udivsi3.S revision 1.2 
1/*	$NetBSD: udivsi3.S,v 1.7 2006/05/22 20:56:44 uwe Exp $	*/
2
3/*-
4 * Copyright (c) 1990 The Regents of the University of California.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * William Jolitz.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 *	from: @(#)udivsi3.s	5.1 (Berkeley) 5/15/90
35 */
36
37#include <machine/asm.h>
38
39/*
40 * IMPORTANT: This function is special.
41 *
42 * This function is an auxiliary function that is referenced by the
43 * code generated by gcc for integer division.  But gcc does NOT treat
44 * a call to this function as an ordinary function call w.r.t. the set
45 * of register this call clobbers.  See the definition of "udivsi3_i1"
46 * in gcc/config/sh/sh.md.
47 *
48 * Any call to this function MUST NOT clobber any registers besides r4
49 * and r0, where the result is returned.  At the time of the call the
50 * r4 contains the first argument, so we are only left with r0, and we
51 * cannot do anything meaningful using only one register.  The
52 * consequences are:
53 *
54 * . this function cannot have _PROF_PROLOGUE
55 * . this function cannot be called via PLT
56 */
57
58
59/* r0 <= r4 / r5 */
60NENTRY(__udivsi3)
61	tst	r5, r5
62	bt	div_by_zero
63
64	mov	#0, r0
65	div0u
66#define DIVSTEP	rotcl r4; div1 r5, r0
67	/* repeat 32 times */
68	DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
69	DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
70	DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
71	DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
72#undef DIVSTEP
73	rotcl	r4
74
75	rts
76	 mov	r4, r0
77
78div_by_zero:
79#ifdef _KERNEL
80	rts
81	 mov	#0, r0
82#else
83	mov.l	r14, @-r15
84	sts.l	pr, @-r15
85	mov	r15, r14
86
87	mov.l	L_raise, r1
88#ifdef PIC
891:	bsrf	r1
90#else
91	jsr	@r1
92#endif
93	 mov	#8, r4		/* delay slot.  8 <- SIGFPE. */
94	mov	#0, r0
95
96	lds.l	@r15+, pr
97	rts
98	 mov.l	@r15+, r14
99
100	.align	2
101L_raise:
102#ifdef PIC
103	.long	_C_LABEL(raise)-(1b+4)
104#else
105	.long	_C_LABEL(raise)
106#endif
107#endif
108