diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/s_fmal.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-128ibm/s_fmal.c | 257 |
1 files changed, 0 insertions, 257 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_fmal.c b/sysdeps/ieee754/ldbl-128ibm/s_fmal.c deleted file mode 100644 index 9098e79df9..0000000000 --- a/sysdeps/ieee754/ldbl-128ibm/s_fmal.c +++ /dev/null @@ -1,257 +0,0 @@ -/* Compute x * y + z as ternary operation. - Copyright (C) 2011-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by David Flaherty <flaherty@linux.vnet.ibm.com>. - - The GNU C Library 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. - - The GNU C Library 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 the GNU C Library; if not, see - <http://www.gnu.org/licenses/>. */ - -#include <fenv.h> -#include <float.h> -#include <math.h> -#include <math_private.h> -#include <math_ldbl_opt.h> -#include <mul_split.h> -#include <stdlib.h> - -/* Calculate X + Y exactly and store the result in *HI + *LO. It is - given that |X| >= |Y| and the values are small enough that no - overflow occurs. */ - -static void -add_split (double *hi, double *lo, double x, double y) -{ - /* Apply Dekker's algorithm. */ - *hi = x + y; - *lo = (x - *hi) + y; -} - -/* Value with extended range, used in intermediate computations. */ -typedef struct -{ - /* Value in [0.5, 1), as from frexp, or 0. */ - double val; - /* Exponent of power of 2 it is multiplied by, or 0 for zero. */ - int exp; -} ext_val; - -/* Store D as an ext_val value. */ - -static void -store_ext_val (ext_val *v, double d) -{ - v->val = __frexp (d, &v->exp); -} - -/* Store X * Y as ext_val values *V0 and *V1. */ - -static void -mul_ext_val (ext_val *v0, ext_val *v1, double x, double y) -{ - int xexp, yexp; - x = __frexp (x, &xexp); - y = __frexp (y, &yexp); - double hi, lo; - mul_split (&hi, &lo, x, y); - store_ext_val (v0, hi); - if (hi != 0) - v0->exp += xexp + yexp; - store_ext_val (v1, lo); - if (lo != 0) - v1->exp += xexp + yexp; -} - -/* Compare absolute values of ext_val values pointed to by P and Q for - qsort. */ - -static int -compare (const void *p, const void *q) -{ - const ext_val *pe = p; - const ext_val *qe = q; - if (pe->val == 0) - return qe->val == 0 ? 0 : -1; - else if (qe->val == 0) - return 1; - else if (pe->exp < qe->exp) - return -1; - else if (pe->exp > qe->exp) - return 1; - else - { - double pd = fabs (pe->val); - double qd = fabs (qe->val); - if (pd < qd) - return -1; - else if (pd == qd) - return 0; - else - return 1; - } -} - -/* Calculate *X + *Y exactly, storing the high part in *X (rounded to - nearest) and the low part in *Y. It is given that |X| >= |Y|. */ - -static void -add_split_ext (ext_val *x, ext_val *y) -{ - int xexp = x->exp, yexp = y->exp; - if (y->val == 0 || xexp - yexp > 53) - return; - double hi = x->val; - double lo = __scalbn (y->val, yexp - xexp); - add_split (&hi, &lo, hi, lo); - store_ext_val (x, hi); - if (hi != 0) - x->exp += xexp; - store_ext_val (y, lo); - if (lo != 0) - y->exp += xexp; -} - -long double -__fmal (long double x, long double y, long double z) -{ - double xhi, xlo, yhi, ylo, zhi, zlo; - int64_t hx, hy, hz; - int xexp, yexp, zexp; - double scale_val; - int scale_exp; - ldbl_unpack (x, &xhi, &xlo); - EXTRACT_WORDS64 (hx, xhi); - xexp = (hx & 0x7ff0000000000000LL) >> 52; - ldbl_unpack (y, &yhi, &ylo); - EXTRACT_WORDS64 (hy, yhi); - yexp = (hy & 0x7ff0000000000000LL) >> 