sp_div.rar_floating

/* IEEE754 floating point arithmetic * single precision */ /* * MIPS floating point support * * * ######################################################################## * * 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 "ieee754sp.h" ieee754sp ieee754sp_div(ieee754sp x, ieee754sp y) { COMPXSP; COMPYSP; EXPLODEXSP; EXPLODEYSP; CLEARCX; FLUSHXSP; FLUSHYSP; 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 ieee754sp_nanxcpt(ieee754sp_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 ieee754sp_xcpt(ieee754sp_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 ieee754sp_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 ieee754sp_inf(xs ^ ys); /* Zero handling */ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): SETCX(IEEE754_INVALID_OPERATION); return ieee754sp_xcpt(ieee754sp_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 ieee754sp_xcpt(ieee754sp_inf(xs ^ ys), "div", x, y); case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): return ieee754sp_zero(xs == ys ? 0 : 1); case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): SPDNORMX; case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): SPDNORMY; break; case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): SPDNORMX; break; case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): break; } assert(xm & SP_HIDDEN_BIT); assert(ym & SP_HIDDEN_BIT); /* provide rounding space */ xm <<= 3; ym <<= 3; { /* now the dirty work */ unsigned rm = 0; int re = xe - ye; unsigned bm; for (bm = SP_MBIT(SP_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 >> (SP_MBITS + 3)) == 0) { rm <<= 1; re--; } SPNORMRET2(xs == ys ? 0 : 1, re, rm, "div", x, y); } }