diff options
Diffstat (limited to 'kernel/arch/mips/math-emu/sp_add.c')
| -rw-r--r-- | kernel/arch/mips/math-emu/sp_add.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/kernel/arch/mips/math-emu/sp_add.c b/kernel/arch/mips/math-emu/sp_add.c new file mode 100644 index 000000000..f1c87b07d --- /dev/null +++ b/kernel/arch/mips/math-emu/sp_add.c @@ -0,0 +1,176 @@ +/* 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_add(union ieee754sp x, union ieee754sp y) +{ + int s; + + 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_INF): + if (xs == ys) + return x; + ieee754_setcx(IEEE754_INVALID_OPERATION); + return ieee754sp_indef(); + + 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 y; + + 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 x; + + /* + * Zero handling + */ + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): + if (xs == ys) + return x; + else + return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD); + + case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): + return x; + + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): + case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): + return y; + + case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): + SPDNORMX; + + /* FALL THROUGH */ + + 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 guard, round and stick bit space. + */ + xm <<= 3; + ym <<= 3; + + if (xe > ye) { + /* + * Have to shift y fraction right to align. + */ + s = xe - ye; + SPXSRSYn(s); + } else if (ye > xe) { + /* + * Have to shift x fraction right to align. + */ + s = ye - xe; + SPXSRSXn(s); + } + assert(xe == ye); + assert(xe <= SP_EMAX); + + if (xs == ys) { + /* + * Generate 28 bit result of adding two 27 bit numbers + * leaving result in xm, xs and xe. + */ + xm = xm + ym; + + if (xm >> (SP_FBITS + 1 + 3)) { /* carry out */ + SPXSRSX1(); + } + } else { + if (xm >= ym) { + xm = xm - ym; + } else { + xm = ym - xm; + xs = ys; + } + if (xm == 0) + return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD); + + /* + * Normalize in extended single precision + */ + while ((xm >> (SP_FBITS + 3)) == 0) { + xm <<= 1; + xe--; + } + } + + return ieee754sp_format(xs, xe, xm); +} |