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Diffstat (limited to 'arch/mips/math-emu/dp_mul.c')
| -rw-r--r-- | arch/mips/math-emu/dp_mul.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/arch/mips/math-emu/dp_mul.c b/arch/mips/math-emu/dp_mul.c new file mode 100644 index 0000000..f237390 --- /dev/null +++ b/arch/mips/math-emu/dp_mul.c @@ -0,0 +1,177 @@ +/* IEEE754 floating point arithmetic + * double precision: common utilities + */ +/* + * MIPS floating point support + * Copyright (C) 1994-2000 Algorithmics Ltd. + * http://www.algor.co.uk + * + * ######################################################################## + * + * 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., + * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. + * + * ######################################################################## + */ + + +#include "ieee754dp.h" + +ieee754dp ieee754dp_mul(ieee754dp x, ieee754dp y) +{ + COMPXDP; + COMPYDP; + + EXPLODEXDP; + EXPLODEYDP; + + CLEARCX; + + FLUSHXDP; + FLUSHYDP; + + switch (CLPAIR(xc, yc)) { + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): + case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_SNAN, 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): + 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): + SETCX(IEEE754_INVALID_OPERATION); + return ieee754dp_nanxcpt(ieee754dp_indef(), "mul", x, y); + + 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_ZERO): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): + SETCX(IEEE754_INVALID_OPERATION); + return ieee754dp_xcpt(ieee754dp_indef(), "mul", x, y); + + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): + case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): + return ieee754dp_inf(xs ^ ys); + + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): + return ieee754dp_zero(xs ^ ys); + + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): + DPDNORMX; + + 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; + } + /* rm = xm * ym, re = xe+ye basicly */ + assert(xm & DP_HIDDEN_BIT); + assert(ym & DP_HIDDEN_BIT); + { + int re = xe + ye; + int rs = xs ^ ys; + u64 rm; + + /* shunt to top of word */ + xm <<= 64 - (DP_MBITS + 1); + ym <<= 64 - (DP_MBITS + 1); + + /* multiply 32bits xm,ym to give high 32bits rm with stickness + */ + + /* 32 * 32 => 64 */ +#define DPXMULT(x,y) ((u64)(x) * (u64)y) + + { + unsigned lxm = xm; + unsigned hxm = xm >> 32; + unsigned lym = ym; + unsigned hym = ym >> 32; + u64 lrm; + u64 hrm; + + lrm = DPXMULT(lxm, lym); + hrm = DPXMULT(hxm, hym); + + { + u64 t = DPXMULT(lxm, hym); + { + u64 at = + lrm + (t << 32); + hrm += at < lrm; + lrm = at; + } + hrm = hrm + (t >> 32); + } + + { + u64 t = DPXMULT(hxm, lym); + { + u64 at = + lrm + (t << 32); + hrm += at < lrm; + lrm = at; + } + hrm = hrm + (t >> 32); + } + rm = hrm | (lrm != 0); + } + + /* + * sticky shift down to normal rounding precision + */ + if ((s64) rm < 0) { + rm = + (rm >> (64 - (DP_MBITS + 1 + 3))) | + ((rm << (DP_MBITS + 1 + 3)) != 0); + re++; + } else { + rm = + (rm >> (64 - (DP_MBITS + 1 + 3 + 1))) | + ((rm << (DP_MBITS + 1 + 3 + 1)) != 0); + } + assert(rm & (DP_HIDDEN_BIT << 3)); + DPNORMRET2(rs, re, rm, "mul", x, y); + } +} |