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Diffstat (limited to 'arch/mips/math-emu/dp_div.c')
| -rw-r--r-- | arch/mips/math-emu/dp_div.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/arch/mips/math-emu/dp_div.c b/arch/mips/math-emu/dp_div.c new file mode 100644 index 000000000..3063ae3ab --- /dev/null +++ b/arch/mips/math-emu/dp_div.c @@ -0,0 +1,156 @@ +/* IEEE754 floating point arithmetic + * double precision: common utilities + */ +/* + * MIPS floating point support + * Copyright (C) 1994-2000 Algorithmics Ltd. + * + * This program is free software; you can distribute it and/or modify it + * under the terms of the GNU General Public License (Version 2) as + * published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "ieee754dp.h" + +union ieee754dp ieee754dp_div(union ieee754dp x, union ieee754dp y) +{ + u64 rm; + int re; + u64 bm; + + COMPXDP; + COMPYDP; + + EXPLODEXDP; + EXPLODEYDP; + + ieee754_clearcx(); + + FLUSHXDP; + FLUSHYDP; + + switch (CLPAIR(xc, yc)) { + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN): + return ieee754dp_nanxcpt(y); + + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF): + return ieee754dp_nanxcpt(x); + + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN): + return y; + + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM): + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF): + return x; + + + /* + * Infinity handling + */ + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754dp_indef(); + + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): + return ieee754dp_zero(xs ^ ys); + + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): + return ieee754dp_inf(xs ^ ys); + + /* + * Zero handling + */ + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754dp_indef(); + + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): + ieee754_setcx(IEEE754_ZERO_DIVIDE); + return ieee754dp_inf(xs ^ ys); + + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): + return ieee754dp_zero(xs == ys ? 0 : 1); + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): + DPDNORMX; + /* fall through */ + + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): + DPDNORMY; + break; + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): + DPDNORMX; + break; + + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): + break; + } + assert(xm & DP_HIDDEN_BIT); + assert(ym & DP_HIDDEN_BIT); + + /* provide rounding space */ + xm <<= 3; + ym <<= 3; + + /* now the dirty work */ + + rm = 0; + re = xe - ye; + + for (bm = DP_MBIT(DP_FBITS + 2); bm; bm >>= 1) { + if (xm >= ym) { + xm -= ym; + rm |= bm; + if (xm == 0) + break; + } + xm <<= 1; + } + + rm <<= 1; + if (xm) + rm |= 1; /* have remainder, set sticky */ + + assert(rm); + + /* + * Normalise rm to rounding precision ? + */ + while ((rm >> (DP_FBITS + 3)) == 0) { + rm <<= 1; + re--; + } + + return ieee754dp_format(xs == ys ? 0 : 1, re, rm); +} |