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55 lines
2.1 KiB
55 lines
2.1 KiB
/* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "libavutil/float2half.h" |
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void ff_init_float2half_tables(Float2HalfTables *t) |
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{ |
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#if !HAVE_FAST_FLOAT16 |
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for (int i = 0; i < 256; i++) { |
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int e = i - 127; |
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if (e < -24) { // Very small numbers map to zero |
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t->basetable[i|0x000] = 0x0000; |
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t->basetable[i|0x100] = 0x8000; |
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t->shifttable[i|0x000] = 24; |
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t->shifttable[i|0x100] = 24; |
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} else if (e < -14) { // Small numbers map to denorms |
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t->basetable[i|0x000] = (0x0400>>(-e-14)); |
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t->basetable[i|0x100] = (0x0400>>(-e-14)) | 0x8000; |
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t->shifttable[i|0x000] = -e-1; |
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t->shifttable[i|0x100] = -e-1; |
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} else if (e <= 15) { // Normal numbers just lose precision |
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t->basetable[i|0x000] = ((e + 15) << 10); |
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t->basetable[i|0x100] = ((e + 15) << 10) | 0x8000; |
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t->shifttable[i|0x000] = 13; |
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t->shifttable[i|0x100] = 13; |
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} else if (e < 128) { // Large numbers map to Infinity |
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t->basetable[i|0x000] = 0x7C00; |
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t->basetable[i|0x100] = 0xFC00; |
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t->shifttable[i|0x000] = 24; |
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t->shifttable[i|0x100] = 24; |
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} else { // Infinity and NaN's stay Infinity and NaN's |
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t->basetable[i|0x000] = 0x7C00; |
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t->basetable[i|0x100] = 0xFC00; |
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t->shifttable[i|0x000] = 13; |
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t->shifttable[i|0x100] = 13; |
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} |
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} |
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#endif |
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}
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