/*
* Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* The contents of this file constitute Original Code as defined in and
* are subject to the Apple Public Source License Version 1.1 (the
* "License"). You may not use this file except in compliance with the
* License. Please obtain a copy of the License at
* http://www.apple.com/publicsource and read it before using this file.
*
* This Original Code and all software distributed under the License are
* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
* License for the specific language governing rights and limitations
* under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
/* Copyright (c) 1992,1997 NeXT Software, Inc. All rights reserved.
*
* File: libc/gen/ppc/abs.s
* Author: Derek B Clegg, NeXT Software, Inc.
*
* HISTORY
* 24-Jan-1997 Umesh Vaishampayan (umeshv@NeXT.com)
* Ported to PPC.
* 10-Nov-92 Derek B Clegg (dclegg@next.com)
* Created.
* 13-Jan-93 Derek B Clegg (dclegg@next.com)
* Optimized.
*
* ANSI X3.159-1989:
* int abs(int j) * Description:
* The `abs' function computes the absolute value of an integer `j'.
* If the result cannot be represented, the behavior is undefined.
* Returns:
* The `abs' function returns the absolute value.
*/
#include <architecture/ppc/asm_help.h>
#include <architecture/ppc/pseudo_inst.h>
/* We calculate abs(x) as
* s = x >> 31 * return y ^ s * If x >= 0, then s = 0, so clearly we return x. On the other hand, if
* x < 0, then we may write x as ~z + 1, where z = -x. In this case,
* s = -1, so y = x - 1 = ~z, and hence we return -1 ^ (x - 1) = -1 ^ ~z
* = z = -x.
*/
LEAF(_abs)
srawi a1,a0,31
add a2,a1,a0
xor a0,a2,a1
blr
END(_abs)