Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* IEEE754 floating point arithmetic |
| 2 | * single precision |
| 3 | */ |
| 4 | /* |
| 5 | * MIPS floating point support |
| 6 | * Copyright (C) 1994-2000 Algorithmics Ltd. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | * This program is free software; you can distribute it and/or modify it |
| 9 | * under the terms of the GNU General Public License (Version 2) as |
| 10 | * published by the Free Software Foundation. |
| 11 | * |
| 12 | * This program is distributed in the hope it will be useful, but WITHOUT |
| 13 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 14 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 15 | * for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License along |
| 18 | * with this program; if not, write to the Free Software Foundation, Inc., |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 19 | * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | */ |
| 21 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | #include "ieee754sp.h" |
| 23 | |
Ralf Baechle | 2209bcb | 2014-04-16 01:31:11 +0200 | [diff] [blame] | 24 | union ieee754sp ieee754sp_mul(union ieee754sp x, union ieee754sp y) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | { |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 26 | int re; |
| 27 | int rs; |
| 28 | unsigned rm; |
| 29 | unsigned short lxm; |
| 30 | unsigned short hxm; |
| 31 | unsigned short lym; |
| 32 | unsigned short hym; |
| 33 | unsigned lrm; |
| 34 | unsigned hrm; |
| 35 | unsigned t; |
| 36 | unsigned at; |
| 37 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | COMPXSP; |
| 39 | COMPYSP; |
| 40 | |
| 41 | EXPLODEXSP; |
| 42 | EXPLODEYSP; |
| 43 | |
Ralf Baechle | 9e8bad1 | 2014-04-19 00:36:32 +0200 | [diff] [blame] | 44 | ieee754_clearcx(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | |
| 46 | FLUSHXSP; |
| 47 | FLUSHYSP; |
| 48 | |
| 49 | switch (CLPAIR(xc, yc)) { |
| 50 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): |
| 51 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): |
| 52 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): |
| 53 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN): |
| 54 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN): |
| 55 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN): |
| 56 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN): |
| 57 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO): |
| 58 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM): |
| 59 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM): |
| 60 | case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF): |
Ralf Baechle | 9e8bad1 | 2014-04-19 00:36:32 +0200 | [diff] [blame] | 61 | ieee754_setcx(IEEE754_INVALID_OPERATION); |
Ralf Baechle | 90efba3 | 2014-04-25 03:19:57 +0200 | [diff] [blame] | 62 | return ieee754sp_nanxcpt(ieee754sp_indef()); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
| 64 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN): |
| 65 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN): |
| 66 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN): |
| 67 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN): |
| 68 | return y; |
| 69 | |
| 70 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): |
| 71 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO): |
| 72 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM): |
| 73 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM): |
| 74 | case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF): |
| 75 | return x; |
| 76 | |
| 77 | |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 78 | /* |
| 79 | * Infinity handling |
| 80 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): |
| 82 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): |
Ralf Baechle | 9e8bad1 | 2014-04-19 00:36:32 +0200 | [diff] [blame] | 83 | ieee754_setcx(IEEE754_INVALID_OPERATION); |
Ralf Baechle | 90efba3 | 2014-04-25 03:19:57 +0200 | [diff] [blame] | 84 | return ieee754sp_indef(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | |
| 86 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): |
| 87 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): |
| 88 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): |
| 89 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): |
| 90 | case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): |
| 91 | return ieee754sp_inf(xs ^ ys); |
| 92 | |
| 93 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): |
| 94 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): |
| 95 | case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): |
| 96 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): |
| 97 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): |
| 98 | return ieee754sp_zero(xs ^ ys); |
| 99 | |
| 100 | |
| 101 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): |
| 102 | SPDNORMX; |
| 103 | |
| 104 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): |
| 105 | SPDNORMY; |
| 106 | break; |
| 107 | |
| 108 | case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): |
| 109 | SPDNORMX; |
| 110 | break; |
| 111 | |
| 112 | case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): |
| 113 | break; |
| 114 | } |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 115 | /* rm = xm * ym, re = xe+ye basically */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | assert(xm & SP_HIDDEN_BIT); |
| 117 | assert(ym & SP_HIDDEN_BIT); |
| 118 | |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 119 | re = xe + ye; |
| 120 | rs = xs ^ ys; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 122 | /* shunt to top of word */ |
| 123 | xm <<= 32 - (SP_FBITS + 1); |
| 124 | ym <<= 32 - (SP_FBITS + 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 126 | /* |
| 127 | * Multiply 32 bits xm, ym to give high 32 bits rm with stickness. |
| 128 | */ |
| 129 | lxm = xm & 0xffff; |
| 130 | hxm = xm >> 16; |
| 131 | lym = ym & 0xffff; |
| 132 | hym = ym >> 16; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 134 | lrm = lxm * lym; /* 16 * 16 => 32 */ |
| 135 | hrm = hxm * hym; /* 16 * 16 => 32 */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 137 | t = lxm * hym; /* 16 * 16 => 32 */ |
| 138 | at = lrm + (t << 16); |
| 139 | hrm += at < lrm; |
| 140 | lrm = at; |
| 141 | hrm = hrm + (t >> 16); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 142 | |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 143 | t = hxm * lym; /* 16 * 16 => 32 */ |
| 144 | at = lrm + (t << 16); |
| 145 | hrm += at < lrm; |
| 146 | lrm = at; |
| 147 | hrm = hrm + (t >> 16); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 149 | rm = hrm | (lrm != 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 151 | /* |
| 152 | * Sticky shift down to normal rounding precision. |
| 153 | */ |
| 154 | if ((int) rm < 0) { |
| 155 | rm = (rm >> (32 - (SP_FBITS + 1 + 3))) | |
| 156 | ((rm << (SP_FBITS + 1 + 3)) != 0); |
| 157 | re++; |
| 158 | } else { |
| 159 | rm = (rm >> (32 - (SP_FBITS + 1 + 3 + 1))) | |
| 160 | ((rm << (SP_FBITS + 1 + 3 + 1)) != 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | } |
Ralf Baechle | 3f7cac4 | 2014-04-26 01:49:14 +0200 | [diff] [blame] | 162 | assert(rm & (SP_HIDDEN_BIT << 3)); |
| 163 | |
| 164 | return ieee754sp_format(rs, re, rm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | } |