diff options
Diffstat (limited to 'arch/mips/math-emu/dp_tint.c')
-rw-r--r-- | arch/mips/math-emu/dp_tint.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/arch/mips/math-emu/dp_tint.c b/arch/mips/math-emu/dp_tint.c new file mode 100644 index 0000000000..0e6ad35e7c --- /dev/null +++ b/arch/mips/math-emu/dp_tint.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* IEEE754 floating point arithmetic + * double precision: common utilities + */ +/* + * MIPS floating point support + * Copyright (C) 1994-2000 Algorithmics Ltd. + */ + +#include "ieee754dp.h" + +int ieee754dp_tint(union ieee754dp x) +{ + u64 residue; + int round; + int sticky; + int odd; + + COMPXDP; + + ieee754_clearcx(); + + EXPLODEXDP; + FLUSHXDP; + + switch (xc) { + case IEEE754_CLASS_SNAN: + case IEEE754_CLASS_QNAN: + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754si_indef(); + + case IEEE754_CLASS_INF: + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754si_overflow(xs); + + case IEEE754_CLASS_ZERO: + return 0; + + case IEEE754_CLASS_DNORM: + case IEEE754_CLASS_NORM: + break; + } + if (xe > 31) { + /* Set invalid. We will only use overflow for floating + point overflow */ + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754si_overflow(xs); + } + /* oh gawd */ + if (xe > DP_FBITS) { + xm <<= xe - DP_FBITS; + } else if (xe < DP_FBITS) { + if (xe < -1) { + residue = xm; + round = 0; + sticky = residue != 0; + xm = 0; + } else { + residue = xm << (64 - DP_FBITS + xe); + round = (residue >> 63) != 0; + sticky = (residue << 1) != 0; + xm >>= DP_FBITS - xe; + } + /* Note: At this point upper 32 bits of xm are guaranteed + to be zero */ + odd = (xm & 0x1) != 0x0; + switch (ieee754_csr.rm) { + case FPU_CSR_RN: + if (round && (sticky || odd)) + xm++; + break; + case FPU_CSR_RZ: + break; + case FPU_CSR_RU: /* toward +Infinity */ + if ((round || sticky) && !xs) + xm++; + break; + case FPU_CSR_RD: /* toward -Infinity */ + if ((round || sticky) && xs) + xm++; + break; + } + /* look for valid corner case 0x80000000 */ + if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) { + /* This can happen after rounding */ + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754si_overflow(xs); + } + if (round || sticky) + ieee754_setcx(IEEE754_INEXACT); + } + if (xs) + return -xm; + else + return xm; +} |