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https://github.com/86Box/86Box.git
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188 lines
7.4 KiB
C++
188 lines
7.4 KiB
C++
/*============================================================================
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This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
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Package, Release 3e, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014 The Regents of the University of California.
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice,
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this list of conditions, and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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3. Neither the name of the University nor the names of its contributors may
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be used to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
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DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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=============================================================================*/
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#include <stdbool.h>
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#include <stdint.h>
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#include "internals.h"
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#include "primitives.h"
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#include "specialize.h"
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#include "softfloat.h"
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float128_t f128_div(float128_t a, float128_t b, struct softfloat_status_t *status)
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{
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uint64_t uiA64, uiA0;
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bool signA;
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int32_t expA;
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struct uint128 sigA;
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uint64_t uiB64, uiB0;
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bool signB;
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int32_t expB;
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struct uint128 sigB;
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bool signZ;
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struct exp32_sig128 normExpSig;
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int32_t expZ;
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struct uint128 rem;
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uint32_t recip32;
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int ix;
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uint64_t q64;
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uint32_t q;
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struct uint128 term;
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uint32_t qs[3];
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uint64_t sigZExtra;
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struct uint128 sigZ, uiZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uiA64 = a.v64;
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uiA0 = a.v0;
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signA = signF128UI64(uiA64);
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expA = expF128UI64(uiA64);
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sigA.v64 = fracF128UI64(uiA64);
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sigA.v0 = uiA0;
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uiB64 = b.v64;
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uiB0 = b.v0;
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signB = signF128UI64(uiB64);
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expB = expF128UI64(uiB64);
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sigB.v64 = fracF128UI64(uiB64);
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sigB.v0 = uiB0;
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signZ = signA ^ signB;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if (expA == 0x7FFF) {
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if (sigA.v64 | sigA.v0) goto propagateNaN;
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if (expB == 0x7FFF) {
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if (sigB.v64 | sigB.v0) goto propagateNaN;
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goto invalid;
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}
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goto infinity;
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}
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if (expB == 0x7FFF) {
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if (sigB.v64 | sigB.v0) goto propagateNaN;
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goto zero;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if (! expB) {
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if (! (sigB.v64 | sigB.v0)) {
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if (! (expA | sigA.v64 | sigA.v0)) goto invalid;
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softfloat_raiseFlags(status, softfloat_flag_infinite);
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goto infinity;
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}
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softfloat_raiseFlags(status, softfloat_flag_denormal);
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normExpSig = softfloat_normSubnormalF128Sig(sigB.v64, sigB.v0);
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expB = normExpSig.exp;
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sigB = normExpSig.sig;
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}
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if (! expA) {
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if (! (sigA.v64 | sigA.v0)) goto zero;
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softfloat_raiseFlags(status, softfloat_flag_denormal);
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normExpSig = softfloat_normSubnormalF128Sig(sigA.v64, sigA.v0);
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expA = normExpSig.exp;
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sigA = normExpSig.sig;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expZ = expA - expB + 0x3FFE;
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sigA.v64 |= UINT64_C(0x0001000000000000);
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sigB.v64 |= UINT64_C(0x0001000000000000);
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rem = sigA;
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if (softfloat_lt128(sigA.v64, sigA.v0, sigB.v64, sigB.v0)) {
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--expZ;
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rem = softfloat_add128(sigA.v64, sigA.v0, sigA.v64, sigA.v0);
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}
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recip32 = softfloat_approxRecip32_1(sigB.v64>>17);
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ix = 3;
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for (;;) {
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q64 = (uint64_t) (uint32_t) (rem.v64>>19) * recip32;
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q = (q64 + 0x80000000)>>32;
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--ix;
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if (ix < 0) break;
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rem = softfloat_shortShiftLeft128(rem.v64, rem.v0, 29);
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term = softfloat_mul128By32(sigB.v64, sigB.v0, q);
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rem = softfloat_sub128(rem.v64, rem.v0, term.v64, term.v0);
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if (rem.v64 & UINT64_C(0x8000000000000000)) {
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--q;
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rem = softfloat_add128(rem.v64, rem.v0, sigB.v64, sigB.v0);
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}
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qs[ix] = q;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if (((q + 1) & 7) < 2) {
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rem = softfloat_shortShiftLeft128(rem.v64, rem.v0, 29);
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term = softfloat_mul128By32(sigB.v64, sigB.v0, q);
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rem = softfloat_sub128(rem.v64, rem.v0, term.v64, term.v0);
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if (rem.v64 & UINT64_C(0x8000000000000000)) {
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--q;
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rem = softfloat_add128(rem.v64, rem.v0, sigB.v64, sigB.v0);
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} else if (softfloat_le128(sigB.v64, sigB.v0, rem.v64, rem.v0)) {
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++q;
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rem = softfloat_sub128(rem.v64, rem.v0, sigB.v64, sigB.v0);
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}
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if (rem.v64 | rem.v0) q |= 1;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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sigZExtra = (uint64_t) ((uint64_t) q<<60);
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term = softfloat_shortShiftLeft128(0, qs[1], 54);
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sigZ = softfloat_add128((uint64_t) qs[2]<<19, ((uint64_t) qs[0]<<25) + (q>>4), term.v64, term.v0);
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return
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softfloat_roundPackToF128(signZ, expZ, sigZ.v64, sigZ.v0, sigZExtra, status);
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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propagateNaN:
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uiZ = softfloat_propagateNaNF128UI(uiA64, uiA0, uiB64, uiB0, status);
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return uiZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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invalid:
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softfloat_raiseFlags(status, softfloat_flag_invalid);
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uiZ.v64 = defaultNaNF128UI64;
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uiZ.v0 = defaultNaNF128UI0;
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return uiZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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infinity:
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uiZ.v64 = packToF128UI64(signZ, 0x7FFF, 0);
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uiZ.v0 = 0;
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return uiZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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zero:
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uiZ.v64 = packToF128UI64(signZ, 0, 0);
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uiZ.v0 = 0;
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return uiZ;
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}
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