1 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 2 // See https://llvm.org/LICENSE.txt for license information. 3 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 4 5 // long double __gcc_qdiv(long double x, long double y); 6 // This file implements the PowerPC 128-bit double-double division operation. 7 // This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!) 8 9 #include "DD.h" 10 11 long double __gcc_qdiv(long double a, long double b) { 12 static const uint32_t infinityHi = UINT32_C(0x7ff00000); 13 DD dst = {.ld = a}, src = {.ld = b}; 14 15 register double x = dst.s.hi, x1 = dst.s.lo, y = src.s.hi, y1 = src.s.lo; 16 17 double yHi, yLo, qHi, qLo; 18 double yq, tmp, q; 19 20 q = x / y; 21 22 // Detect special cases 23 if (q == 0.0) { 24 dst.s.hi = q; 25 dst.s.lo = 0.0; 26 return dst.ld; 27 } 28 29 const doublebits qBits = {.d = q}; 30 if (((uint32_t)(qBits.x >> 32) & infinityHi) == infinityHi) { 31 dst.s.hi = q; 32 dst.s.lo = 0.0; 33 return dst.ld; 34 } 35 36 yHi = high26bits(y); 37 qHi = high26bits(q); 38 39 yq = y * q; 40 yLo = y - yHi; 41 qLo = q - qHi; 42 43 tmp = LOWORDER(yq, yHi, yLo, qHi, qLo); 44 tmp = (x - yq) - tmp; 45 tmp = ((tmp + x1) - y1 * q) / y; 46 x = q + tmp; 47 48 dst.s.lo = (q - x) + tmp; 49 dst.s.hi = x; 50 51 return dst.ld; 52 } 53