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78 lines
1.4 KiB
78 lines
1.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* IEEE754 floating point arithmetic |
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* double precision: common utilities |
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*/ |
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/* |
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* MIPS floating point support |
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* Copyright (C) 1994-2000 Algorithmics Ltd. |
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* Copyright (C) 2017 Imagination Technologies, Ltd. |
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* Author: Aleksandar Markovic <[email protected]> |
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*/ |
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#include "ieee754dp.h" |
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union ieee754dp ieee754dp_rint(union ieee754dp x) |
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{ |
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union ieee754dp ret; |
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u64 residue; |
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int sticky; |
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int round; |
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int odd; |
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COMPXDP; |
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ieee754_clearcx(); |
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EXPLODEXDP; |
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FLUSHXDP; |
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if (xc == IEEE754_CLASS_SNAN) |
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return ieee754dp_nanxcpt(x); |
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if ((xc == IEEE754_CLASS_QNAN) || |
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(xc == IEEE754_CLASS_INF) || |
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(xc == IEEE754_CLASS_ZERO)) |
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return x; |
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if (xe >= DP_FBITS) |
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return x; |
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if (xe < -1) { |
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residue = xm; |
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round = 0; |
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sticky = residue != 0; |
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xm = 0; |
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} else { |
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residue = xm << (64 - DP_FBITS + xe); |
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round = (residue >> 63) != 0; |
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sticky = (residue << 1) != 0; |
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xm >>= DP_FBITS - xe; |
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} |
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odd = (xm & 0x1) != 0x0; |
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switch (ieee754_csr.rm) { |
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case FPU_CSR_RN: /* toward nearest */ |
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if (round && (sticky || odd)) |
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xm++; |
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break; |
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case FPU_CSR_RZ: /* toward zero */ |
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break; |
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case FPU_CSR_RU: /* toward +infinity */ |
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if ((round || sticky) && !xs) |
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xm++; |
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break; |
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case FPU_CSR_RD: /* toward -infinity */ |
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if ((round || sticky) && xs) |
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xm++; |
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break; |
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} |
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if (round || sticky) |
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ieee754_setcx(IEEE754_INEXACT); |
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ret = ieee754dp_flong(xm); |
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DPSIGN(ret) = xs; |
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return ret; |
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}
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