xref: /freebsd/lib/msun/amd64/s_remquo.S (revision 57718be8fa0bd5edc11ab9a72e68cc71982939a6)
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(remquo)
35	movsd	%xmm0,-8(%rsp)
36	movsd	%xmm1,-16(%rsp)
37	fldl	-16(%rsp)
38	fldl	-8(%rsp)
391:	fprem1
40	fstsw	%ax
41	btw	$10,%ax
42	jc	1b
43	fstp	%st(1)
44/* Extract the three low-order bits of the quotient from C0,C3,C1. */
45	shrl	$6,%eax
46	movl	%eax,%ecx
47	andl	$0x108,%eax
48	rorl	$7,%eax
49	orl	%eax,%ecx
50	roll	$4,%eax
51	orl	%ecx,%eax
52	andl	$7,%eax
53/* Negate the quotient bits if x*y<0.  Avoid using an unpredictable branch. */
54	movl	-12(%rsp),%ecx
55	xorl	-4(%rsp),%ecx
56	sarl	$16,%ecx
57	sarl	$16,%ecx
58	xorl	%ecx,%eax
59	andl	$1,%ecx
60	addl	%ecx,%eax
61/* Store the quotient and return. */
62	movl	%eax,(%rdi)
63	fstpl	-8(%rsp)
64	movsd	-8(%rsp),%xmm0
65	ret
66END(remquo)
67
68	.section .note.GNU-stack,"",%progbits
69