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 fldl 12(%esp) 36 fldl 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 16(%esp),%ecx 53 xorl 8(%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 20(%esp),%ecx 61 movl %eax,(%ecx) 62 ret 63