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/* $OpenBSD: urem.S,v 1.5 2005/08/07 16:40:15 espie Exp $ */
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Donn Seeley at UUNET Technologies, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "DEFS.h"
/*
* Unsigned modulus, PCC flavor.
* urem() takes an ordinary dividend/divisor pair;
* aurem() takes a pointer to a dividend and an ordinary divisor.
*/
#define DIVIDEND 4(ap)
#define DIVISOR 8(ap)
ASENTRY(urem,R2)
movl DIVISOR,r2
jlss Leasy # big divisor: settle by comparison
movl DIVIDEND,r0
jlss Lhard # big dividend: need extended division
divl3 r2,r0,r1 # small divisor and dividend: signed modulus
mull2 r2,r1
subl2 r1,r0
ret
Lhard:
clrl r1
ediv r2,r0,r1,r0
ret
Leasy:
subl3 r2,DIVIDEND,r0
jcc Ldifference # if divisor goes in once, return difference
movl DIVIDEND,r0 # if divisor is bigger, return dividend
Ldifference:
ret
ASENTRY(aurem,R2|R3)
movl DIVIDEND,r3
movl DIVISOR,r2
jlss La_easy # big divisor: settle by comparison
movl (r3),r0
jlss La_hard # big dividend: need extended division
divl3 r2,r0,r1 # small divisor and dividend: signed modulus
mull2 r2,r1
subl2 r1,r0
movl r0,(r3) # leave the value of the assignment in r0
ret
La_hard:
clrl r1
ediv r2,r0,r1,r0
movl r0,(r3)
ret
La_easy:
subl3 r2,(r3),r0
jcs La_dividend # if divisor is bigger, leave dividend alone
movl r0,(r3) # if divisor goes in once, store difference
ret
La_dividend:
movl (r3),r0
ret
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