diff options
Diffstat (limited to 'arch/mips/math-emu/dp_modf.c')
-rw-r--r-- | arch/mips/math-emu/dp_modf.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/arch/mips/math-emu/dp_modf.c b/arch/mips/math-emu/dp_modf.c new file mode 100644 index 00000000000..25861a42c36 --- /dev/null +++ b/arch/mips/math-emu/dp_modf.c @@ -0,0 +1,80 @@ +/* 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" + +/* modf function is always exact for a finite number +*/ +ieee754dp ieee754dp_modf(ieee754dp x, ieee754dp * ip) +{ + COMPXDP; + + CLEARCX; + + EXPLODEXDP; + + switch (xc) { + case IEEE754_CLASS_SNAN: + case IEEE754_CLASS_QNAN: + case IEEE754_CLASS_INF: + case IEEE754_CLASS_ZERO: + *ip = x; + return x; + case IEEE754_CLASS_DNORM: + /* far to small */ + *ip = ieee754dp_zero(xs); + return x; + case IEEE754_CLASS_NORM: + break; + } + if (xe < 0) { + *ip = ieee754dp_zero(xs); + return x; + } + if (xe >= DP_MBITS) { + *ip = x; + return ieee754dp_zero(xs); + } + /* generate ipart mantissa by clearing bottom bits + */ + *ip = builddp(xs, xe + DP_EBIAS, + ((xm >> (DP_MBITS - xe)) << (DP_MBITS - xe)) & + ~DP_HIDDEN_BIT); + + /* generate fpart mantissa by clearing top bits + * and normalizing (must be able to normalize) + */ + xm = (xm << (64 - (DP_MBITS - xe))) >> (64 - (DP_MBITS - xe)); + if (xm == 0) + return ieee754dp_zero(xs); + + while ((xm >> DP_MBITS) == 0) { + xm <<= 1; + xe--; + } + return builddp(xs, xe + DP_EBIAS, xm & ~DP_HIDDEN_BIT); +} |