| 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. |
| 7 | * http://www.algor.co.uk |
| 8 | * |
| 9 | * ######################################################################## |
| 10 | * |
| 11 | * This program is free software; you can distribute it and/or modify it |
| 12 | * under the terms of the GNU General Public License (Version 2) as |
| 13 | * published by the Free Software Foundation. |
| 14 | * |
| 15 | * This program is distributed in the hope it will be useful, but WITHOUT |
| 16 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 17 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 18 | * for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License along |
| 21 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 22 | * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. |
| 23 | * |
| 24 | * ######################################################################## |
| 25 | */ |
| 26 | |
| 27 | |
| 28 | #include "ieee754sp.h" |
| 29 | |
| 30 | ieee754sp ieee754sp_fdp(ieee754dp x) |
| 31 | { |
| 32 | COMPXDP; |
| 33 | ieee754sp nan; |
| 34 | |
| 35 | EXPLODEXDP; |
| 36 | |
| 37 | CLEARCX; |
| 38 | |
| 39 | FLUSHXDP; |
| 40 | |
| 41 | switch (xc) { |
| 42 | case IEEE754_CLASS_SNAN: |
| 43 | SETCX(IEEE754_INVALID_OPERATION); |
| 44 | return ieee754sp_nanxcpt(ieee754sp_indef(), "fdp"); |
| 45 | case IEEE754_CLASS_QNAN: |
| 46 | nan = buildsp(xs, SP_EMAX + 1 + SP_EBIAS, (u32) |
| 47 | (xm >> (DP_MBITS - SP_MBITS))); |
| 48 | if (!ieee754sp_isnan(nan)) |
| 49 | nan = ieee754sp_indef(); |
| 50 | return ieee754sp_nanxcpt(nan, "fdp", x); |
| 51 | case IEEE754_CLASS_INF: |
| 52 | return ieee754sp_inf(xs); |
| 53 | case IEEE754_CLASS_ZERO: |
| 54 | return ieee754sp_zero(xs); |
| 55 | case IEEE754_CLASS_DNORM: |
| 56 | /* can't possibly be sp representable */ |
| 57 | SETCX(IEEE754_UNDERFLOW); |
| 58 | SETCX(IEEE754_INEXACT); |
| 59 | if ((ieee754_csr.rm == IEEE754_RU && !xs) || |
| 60 | (ieee754_csr.rm == IEEE754_RD && xs)) |
| 61 | return ieee754sp_xcpt(ieee754sp_mind(xs), "fdp", x); |
| 62 | return ieee754sp_xcpt(ieee754sp_zero(xs), "fdp", x); |
| 63 | case IEEE754_CLASS_NORM: |
| 64 | break; |
| 65 | } |
| 66 | |
| 67 | { |
| 68 | u32 rm; |
| 69 | |
| 70 | /* convert from DP_MBITS to SP_MBITS+3 with sticky right shift |
| 71 | */ |
| 72 | rm = (xm >> (DP_MBITS - (SP_MBITS + 3))) | |
| 73 | ((xm << (64 - (DP_MBITS - (SP_MBITS + 3)))) != 0); |
| 74 | |
| 75 | SPNORMRET1(xs, xe, rm, "fdp", x); |
| 76 | } |
| 77 | } |