forked from OSchip/llvm-project
56 lines
1.2 KiB
C
56 lines
1.2 KiB
C
/* This file is distributed under the University of Illinois Open Source
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* License. See LICENSE.TXT for details.
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*/
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/* long double __gcc_qdiv(long double x, long double y);
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* This file implements the PowerPC 128-bit double-double division operation.
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* This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
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*/
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#include "DD.h"
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long double __gcc_qdiv(long double a, long double b)
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{
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static const uint32_t infinityHi = UINT32_C(0x7ff00000);
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DD dst = { .ld = a }, src = { .ld = b };
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register double x = dst.s.hi, x1 = dst.s.lo,
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y = src.s.hi, y1 = src.s.lo;
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double yHi, yLo, qHi, qLo;
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double yq, tmp, q;
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q = x / y;
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/* Detect special cases */
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if (q == 0.0) {
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dst.s.hi = q;
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dst.s.lo = 0.0;
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return dst.ld;
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}
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const doublebits qBits = { .d = q };
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if (((uint32_t)(qBits.x >> 32) & infinityHi) == infinityHi) {
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dst.s.hi = q;
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dst.s.lo = 0.0;
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return dst.ld;
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}
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yHi = high26bits(y);
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qHi = high26bits(q);
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yq = y * q;
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yLo = y - yHi;
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qLo = q - qHi;
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tmp = LOWORDER(yq, yHi, yLo, qHi, qLo);
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tmp = (x - yq) - tmp;
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tmp = ((tmp + x1) - y1 * q) / y;
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x = q + tmp;
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dst.s.lo = (q - x) + tmp;
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dst.s.hi = x;
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return dst.ld;
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}
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