xref: /freebsd/lib/msun/i387/s_remquof.S (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1/*-
2 * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27/*
28 * Based on public-domain remainder routine by J.T. Conklin <jtc@NetBSD.org>.
29 */
30
31#include <machine/asm.h>
32__FBSDID("$FreeBSD$");
33
34ENTRY(remquof)
35	flds	8(%esp)
36	flds	4(%esp)
371:	fprem1
38	fstsw	%ax
39	sahf
40	jp	1b
41	fstp	%st(1)
42/* Extract the three low-order bits of the quotient from C0,C3,C1. */
43	shrl	$6,%eax
44	movl	%eax,%ecx
45	andl	$0x108,%eax
46	rorl	$7,%eax
47	orl	%eax,%ecx
48	roll	$4,%eax
49	orl	%ecx,%eax
50	andl	$7,%eax
51/* Negate the quotient bits if x*y<0.  Avoid using an unpredictable branch. */
52	movl	8(%esp),%ecx
53	xorl	4(%esp),%ecx
54	sarl	$16,%ecx
55	sarl	$16,%ecx
56	xorl	%ecx,%eax
57	andl	$1,%ecx
58	addl	%ecx,%eax
59/* Store the quotient and return. */
60	movl	12(%esp),%ecx
61	movl	%eax,(%ecx)
62	ret
63END(remquof)
64
65	.section .note.GNU-stack,"",%progbits
66