| /* 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., |
| * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. |
| * |
| * ######################################################################## |
| */ |
| |
| |
| #include "ieee754sp.h" |
| |
| union ieee754sp ieee754sp_add(union ieee754sp x, union ieee754sp y) |
| { |
| COMPXSP; |
| COMPYSP; |
| |
| EXPLODEXSP; |
| EXPLODEYSP; |
| |
| ieee754_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): |
| ieee754_setcx(IEEE754_INVALID_OPERATION); |
| return ieee754sp_nanxcpt(ieee754sp_indef(), "add", 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): |
| if (xs == ys) |
| return x; |
| ieee754_setcx(IEEE754_INVALID_OPERATION); |
| return ieee754sp_xcpt(ieee754sp_indef(), "add", 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 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 == |
| IEEE754_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; |
| |
| 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 |
| */ |
| int s = xe - ye; |
| SPXSRSYn(s); |
| } else if (ye > xe) { |
| /* have to shift x fraction right to align |
| */ |
| int 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,xe |
| */ |
| xm = xm + ym; |
| xe = xe; |
| xs = xs; |
| |
| if (xm >> (SP_MBITS + 1 + 3)) { /* carry out */ |
| SPXSRSX1(); |
| } |
| } else { |
| if (xm >= ym) { |
| xm = xm - ym; |
| xe = xe; |
| xs = xs; |
| } else { |
| xm = ym - xm; |
| xe = xe; |
| xs = ys; |
| } |
| if (xm == 0) |
| return ieee754sp_zero(ieee754_csr.rm == |
| IEEE754_RD); |
| |
| /* normalize in extended single precision */ |
| while ((xm >> (SP_MBITS + 3)) == 0) { |
| xm <<= 1; |
| xe--; |
| } |
| |
| } |
| SPNORMRET2(xs, xe, xm, "add", x, y); |
| } |