| /* 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., |
| * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. |
| * |
| * ######################################################################## |
| */ |
| |
| |
| #include "ieee754dp.h" |
| |
| union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y) |
| { |
| COMPXDP; |
| COMPYDP; |
| |
| EXPLODEXDP; |
| EXPLODEYDP; |
| |
| ieee754_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): |
| ieee754_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): |
| ieee754_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 basically */ |
| 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); |
| } |
| } |