| /* 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_div(union ieee754dp x, union 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(), "div", 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_INF): |
| SETCX(IEEE754_INVALID_OPERATION); |
| return ieee754dp_xcpt(ieee754dp_indef(), "div", x, y); |
| |
| 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): |
| SETCX(IEEE754_INVALID_OPERATION); |
| return ieee754dp_xcpt(ieee754dp_indef(), "div", x, y); |
| |
| case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): |
| case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): |
| SETCX(IEEE754_ZERO_DIVIDE); |
| return ieee754dp_xcpt(ieee754dp_inf(xs ^ ys), "div", x, y); |
| |
| 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; |
| |
| 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 */ |
| |
| u64 rm = 0; |
| int re = xe - ye; |
| u64 bm; |
| |
| for (bm = DP_MBIT(DP_MBITS + 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_MBITS + 3)) == 0) { |
| rm <<= 1; |
| re--; |
| } |
| |
| DPNORMRET2(xs == ys ? 0 : 1, re, rm, "div", x, y); |
| } |
| } |