freebsd-dev/lib/libc/i386/gen/modf.S
Peter Wemm f1703dfbaa Add support to enable libc to be compiled in ELF format. (#ifdef __ELF__)
In a nutshell, this macroizes the local/global symbol scoping rules
that are different in a.out and ELF.  It also makes the i386 assembler
stubs conform to i386 PIC calling conventions - the a.out ld.so didn't
object, but the ELF one needs it as it implements PIC jumps via PLT's as
well as calls.  The a.out rtld only worked because it was accidently
snooping the grandparent calling function's return address off the stack..

This also affects the libc_r code a little, because of cpp macro nesting.
1996-05-05 07:56:21 +00:00

80 lines
2.7 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.
*
* $Id: modf.S,v 1.2 1995/01/23 01:27:05 davidg Exp $
*/
#if defined(LIBC_RCS) && !defined(lint)
.text
.asciz "$Id: modf.S,v 1.2 1995/01/23 01:27:05 davidg Exp $"
#endif /* LIBC_RCS and not lint */
/*
* 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. */
#include "DEFS.h"
ENTRY(modf)
pushl %ebp
movl %esp,%ebp
subl $16,%esp
fnstcw -12(%ebp)
movw -12(%ebp),%dx
orw $3072,%dx
movw %dx,-16(%ebp)
fldcw -16(%ebp)
fldl 8(%ebp)
frndint
fstpl -8(%ebp)
fldcw -12(%ebp)
movl 16(%ebp),%eax
movl -8(%ebp),%edx
movl -4(%ebp),%ecx
movl %edx,(%eax)
movl %ecx,4(%eax)
fldl 8(%ebp)
fsubl -8(%ebp)
jmp L1
L1:
leave
ret