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Diffstat (limited to 'sysdeps/ieee754/dbl-64/halfulp.c')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/halfulp.c | 152 |
1 files changed, 0 insertions, 152 deletions
diff --git a/sysdeps/ieee754/dbl-64/halfulp.c b/sysdeps/ieee754/dbl-64/halfulp.c deleted file mode 100644 index 0768d8641f..0000000000 --- a/sysdeps/ieee754/dbl-64/halfulp.c +++ /dev/null @@ -1,152 +0,0 @@ -/* - * IBM Accurate Mathematical Library - * written by International Business Machines Corp. - * Copyright (C) 2001-2018 Free Software Foundation, Inc. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU Lesser General Public License as published by - * the Free Software Foundation; either version 2.1 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public License - * along with this program; if not, see <http://www.gnu.org/licenses/>. - */ -/************************************************************************/ -/* */ -/* MODULE_NAME:halfulp.c */ -/* */ -/* FUNCTIONS:halfulp */ -/* FILES NEEDED: mydefs.h dla.h endian.h */ -/* uroot.c */ -/* */ -/*Routine halfulp(double x, double y) computes x^y where result does */ -/*not need rounding. If the result is closer to 0 than can be */ -/*represented it returns 0. */ -/* In the following cases the function does not compute anything */ -/*and returns a negative number: */ -/*1. if the result needs rounding, */ -/*2. if y is outside the interval [0, 2^20-1], */ -/*3. if x can be represented by x=2**n for some integer n. */ -/************************************************************************/ - -#include "endian.h" -#include "mydefs.h" -#include <dla.h> -#include <math_private.h> - -#ifndef SECTION -# define SECTION -#endif - -static const int4 tab54[32] = { - 262143, 11585, 1782, 511, 210, 107, 63, 42, - 30, 22, 17, 14, 12, 10, 9, 7, - 7, 6, 5, 5, 5, 4, 4, 4, - 3, 3, 3, 3, 3, 3, 3, 3 -}; - - -double -SECTION -__halfulp (double x, double y) -{ - mynumber v; - double z, u, uu; -#ifndef DLA_FMS - double j1, j2, j3, j4, j5; -#endif - int4 k, l, m, n; - if (y <= 0) /*if power is negative or zero */ - { - v.x = y; - if (v.i[LOW_HALF] != 0) - return -10.0; - v.x = x; - if (v.i[LOW_HALF] != 0) - return -10.0; - if ((v.i[HIGH_HALF] & 0x000fffff) != 0) - return -10; /* if x =2 ^ n */ - k = ((v.i[HIGH_HALF] & 0x7fffffff) >> 20) - 1023; /* find this n */ - z = (double) k; - return (z * y == -1075.0) ? 0 : -10.0; - } - /* if y > 0 */ - v.x = y; - if (v.i[LOW_HALF] != 0) - return -10.0; - - v.x = x; - /* case where x = 2**n for some integer n */ - if (((v.i[HIGH_HALF] & 0x000fffff) | v.i[LOW_HALF]) == 0) - { - k = (v.i[HIGH_HALF] >> 20) - 1023; - return (((double) k) * y == -1075.0) ? 0 : -10.0; - } - - v.x = y; - k = v.i[HIGH_HALF]; - m = k << 12; - l = 0; - while (m) - { - m = m << 1; l++; - } - n = (k & 0x000fffff) | 0x00100000; - n = n >> (20 - l); /* n is the odd integer of y */ - k = ((k >> 20) - 1023) - l; /* y = n*2**k */ - if (k > 5) - return -10.0; - if (k > 0) - for (; k > 0; k--) - n *= 2; - if (n > 34) - return -10.0; - k = -k; - if (k > 5) - return -10.0; - - /* now treat x */ - while (k > 0) - { - z = __ieee754_sqrt (x); - EMULV (z, z, u, uu, j1, j2, j3, j4, j5); - if (((u - x) + uu) != 0) - break; - x = z; - k--; - } - if (k) - return -10.0; - - /* it is impossible that n == 2, so the mantissa of x must be short */ - - v.x = x; - if (v.i[LOW_HALF]) - return -10.0; - k = v.i[HIGH_HALF]; - m = k << 12; - l = 0; - while (m) - { - m = m << 1; l++; - } - m = (k & 0x000fffff) | 0x00100000; - m = m >> (20 - l); /* m is the odd integer of x */ - - /* now check whether the length of m**n is at most 54 bits */ - - if (m > tab54[n - 3]) - return -10.0; - - /* yes, it is - now compute x**n by simple multiplications */ - - u = x; - for (k = 1; k < n; k++) - u = u * x; - return u; -} |