diff options
Diffstat (limited to 'arch/mips/math-emu/sp_mul.c')
| -rw-r--r-- | arch/mips/math-emu/sp_mul.c | 127 |
1 files changed, 61 insertions, 66 deletions
diff --git a/arch/mips/math-emu/sp_mul.c b/arch/mips/math-emu/sp_mul.c index 0e19d0edd3f9..890c13a2965e 100644 --- a/arch/mips/math-emu/sp_mul.c +++ b/arch/mips/math-emu/sp_mul.c @@ -5,8 +5,6 @@ * 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. @@ -18,16 +16,25 @@ * * 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. - * - * ######################################################################## + * 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; @@ -68,8 +75,9 @@ union ieee754sp ieee754sp_mul(union ieee754sp x, union ieee754sp y) return x; - /* Infinity handling */ - + /* + * Infinity handling + */ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): ieee754_setcx(IEEE754_INVALID_OPERATION); @@ -108,63 +116,50 @@ union ieee754sp ieee754sp_mul(union ieee754sp x, union ieee754sp y) assert(xm & SP_HIDDEN_BIT); assert(ym & SP_HIDDEN_BIT); - { - int re = xe + ye; - int rs = xs ^ ys; - unsigned rm; - - /* shunt to top of word */ - xm <<= 32 - (SP_FBITS + 1); - ym <<= 32 - (SP_FBITS + 1); - - /* multiply 32bits xm,ym to give high 32bits rm with stickness - */ - { - unsigned short lxm = xm & 0xffff; - unsigned short hxm = xm >> 16; - unsigned short lym = ym & 0xffff; - unsigned short hym = ym >> 16; - unsigned lrm; - unsigned hrm; - - lrm = lxm * lym; /* 16 * 16 => 32 */ - hrm = hxm * hym; /* 16 * 16 => 32 */ - - { - unsigned t = lxm * hym; /* 16 * 16 => 32 */ - { - unsigned at = lrm + (t << 16); - hrm += at < lrm; - lrm = at; - } - hrm = hrm + (t >> 16); - } - - { - unsigned t = hxm * lym; /* 16 * 16 => 32 */ - { - unsigned 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); + 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); } |