diff options
Diffstat (limited to 'kernel/arch/mips/math-emu/sp_mul.c')
| -rw-r--r-- | kernel/arch/mips/math-emu/sp_mul.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/kernel/arch/mips/math-emu/sp_mul.c b/kernel/arch/mips/math-emu/sp_mul.c new file mode 100644 index 000000000..d910c43a6 --- /dev/null +++ b/kernel/arch/mips/math-emu/sp_mul.c @@ -0,0 +1,166 @@ +/* IEEE754 floating point arithmetic + * single precision + */ +/* + * 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., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "ieee754sp.h" + +union ieee754sp ieee754sp_mul(union ieee754sp x, union ieee754sp y) +{ + int re; + int rs; + unsigned rm; + unsigned short lxm; + unsigned short hxm; + unsigned short lym; + unsigned short hym; + unsigned lrm; + unsigned hrm; + unsigned t; + unsigned at; + + COMPXSP; + COMPYSP; + + EXPLODEXSP; + EXPLODEYSP; + + ieee754_clearcx(); + + FLUSHXSP; + FLUSHYSP; + + switch (CLPAIR(xc, yc)) { + case CLPAIR(IEEE754_CLASS_QNAN, 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): + return ieee754sp_nanxcpt(y); + + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): + case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): + 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): + return ieee754sp_nanxcpt(x); + + 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 ieee754sp_indef(); + + 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 ieee754sp_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 ieee754sp_zero(xs ^ ys); + + + 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; + } + /* rm = xm * ym, re = xe+ye basically */ + assert(xm & SP_HIDDEN_BIT); + assert(ym & SP_HIDDEN_BIT); + + re = xe + ye; + rs = xs ^ ys; + + /* shunt to top of word */ + xm <<= 32 - (SP_FBITS + 1); + ym <<= 32 - (SP_FBITS + 1); + + /* + * Multiply 32 bits xm, ym to give high 32 bits rm with stickness. + */ + lxm = xm & 0xffff; + hxm = xm >> 16; + lym = ym & 0xffff; + hym = ym >> 16; + + lrm = lxm * lym; /* 16 * 16 => 32 */ + hrm = hxm * hym; /* 16 * 16 => 32 */ + + t = lxm * hym; /* 16 * 16 => 32 */ + at = lrm + (t << 16); + hrm += at < lrm; + lrm = at; + hrm = hrm + (t >> 16); + + t = hxm * lym; /* 16 * 16 => 32 */ + at = lrm + (t << 16); + hrm += at < lrm; + lrm = at; + hrm = hrm + (t >> 16); + + rm = hrm | (lrm != 0); + + /* + * Sticky shift down to normal rounding precision. + */ + if ((int) rm < 0) { + rm = (rm >> (32 - (SP_FBITS + 1 + 3))) | + ((rm << (SP_FBITS + 1 + 3)) != 0); + re++; + } else { + rm = (rm >> (32 - (SP_FBITS + 1 + 3 + 1))) | + ((rm << (SP_FBITS + 1 + 3 + 1)) != 0); + } + assert(rm & (SP_HIDDEN_BIT << 3)); + + return ieee754sp_format(rs, re, rm); +} |