xref: /freebsd/lib/msun/i387/s_remquol.S (revision 60d717baf2144cf344ec9b47d715ce837b5d46d4)
1 /*-
2  * Copyright (c) 2005-2008 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 ENTRY(remquol)
33 	fldt	16(%esp)
34 	fldt	4(%esp)
35 1:	fprem1
36 	fstsw	%ax
37 	sahf
38 	jp	1b
39 	fstp	%st(1)
40 /* Extract the three low-order bits of the quotient from C0,C3,C1. */
41 	shrl	$6,%eax
42 	movl	%eax,%ecx
43 	andl	$0x108,%eax
44 	rorl	$7,%eax
45 	orl	%eax,%ecx
46 	roll	$4,%eax
47 	orl	%ecx,%eax
48 	andl	$7,%eax
49 /* Negate the quotient bits if x*y<0.  Avoid using an unpredictable branch. */
50 	movl	24(%esp),%ecx
51 	xorl	12(%esp),%ecx
52 	movsx	%cx,%ecx
53 	sarl	$16,%ecx
54 	sarl	$16,%ecx
55 	xorl	%ecx,%eax
56 	andl	$1,%ecx
57 	addl	%ecx,%eax
58 /* Store the quotient and return. */
59 	movl	28(%esp),%ecx
60 	movl	%eax,(%ecx)
61 	ret
62 END(remquol)
63 
64 	.section .note.GNU-stack,"",%progbits
65