/* * 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 hypot.c, * * Function hypot(x,y), * * Implementation of sqrt(x^2+y^2) for the PowerPC. * * * * Copyright © 1991 Apple Computer, Inc. All rights reserved. * * * * Written by Ali Sazegari, started on November 1991, * * * * based on math.h, library code for Macintoshes with a 68881/68882 * * by Jim Thomas. * * * * W A R N I N G: This routine expects a 64 bit double model. * * * * December 03 1992: first rs6000 port. * * January 05 1993: added the environmental controls. * * July 14 1993: added #pragma fenv_access. changed feholdexcept * * to the internal routine _feprocentry. * * September22 1993: conforming to nceg-fpce specification for ±° values. * * September19 1994: revamp of the algorithm for performance. * * * *******************************************************************************/ #ifdef __APPLE_CC__ #if __APPLE_CC__ > 930 #include "math.h" #include "fenv.h" #include "fp_private.h" #include "fenv_private.h" /******************************************************************************* * Functions needed for the computation. * *******************************************************************************/ /* the following fp.h functions are used: */ /* fabs and sqrt; */ /* the following environmental functions are used: */ /* feclearexcept, _feprocentry and feupdateenv. */ #pragma fenv_access on static const hexdouble Huge = HEXDOUBLE(0x7FF00000, 0x00000000); #ifdef notdef { register double temp; hexdouble OldEnvironment, CurrentEnvironment; /******************************************************************************* * If argument is SNaN then a QNaN has to be returned and the invalid * * flag signaled. * *******************************************************************************/ if ( ( x == Huge.d ) || ( y == Huge.d ) || ( x == - Huge.d ) || ( y == - Huge.d ) ) { return Huge.d; } if ( ( x != x ) || ( y != y ) ) { x = __FABS ( x + y ); return x; } FEGETENVD( OldEnvironment.d ); // save environment, set default FESETENVD( 0.0 ); if ( ( x = __FABS ( x ) ) > ( y = __FABS ( y ) ) ) /* make sure |x| <= |y| */ { temp = x; x = y; y = temp; } if ( ( y != 0.0 ) && ( y != INFINITY ) ) { temp = x / y; temp = sqrt ( 1.0 + temp * temp ); FEGETENVD( CurrentEnvironment.d ); CurrentEnvironment.i.lo &= ~FE_UNDERFLOW; FESETENVD( CurrentEnvironment.d ); y = y * temp; } FEGETENVD( CurrentEnvironment.d ); OldEnvironment.i.lo |= CurrentEnvironment.i.lo; FESETENVD( OldEnvironment.d ); // restore caller's environment return y; } #else static const hexdouble NegHuge = HEXDOUBLE(0xFFF00000, 0x00000000); double hypot ( double x, double y ) { register double temp; hexdouble OldEnvironment, CurrentEnvironment; register double FPR_env, FPR_z, FPR_one, FPR_inf, FPR_Minf, FPR_absx, FPR_absy, FPR_big, FPR_small; FPR_z = 0.0; FPR_one = 1.0; FPR_inf = Huge.d; FPR_Minf = NegHuge.d; FPR_absx = __FABS( x ); FPR_absy = __FABS( y ); /******************************************************************************* * If argument is SNaN then a QNaN has to be returned and the invalid * * flag signaled. * *******************************************************************************/ if ( ( x == FPR_inf ) || ( y == FPR_inf ) || ( x == FPR_Minf ) || ( y == FPR_Minf ) ) return FPR_inf; if ( ( x != x ) || ( y != y ) ) { x = __FABS ( x + y ); return x; } if ( FPR_absx > FPR_absy ) { FPR_big = FPR_absx; FPR_small = FPR_absy; } else { FPR_big = FPR_absy; FPR_small = FPR_absx; } // Now +0.0 <= FPR_small <= FPR_big < INFINITY if ( FPR_small == FPR_z ) return FPR_big; FEGETENVD( FPR_env ); // save environment, set default FESETENVD( FPR_z ); temp = FPR_small / FPR_big; OldEnvironment.d = FPR_env; temp = sqrt ( FPR_one + temp * temp ); FEGETENVD( CurrentEnvironment.d ); CurrentEnvironment.i.lo &= ~FE_UNDERFLOW; // Clear any inconsequential underflow FESETENVD( CurrentEnvironment.d ); temp = FPR_big * temp; // Might raise UNDERFLOW or OVERFLOW FEGETENVD( CurrentEnvironment.d ); OldEnvironment.i.lo |= CurrentEnvironment.i.lo; // Pick up any UF or OF FESETENVD( OldEnvironment.d ); // restore caller's environment return temp; } #endif #else /* __APPLE_CC__ version */ #error Version gcc-932 or higher required. Compilation terminated. #endif /* __APPLE_CC__ version */ #endif /* __APPLE_CC__ */