diff options
Diffstat (limited to 'libavutil/float2half.h')
| -rw-r--r-- | libavutil/float2half.h | 51 |
1 files changed, 28 insertions, 23 deletions
diff --git a/libavutil/float2half.h b/libavutil/float2half.h index d6aaab8278..3548aa1d45 100644 --- a/libavutil/float2half.h +++ b/libavutil/float2half.h @@ -21,45 +21,50 @@ #include <stdint.h> -static void float2half_tables(uint16_t *basetable, uint8_t *shifttable) +typedef struct Float2HalfTables { + uint16_t basetable[512]; + uint8_t shifttable[512]; +} Float2HalfTables; + +static void init_float2half_tables(Float2HalfTables *t) { for (int i = 0; i < 256; i++) { int e = i - 127; if (e < -24) { // Very small numbers map to zero - basetable[i|0x000] = 0x0000; - basetable[i|0x100] = 0x8000; - shifttable[i|0x000] = 24; - shifttable[i|0x100] = 24; + t->basetable[i|0x000] = 0x0000; + t->basetable[i|0x100] = 0x8000; + t->shifttable[i|0x000] = 24; + t->shifttable[i|0x100] = 24; } else if (e < -14) { // Small numbers map to denorms - basetable[i|0x000] = (0x0400>>(-e-14)); - basetable[i|0x100] = (0x0400>>(-e-14)) | 0x8000; - shifttable[i|0x000] = -e-1; - shifttable[i|0x100] = -e-1; + t->basetable[i|0x000] = (0x0400>>(-e-14)); + t->basetable[i|0x100] = (0x0400>>(-e-14)) | 0x8000; + t->shifttable[i|0x000] = -e-1; + t->shifttable[i|0x100] = -e-1; } else if (e <= 15) { // Normal numbers just lose precision - basetable[i|0x000] = ((e + 15) << 10); - basetable[i|0x100] = ((e + 15) << 10) | 0x8000; - shifttable[i|0x000] = 13; - shifttable[i|0x100] = 13; + t->basetable[i|0x000] = ((e + 15) << 10); + t->basetable[i|0x100] = ((e + 15) << 10) | 0x8000; + t->shifttable[i|0x000] = 13; + t->shifttable[i|0x100] = 13; } else if (e < 128) { // Large numbers map to Infinity - basetable[i|0x000] = 0x7C00; - basetable[i|0x100] = 0xFC00; - shifttable[i|0x000] = 24; - shifttable[i|0x100] = 24; + t->basetable[i|0x000] = 0x7C00; + t->basetable[i|0x100] = 0xFC00; + t->shifttable[i|0x000] = 24; + t->shifttable[i|0x100] = 24; } else { // Infinity and NaN's stay Infinity and NaN's - basetable[i|0x000] = 0x7C00; - basetable[i|0x100] = 0xFC00; - shifttable[i|0x000] = 13; - shifttable[i|0x100] = 13; + t->basetable[i|0x000] = 0x7C00; + t->basetable[i|0x100] = 0xFC00; + t->shifttable[i|0x000] = 13; + t->shifttable[i|0x100] = 13; } } } -static uint16_t float2half(uint32_t f, uint16_t *basetable, uint8_t *shifttable) +static uint16_t float2half(uint32_t f, const Float2HalfTables *t) { uint16_t h; - h = basetable[(f >> 23) & 0x1ff] + ((f & 0x007fffff) >> shifttable[(f >> 23) & 0x1ff]); + h = t->basetable[(f >> 23) & 0x1ff] + ((f & 0x007fffff) >> t->shifttable[(f >> 23) & 0x1ff]); return h; } |