52; - ldbl_unpack (z, &zhi, &zlo); - EXTRACT_WORDS64 (hz, zhi); - zexp = (hz & 0x7ff0000000000000LL) >> 52; - - /* If z is Inf or NaN, but x and y are finite, avoid any exceptions - from computing x * y. */ - if (zexp == 0x7ff && xexp != 0x7ff && yexp != 0x7ff) - return (z + x) + y; - - /* If z is zero and x are y are nonzero, compute the result as x * y - to avoid the wrong sign of a zero result if x * y underflows to - 0. */ - if (z == 0 && x != 0 && y != 0) - return x * y; - - /* If x or y or z is Inf/NaN, or if x * y is zero, compute as x * y - + z. */ - if (xexp == 0x7ff || yexp == 0x7ff || zexp == 0x7ff - || x == 0 || y == 0) - return (x * y) + z; - - { - SET_RESTORE_ROUND (FE_TONEAREST); - - ext_val vals[10]; - store_ext_val (&vals[0], zhi); - store_ext_val (&vals[1], zlo); - mul_ext_val (&vals[2], &vals[3], xhi, yhi); - mul_ext_val (&vals[4], &vals[5], xhi, ylo); - mul_ext_val (&vals[6], &vals[7], xlo, yhi); - mul_ext_val (&vals[8], &vals[9], xlo, ylo); - qsort (vals, 10, sizeof (ext_val), compare); - /* Add up the values so that each element of VALS has absolute - value at most equal to the last set bit of the next nonzero - element. */ - for (size_t i = 0; i <= 8; i++) - { - add_split_ext (&vals[i + 1], &vals[i]); - qsort (vals + i + 1, 9 - i, sizeof (ext_val), compare); - } - /* Add up the values in the other direction, so that each element - of VALS has absolute value less than 5ulp of the next - value. */ - size_t dstpos = 9; - for (size_t i = 1; i <= 9; i++) - { - if (vals[dstpos].val == 0) - { - vals[dstpos] = vals[9 - i]; - vals[9 - i].val = 0; - vals[9 - i].exp = 0; - } - else - { - add_split_ext (&vals[dstpos], &vals[9 - i]); - if (vals[9 - i].val != 0) - { - if (9 - i < dstpos - 1) - { - vals[dstpos - 1] = vals[9 - i]; - vals[9 - i].val = 0; - vals[9 - i].exp = 0; - } - dstpos--; - } - } - } - /* If the result is an exact zero, it results from adding two - values with opposite signs; recompute in the original rounding - mode. */ - if (vals[9].val == 0) - goto zero_out; - /* Adding the top three values will now give a result as accurate - as the underlying long double arithmetic. */ - add_split_ext (&vals[9], &vals[8]); - if (compare (&vals[8], &vals[7]) < 0) - { - ext_val tmp = vals[7]; - vals[7] = vals[8]; - vals[8] = tmp; - } - add_split_ext (&vals[8], &vals[7]); - add_split_ext (&vals[9], &vals[8]); - if (vals[9].exp > DBL_MAX_EXP || vals[9].exp < DBL_MIN_EXP) - { - /* Overflow or underflow, with the result depending on the - original rounding mode, but not on the low part computed - here. */ - scale_val = vals[9].val; - scale_exp = vals[9].exp; - goto scale_out; - } - double hi = __scalbn (vals[9].val, vals[9].exp); - double lo = __scalbn (vals[8].val, vals[8].exp); - /* It is possible that the low part became subnormal and was - rounded so that the result is no longer canonical. */ - ldbl_canonicalize (&hi, &lo); - long double ret = ldbl_pack (hi, lo); - math_check_force_underflow (ret); - return ret; - } - - scale_out: - scale_val = math_opt_barrier (scale_val); - scale_val = __scalbn (scale_val, scale_exp); - if (fabs (scale_val) == DBL_MAX) - return __copysignl (LDBL_MAX, scale_val); - math_check_force_underflow (scale_val); - return scale_val; - - zero_out:; - double zero = 0.0; - zero = math_opt_barrier (zero); - return zero - zero; -} -#if IS_IN (libm) -long_double_symbol (libm, __fmal, fmal); -#else -long_double_symbol (libc, __fmal, fmal); -#endif |