1/*	$NetBSD: udivsi3_i4i.S,v 1.1 2011/08/04 03:20:09 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#if defined(LIBC_SCCS)
39	RCSID("$NetBSD: udivsi3_i4i.S,v 1.1 2011/08/04 03:20:09 uwe Exp $")
40#endif
41
42/*
43 * IMPOTANT: This function is special.
44 *
45 * This function is an auxiliary "millicode" function that is
46 * referenced by the code generated by gcc for unsigned integer
47 * division.  But gcc does NOT treat a call to this function as an
48 * ordinary function call - it can clobber only R1, MACL and MACH.
49 *
50 * See the definition of "udivsi3_i4_int" in gcc/config/sh/sh.md
51 *
52 * As the consequence this function cannot be called via any
53 * indirection that assumes normal calling convention:
54 *
55 * . cannot have _PROF_PROLOGUE
56 * . cannot be called via PLT (not relevant for kernel)
57 *
58 * XXX: uwe: Older gcc used __udivsi3; newer uses __udivsi3_i4i - a
59 * heavily tuned version that is NOT compatible with __udivsi3 because
60 * it clobbers different registers.  We don't want to link the kernel
61 * against libgcc and we don't have resources to write heavily tuned
62 * version ourselves, so clone __udivsi3 but adjust the code to
63 * conform to the __udivsi3_i4i clobber spec.
64 */
65
66
67#ifdef __ELF__
68	.hidden __udivsi3_i4i
69#endif
70
71
72/* r0 <= r4 / r5 */
73NENTRY(__udivsi3_i4i)
74	tst	r5, r5
75	bt	.L_div_by_zero
76
77	mov	r4, r1		! cannot clobber r4 in this version
78	mov	#0, r0
79	div0u
80#define DIVSTEP	rotcl r1; div1 r5, r0
81	/* repeat 32 times */
82	DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
83	DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
84	DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
85	DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP; DIVSTEP;
86#undef DIVSTEP
87	rotcl	r1
88
89	rts
90	 mov	r1, r0
91
92.L_div_by_zero:
93	rts
94	 mov	#0, r0
95