fabs.c   [plain text]


/*
 * Copyright (c) 2002 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*******************************************************************************
*                                                                              *
*     File:  fabs.c                                                            *
*                                                                              *
*     Contains: C99 fabs				      		       *
*                                                                              *
*     Copyright  2001 Apple Computer, Inc.  All rights reserved.              *
*                                                                              *
*     Written by Stephen C. Peters, started in November 2001.                  *
*                                                                              *
*     A MathLib v5 file.                                                       *
*                                                                              *
*     Change History (most recent first):                                      *
*                                                                              *
*     21 Nov 01   scp   First created.                                         *
*                                                                              *
*     W A R N I N G:                                                           *
*     These routines require a 64-bit double precision IEEE-754 model.         *
*     They are written for PowerPC only and are expecting the compiler         *
*     to generate the correct sequence of multiply-add fused instructions.     *
*                                                                              *
*     These routines are not intended for 32-bit Intel architectures.          *
*                                                                              *
*     A version of gcc higher than 932 is required.                            *
*                                                                              *
*     GCC compiler options:                                                    *
*           optimization level 3 (-O3)                                         *
*           -fschedule-insns -finline-functions -funroll-all-loops             *
*                                                                              *
*******************************************************************************/

#ifdef      __APPLE_CC__
#if         __APPLE_CC__ > 930

/*
 * fabs(x) returns the absolute value of x.
 */

/* gcc 2.95 inlines fabs() and fabsf() of its own accord. But in case we ever get here ... */ 

#define __FABS(x) \
({ \
    double __value, __arg = (x); \
    asm volatile ("fabs %0,%1" : "=f" (__value): "f" (__arg)); \
    __value; \
})  

#define __FABSF(x) \
({ \
    float __value, __arg = (x); \
    asm volatile ("fabs %0,%1" : "=f" (__value): "f" (__arg)); \
    __value; \
})  

double fabs(double x)
{
    return __FABS(x);
}

float fabsf(float x)
{
    return __FABSF(x);
}

#else       /* __APPLE_CC__ version */
#error Version gcc-932 or higher required.  Compilation terminated.
#endif      /* __APPLE_CC__ version */
#endif      /* __APPLE_CC__ */