date: 19 Nov 1982 16:12:41-EST
uldiv and ulrem are generated by the PCC when it compiles something involving
unsigned longs.  They are analogous to ldiv and lrem.  If you have floating
point, I long ago wrote the routines to do what uldiv and ulrem are to do.

/**** uldiv.c, by John Woods, October 9, 1982 ****/

unsigned long uldiv(a,b) unsigned long a,b; {
	return((unsigned long)((double)a / (double)b));
}
unsigned long auldiv(a,b) unsigned long *a,b; {
	return(*a = ((unsigned long)((double)*a / (double)b)));
}
unsigned long ulmul(a,b) unsigned long a,b; {
	return((unsigned long)((double)a * (double)b));
}
unsigned long aulmul(a,b) unsigned long *a,b; {
	return(*a = ((unsigned long)((double)*a * (double)b)));
}
/****************/

The following is a massaged assembly language version which avoids some of the
overhead of C procedure discipline:  (It was compiled -S by PCC and -O'd by me).

/**** uldiv.s, by John Woods, October 9, 1982 ****/
 .text
 .globl	uldiv
uldiv:
/	line 2, file "uldiv.c"
	setl
	movif	2.(sp),fr0
	cfcc
	bpl	1f
	addf	$050200,fr0
1:
	movif	6.(sp),fr1
	cfcc
	bpl	1f
	addf	$050200,fr1
1:
	divf	fr1,fr0
	movfi	fr0,-(sp)
	seti
	mov	(sp)+,r0
	mov	(sp)+,r1
	rts	pc
 .globl	fltused
 .globl	auldiv
auldiv:
/	line 5, file "uldiv.c"
	mov	2.(sp),r1
	mov	(r1)+,r0
	mov	(r1),r1
	mov	r1,-(sp)
	mov	r0,-(sp)
	setl
	movif	(sp)+,fr0
	cfcc
	bpl	1f
	addf	$050200,fr0
1:
	movif	4.(sp),fr1
	cfcc
	bpl	1f
	addf	$050200,fr1
1:
	divf	fr1,fr0
	movfi	fr0,-(sp)
	seti
	mov	(sp)+,r0
	mov	(sp)+,r1
	mov	2.(sp),r2
	mov	r0,(r2)+
	mov	r1,(r2)
	rts	pc
 .globl	fltused
 .globl	ulmul
ulmul:
/	line 8, file "uldiv.c"
	setl
	movif	2.(sp),fr0
	seti
	cfcc
	bpl	1f
	addf	$050200,fr0
1:
	setl
	movif	6.(sp),fr1
	cfcc
	bpl	1f
	addf	$050200,fr1
1:
	mulf	fr1,fr0
	movfi	fr0,-(sp)
	seti
	mov	(sp)+,r0
	mov	(sp)+,r1
	rts	pc
 .globl	fltused
 .globl	aulmul
aulmul:
/	line 11, file "uldiv.c"
	mov	2.(sp),r1
	mov	(r1)+,r0
	mov	(r1),r1
	mov	r1,-(sp)
	mov	r0,-(sp)
	setl
	movif	(sp)+,fr0
	cfcc
	bpl	1f
	addf	$050200,fr0
1:
	setl
	movif	4.(sp),fr1
	cfcc
	bpl	1f
	addf	$050200,fr1
1:
	mulf	fr1,fr0
	movfi	fr0,-(sp)
	seti
	mov	(sp)+,r0
	mov	(sp)+,r1
	mov	2.(sp),r2
	mov	r0,(r2)+
	mov	r1,(r2)
	rts	pc
 .globl	fltused
 .data