da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/***********************************************************************
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* This software is part of the ast package *
3e14f97f673e8a630f076077de35afdd43dc1587Roger A. Faulkner* Copyright (c) 1985-2010 AT&T Intellectual Property *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* and is licensed under the *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Common Public License, Version 1.0 *
7c2fbfb345896881c631598ee3852ce9ce33fb07April Chin* by AT&T Intellectual Property *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* A copy of the License is available at *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* http://www.opensource.org/licenses/cpl1.0.txt *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Information and Software Systems Research *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* AT&T Research *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Florham Park NJ *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Glenn Fowler <gsf@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* David Korn <dgk@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Phong Vo <kpv@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin***********************************************************************/
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#pragma prototyped
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * frexpl/ldexpl implementation
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include <ast.h>
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include "FEATURE/float"
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#if _lib_frexpl && _lib_ldexpl
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinNoN(frexpl)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#ifndef LDBL_MAX_EXP
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#define LDBL_MAX_EXP DBL_MAX_EXP
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#if defined(_ast_fltmax_exp_index) && defined(_ast_fltmax_exp_shift)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#define INIT() _ast_fltmax_exp_t _pow_
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#define pow2(i) (_pow_.f=1,_pow_.e[_ast_fltmax_exp_index]+=((i)<<_ast_fltmax_exp_shift),_pow_.f)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinstatic _ast_fltmax_t pow2tab[LDBL_MAX_EXP + 1];
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinstatic int
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chininit(void)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin register int x;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin _ast_fltmax_t g;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin g = 1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin for (x = 0; x < elementsof(pow2tab); x++)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin pow2tab[x] = g;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin g *= 2;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return 0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#define INIT() (pow2tab[0]?0:init())
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#define pow2(i) (pow2tab[i])
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#if !_lib_frexpl
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#undef frexpl
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinextern _ast_fltmax_t
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinfrexpl(_ast_fltmax_t f, int* p)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin register int k;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin register int x;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin _ast_fltmax_t g;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin INIT();
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * normalize
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin x = k = LDBL_MAX_EXP / 2;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if (f < 1)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin g = 1.0L / f;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin for (;;)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin k = (k + 1) / 2;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if (g < pow2(x))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin x -= k;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if (k == 1 && g < pow2(x+1))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin break;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin x += k;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if (g == pow2(x))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin x--;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin x = -x;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if (f > 1)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin for (;;)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin k = (k + 1) / 2;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if (f > pow2(x))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin x += k;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if (k == 1 && f > pow2(x-1))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin break;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin x -= k;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if (f == pow2(x))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin x++;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin x = 1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin *p = x;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * shift
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin x = -x;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if (x < 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f /= pow2(-x);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if (x < LDBL_MAX_EXP)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f *= pow2(x);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f = (f * pow2(LDBL_MAX_EXP - 1)) * pow2(x - (LDBL_MAX_EXP - 1));
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return f;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#if !_lib_ldexpl
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#undef ldexpl
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinextern _ast_fltmax_t
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinldexpl(_ast_fltmax_t f, register int x)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin INIT();
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if (x < 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f /= pow2(-x);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if (x < LDBL_MAX_EXP)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f *= pow2(x);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f = (f * pow2(LDBL_MAX_EXP - 1)) * pow2(x - (LDBL_MAX_EXP - 1));
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return f;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif