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udiv.S revision 1.1 
      1 /*-
      2  * Copyright (c) 1991, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * This code is derived from software contributed to Berkeley by
      6  * Donn Seeley at UUNET Technologies, Inc.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. Neither the name of the University nor the names of its contributors
     17  *    may be used to endorse or promote products derived from this software
     18  *    without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     30  * SUCH DAMAGE.
     31  */
     32 
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 	/* .asciz "@(#)udiv.s	8.1 (Berkeley) 6/4/93" */
     35 	.asciz "$NetBSD: udiv.S,v 1.1 2005/12/20 19:28:50 christos Exp $"
     36 #endif /* LIBC_SCCS and not lint */
     37 
     38 /*
     39  * Unsigned division, PCC flavor.
     40  * udiv() takes an ordinary dividend/divisor pair;
     41  * audiv() takes a pointer to a dividend and an ordinary divisor.
     42  */
     43 
     44 #include "DEFS.h"
     45 
     46 #define	DIVIDEND	4(%ap)
     47 #define	DIVISOR		8(%ap)
     48 
     49 #ifdef __ELF__
     50 ASENTRY(__udiv,0)
     51 #else
     52 ASENTRY(udiv,0)
     53 #endif
     54 	movl	DIVISOR,%r2
     55 	jlss	Leasy		# big divisor: settle by comparison
     56 	movl	DIVIDEND,%r0
     57 	jlss	Lhard		# big dividend: extended division
     58 	divl2	%r2,%r0		# small divisor and dividend: signed division
     59 	ret
     60 Lhard:
     61 	clrl	%r1
     62 	ediv	%r2,%r0,%r0,%r1
     63 	ret
     64 Leasy:
     65 	cmpl	DIVIDEND,%r2
     66 	jgequ	Lone		# if dividend is as big or bigger, return 1
     67 	clrl	%r0		# else return 0
     68 	ret
     69 Lone:
     70 	movl	$1,%r0
     71 	ret
     72 
     73 #ifdef __ELF__
     74 ASENTRY(__audiv,0)
     75 #else
     76 ASENTRY(audiv,0)
     77 #endif
     78 	movl	DIVIDEND,%r3
     79 	movl	DIVISOR,%r2
     80 	jlss	La_easy		# big divisor: settle by comparison
     81 	movl	(%r3),%r0
     82 	jlss	La_hard		# big dividend: extended division
     83 	divl2	%r2,%r0		# small divisor and dividend: signed division
     84 	movl	%r0,(%r3)		# leave the value of the assignment in %r0
     85 	ret
     86 La_hard:
     87 	clrl	%r1
     88 	ediv	%r2,%r0,%r0,%r1
     89 	movl	%r0,(%r3)
     90 	ret
     91 La_easy:
     92 	cmpl	(%r3),%r2
     93 	jgequ	La_one		# if dividend is as big or bigger, return 1
     94 	clrl	%r0		# else return 0
     95 	clrl	(%r3)
     96 	ret
     97 La_one:
     98 	movl	$1,%r0
     99 	movl	%r0,(%r3)
    100 	ret
    101