mirror of https://gitee.com/openkylin/linux.git
74 lines
1.4 KiB
C
74 lines
1.4 KiB
C
// 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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#include "ieee754dp.h"
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static inline union ieee754sp ieee754sp_nan_fdp(int xs, u64 xm)
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{
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return buildsp(xs, SP_EMAX + 1 + SP_EBIAS,
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xm >> (DP_FBITS - SP_FBITS));
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}
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union ieee754sp ieee754sp_fdp(union ieee754dp x)
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{
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union ieee754sp y;
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u32 rm;
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COMPXDP;
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COMPYSP;
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EXPLODEXDP;
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ieee754_clearcx();
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FLUSHXDP;
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switch (xc) {
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case IEEE754_CLASS_SNAN:
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x = ieee754dp_nanxcpt(x);
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EXPLODEXDP;
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fallthrough;
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case IEEE754_CLASS_QNAN:
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y = ieee754sp_nan_fdp(xs, xm);
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if (!ieee754_csr.nan2008) {
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EXPLODEYSP;
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if (!ieee754_class_nan(yc))
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y = ieee754sp_indef();
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}
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return y;
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case IEEE754_CLASS_INF:
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return ieee754sp_inf(xs);
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case IEEE754_CLASS_ZERO:
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return ieee754sp_zero(xs);
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case IEEE754_CLASS_DNORM:
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/* can't possibly be sp representable */
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ieee754_setcx(IEEE754_UNDERFLOW);
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ieee754_setcx(IEEE754_INEXACT);
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if ((ieee754_csr.rm == FPU_CSR_RU && !xs) ||
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(ieee754_csr.rm == FPU_CSR_RD && xs))
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return ieee754sp_mind(xs);
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return ieee754sp_zero(xs);
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case IEEE754_CLASS_NORM:
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break;
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}
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/*
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* Convert from DP_FBITS to SP_FBITS+3 with sticky right shift.
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*/
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rm = (xm >> (DP_FBITS - (SP_FBITS + 3))) |
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((xm << (64 - (DP_FBITS - (SP_FBITS + 3)))) != 0);
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return ieee754sp_format(xs, xe, rm);
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}
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