freebsd-skq/lib/libc/amd64/gen/modf.S
Peter Wemm dffecce67c Tidy up modf.S and make it actually work. It wasn't extracting
the value out of ST(0) before copying it to %xmm0.  Also remove bogus stack
frame and work in the red zone.
2003-05-08 03:19:37 +00:00

93 lines
2.8 KiB
ArmAsm

/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Sean Eric Fagan.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)modf.s 5.5 (Berkeley) 3/18/91
*/
#include <machine/asm.h>
#if defined(LIBC_SCCS)
RCSID("$NetBSD: modf.S,v 1.5 1997/07/16 14:37:18 christos Exp $")
#endif
__FBSDID("$FreeBSD$");
/*
* modf(value, iptr): return fractional part of value, and stores the
* integral part into iptr (a pointer to double).
*
* Written by Sean Eric Fagan (sef@kithrup.COM)
* Sun Mar 11 20:27:30 PST 1990
*/
/* With CHOP mode on, frndint behaves as TRUNC does. Useful. */
ENTRY(modf)
/*
* Set chop mode.
*/
fnstcw -12(%rsp)
movw -12(%rsp),%dx
orw $3072,%dx
movw %dx,-16(%rsp)
fldcw -16(%rsp)
/*
* Get integral part.
*/
movsd %xmm0,-24(%rsp)
fldl -24(%rsp)
frndint
fstpl -8(%rsp)
/*
* Restore control word.
*/
fldcw -12(%rsp)
/*
* Store integral part.
*/
movsd -8(%rsp),%xmm0
movsd %xmm0,(%rdi)
/*
* Get fractional part and return it.
*/
fldl -24(%rsp)
fsubl -8(%rsp)
fstpl -8(%rsp)
movsd -8(%rsp),%xmm0
ret