diff options
Diffstat (limited to 'lib/builtins/ppc/gcc_qsub.c')
| -rw-r--r-- | lib/builtins/ppc/gcc_qsub.c | 140 |
1 files changed, 69 insertions, 71 deletions
diff --git a/lib/builtins/ppc/gcc_qsub.c b/lib/builtins/ppc/gcc_qsub.c index c092e24db..ac08120be 100644 --- a/lib/builtins/ppc/gcc_qsub.c +++ b/lib/builtins/ppc/gcc_qsub.c @@ -1,76 +1,74 @@ -/* This file is distributed under the University of Illinois Open Source - * License. See LICENSE.TXT for details. - */ +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception -/* long double __gcc_qsub(long double x, long double y); - * This file implements the PowerPC 128-bit double-double add operation. - * This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!) - */ +// long double __gcc_qsub(long double x, long double y); +// This file implements the PowerPC 128-bit double-double add operation. +// This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!) #include "DD.h" -long double __gcc_qsub(long double x, long double y) -{ - static const uint32_t infinityHi = UINT32_C(0x7ff00000); - - DD dst = { .ld = x }, src = { .ld = y }; - - register double A = dst.s.hi, a = dst.s.lo, - B = -src.s.hi, b = -src.s.lo; - - /* If both operands are zero: */ - if ((A == 0.0) && (B == 0.0)) { - dst.s.hi = A + B; - dst.s.lo = 0.0; - return dst.ld; - } - - /* If either operand is NaN or infinity: */ - const doublebits abits = { .d = A }; - const doublebits bbits = { .d = B }; - if ((((uint32_t)(abits.x >> 32) & infinityHi) == infinityHi) || - (((uint32_t)(bbits.x >> 32) & infinityHi) == infinityHi)) { - dst.s.hi = A + B; - dst.s.lo = 0.0; - return dst.ld; - } - - /* If the computation overflows: */ - /* This may be playing things a little bit fast and loose, but it will do for a start. */ - const double testForOverflow = A + (B + (a + b)); - const doublebits testbits = { .d = testForOverflow }; - if (((uint32_t)(testbits.x >> 32) & infinityHi) == infinityHi) { - dst.s.hi = testForOverflow; - dst.s.lo = 0.0; - return dst.ld; - } - - double H, h; - double T, t; - double W, w; - double Y; - - H = B + (A - (A + B)); - T = b + (a - (a + b)); - h = A + (B - (A + B)); - t = a + (b - (a + b)); - - if (local_fabs(A) <= local_fabs(B)) - w = (a + b) + h; - else - w = (a + b) + H; - - W = (A + B) + w; - Y = (A + B) - W; - Y += w; - - if (local_fabs(a) <= local_fabs(b)) - w = t + Y; - else - w = T + Y; - - dst.s.hi = Y = W + w; - dst.s.lo = (W - Y) + w; - - return dst.ld; +long double __gcc_qsub(long double x, long double y) { + static const uint32_t infinityHi = UINT32_C(0x7ff00000); + + DD dst = {.ld = x}, src = {.ld = y}; + + register double A = dst.s.hi, a = dst.s.lo, B = -src.s.hi, b = -src.s.lo; + + // If both operands are zero: + if ((A == 0.0) && (B == 0.0)) { + dst.s.hi = A + B; + dst.s.lo = 0.0; + return dst.ld; + } + + // If either operand is NaN or infinity: + const doublebits abits = {.d = A}; + const doublebits bbits = {.d = B}; + if ((((uint32_t)(abits.x >> 32) & infinityHi) == infinityHi) || + (((uint32_t)(bbits.x >> 32) & infinityHi) == infinityHi)) { + dst.s.hi = A + B; + dst.s.lo = 0.0; + return dst.ld; + } + + // If the computation overflows: + // This may be playing things a little bit fast and loose, but it will do for + // a start. + const double testForOverflow = A + (B + (a + b)); + const doublebits testbits = {.d = testForOverflow}; + if (((uint32_t)(testbits.x >> 32) & infinityHi) == infinityHi) { + dst.s.hi = testForOverflow; + dst.s.lo = 0.0; + return dst.ld; + } + + double H, h; + double T, t; + double W, w; + double Y; + + H = B + (A - (A + B)); + T = b + (a - (a + b)); + h = A + (B - (A + B)); + t = a + (b - (a + b)); + + if (local_fabs(A) <= local_fabs(B)) + w = (a + b) + h; + else + w = (a + b) + H; + + W = (A + B) + w; + Y = (A + B) - W; + Y += w; + + if (local_fabs(a) <= local_fabs(b)) + w = t + Y; + else + w = T + Y; + + dst.s.hi = Y = W + w; + dst.s.lo = (W - Y) + w; + + return dst.ld; } |