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100 lines
2.0 KiB
100 lines
2.0 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* IEEE754 floating point arithmetic |
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* single precision |
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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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*/ |
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#include "ieee754sp.h" |
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int ieee754sp_tint(union ieee754sp x) |
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{ |
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u32 residue; |
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int round; |
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int sticky; |
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int odd; |
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COMPXSP; |
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ieee754_clearcx(); |
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EXPLODEXSP; |
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FLUSHXSP; |
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switch (xc) { |
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case IEEE754_CLASS_SNAN: |
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case IEEE754_CLASS_QNAN: |
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ieee754_setcx(IEEE754_INVALID_OPERATION); |
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return ieee754si_indef(); |
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case IEEE754_CLASS_INF: |
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ieee754_setcx(IEEE754_INVALID_OPERATION); |
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return ieee754si_overflow(xs); |
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case IEEE754_CLASS_ZERO: |
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return 0; |
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case IEEE754_CLASS_DNORM: |
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case IEEE754_CLASS_NORM: |
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break; |
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} |
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if (xe >= 31) { |
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/* look for valid corner case */ |
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if (xe == 31 && xs && xm == SP_HIDDEN_BIT) |
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return -0x80000000; |
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/* Set invalid. We will only use overflow for floating |
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point overflow */ |
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ieee754_setcx(IEEE754_INVALID_OPERATION); |
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return ieee754si_overflow(xs); |
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} |
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/* oh gawd */ |
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if (xe > SP_FBITS) { |
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xm <<= xe - SP_FBITS; |
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} else { |
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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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/* Shifting a u32 32 times does not work, |
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* so we do it in two steps. Be aware that xe |
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* may be -1 */ |
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residue = xm << (xe + 1); |
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residue <<= 31 - SP_FBITS; |
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round = (residue >> 31) != 0; |
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sticky = (residue << 1) != 0; |
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xm >>= SP_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: |
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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: |
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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 ((xm >> 31) != 0) { |
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/* This can happen after rounding */ |
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ieee754_setcx(IEEE754_INVALID_OPERATION); |
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return ieee754si_overflow(xs); |
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} |
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if (round || sticky) |
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ieee754_setcx(IEEE754_INEXACT); |
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} |
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if (xs) |
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return -xm; |
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else |
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return xm; |
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}
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