| J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | #include "AlphaMath.h" |
| 27 | |
| 28 | unsigned char mul8table[256][256]; |
| 29 | unsigned char div8table[256][256]; |
| 30 | |
| 31 | void initAlphaTables() |
| 32 | { |
| 33 | unsigned int i; |
| 34 | unsigned int j; |
| 35 | |
| 36 | for (i = 1; i < 256; i++) { /* SCALE == (1 << 24) */ |
| 37 | int inc = (i << 16) + (i<<8) + i; /* approx. SCALE * (i/255.0) */ |
| 38 | int val = inc + (1 << 23); /* inc + SCALE*0.5 */ |
| 39 | for (j = 1; j < 256; j++) { |
| 40 | mul8table[i][j] = (val >> 24); /* val / SCALE */ |
| 41 | val += inc; |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | for (i = 1; i < 256; i++) { |
| 46 | unsigned int inc; |
| 47 | unsigned int val; |
| 48 | inc = 0xff; |
| 49 | inc = ((inc << 24) + i/2) / i; |
| 50 | val = (1 << 23); |
| 51 | for (j = 0; j < i; j++) { |
| 52 | div8table[i][j] = (val >> 24); |
| 53 | val += inc; |
| 54 | } |
| 55 | for (j = i; j < 256; j++) { |
| 56 | div8table[i][j] = 255; |
| 57 | } |
| 58 | } |
| 59 | } |