projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* IEEE754 floating point arithmetic |
| 2 | * double precision: common utilities | |
| 3 | */ | |
| 4 | /* | |
| 5 | * MIPS floating point support | |
| 6 | * Copyright (C) 1994-2000 Algorithmics Ltd. | |
| 1da177e4 | 7 | * |
| 1da177e4 LT |
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., | |
| 3f7cac41 | 19 | * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 1da177e4 LT |
20 | */ |
| 21 | ||
| 1da177e4 LT |
22 | #include "ieee754dp.h" |
| 23 | ||
| 2209bcb1 | 24 | int ieee754dp_tint(union ieee754dp x) |
| 1da177e4 | 25 | { |
| 3f7cac41 RB |
26 | u64 residue; |
| 27 | int round; | |
| 28 | int sticky; | |
| 29 | int odd; | |
| 30 | ||
| 1da177e4 LT |
31 | COMPXDP; |
| 32 | ||
| 9e8bad1f | 33 | ieee754_clearcx(); |
| 1da177e4 LT |
34 | |
| 35 | EXPLODEXDP; | |
| 36 | FLUSHXDP; | |
| 37 | ||
| 38 | switch (xc) { | |
| 39 | case IEEE754_CLASS_SNAN: | |
| 40 | case IEEE754_CLASS_QNAN: | |
| 41 | case IEEE754_CLASS_INF: | |
| 9e8bad1f | 42 | ieee754_setcx(IEEE754_INVALID_OPERATION); |
| 90efba36 | 43 | return ieee754si_indef(); |
| 3f7cac41 | 44 | |
| 1da177e4 LT |
45 | case IEEE754_CLASS_ZERO: |
| 46 | return 0; | |
| 3f7cac41 | 47 | |
| 1da177e4 LT |
48 | case IEEE754_CLASS_DNORM: |
| 49 | case IEEE754_CLASS_NORM: | |
| 50 | break; | |
| 51 | } | |
| 52 | if (xe > 31) { | |
| 53 | /* Set invalid. We will only use overflow for floating | |
| 54 | point overflow */ | |
| 9e8bad1f | 55 | ieee754_setcx(IEEE754_INVALID_OPERATION); |
| 90efba36 | 56 | return ieee754si_indef(); |
| 1da177e4 LT |
57 | } |
| 58 | /* oh gawd */ | |
| ad8fb553 RB |
59 | if (xe > DP_FBITS) { |
| 60 | xm <<= xe - DP_FBITS; | |
| 61 | } else if (xe < DP_FBITS) { | |
| 1da177e4 LT |
62 | if (xe < -1) { |
| 63 | residue = xm; | |
| 64 | round = 0; | |
| 65 | sticky = residue != 0; | |
| 66 | xm = 0; | |
| 6337f5e5 | 67 | } else { |
| ad8fb553 | 68 | residue = xm << (64 - DP_FBITS + xe); |
| 1da177e4 LT |
69 | round = (residue >> 63) != 0; |
| 70 | sticky = (residue << 1) != 0; | |
| ad8fb553 | 71 | xm >>= DP_FBITS - xe; |
| 1da177e4 LT |
72 | } |
| 73 | /* Note: At this point upper 32 bits of xm are guaranteed | |
| 74 | to be zero */ | |
| 75 | odd = (xm & 0x1) != 0x0; | |
| 76 | switch (ieee754_csr.rm) { | |
| 56a64733 | 77 | case FPU_CSR_RN: |
| 1da177e4 LT |
78 | if (round && (sticky || odd)) |
| 79 | xm++; | |
| 80 | break; | |
| 56a64733 | 81 | case FPU_CSR_RZ: |
| 1da177e4 | 82 | break; |
| 56a64733 | 83 | case FPU_CSR_RU: /* toward +Infinity */ |
| 1da177e4 LT |
84 | if ((round || sticky) && !xs) |
| 85 | xm++; | |
| 86 | break; | |
| 56a64733 | 87 | case FPU_CSR_RD: /* toward -Infinity */ |
| 1da177e4 LT |
88 | if ((round || sticky) && xs) |
| 89 | xm++; | |
| 90 | break; | |
| 91 | } | |
| 92 | /* look for valid corner case 0x80000000 */ | |
| 93 | if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) { | |
| 94 | /* This can happen after rounding */ | |
| 9e8bad1f | 95 | ieee754_setcx(IEEE754_INVALID_OPERATION); |
| 90efba36 | 96 | return ieee754si_indef(); |
| 1da177e4 LT |
97 | } |
| 98 | if (round || sticky) | |
| 9e8bad1f | 99 | ieee754_setcx(IEEE754_INEXACT); |
| 1da177e4 LT |
100 | } |
| 101 | if (xs) | |
| 102 | return -xm; | |
| 103 | else | |
| 104 | return xm; | |
| 105 | } |