Index: celt/entcode.c |
diff --git a/celt/entcode.c b/celt/entcode.c |
index fa5d7c7c2c92d7c30cbd455b7825a29641a8d30a..70f32016ecee977045d9f05da7c7fa16346d4142 100644 |
--- a/celt/entcode.c |
+++ b/celt/entcode.c |
@@ -62,6 +62,27 @@ int ec_ilog(opus_uint32 _v){ |
} |
#endif |
+#if 1 |
+/* This is a faster version of ec_tell_frac() that takes advantage |
+ of the low (1/8 bit) resolution to use just a linear function |
+ followed by a lookup to determine the exact transition thresholds. */ |
+opus_uint32 ec_tell_frac(ec_ctx *_this){ |
+ static const unsigned correction[8] = |
+ {35733, 38967, 42495, 46340, |
+ 50535, 55109, 60097, 65535}; |
+ opus_uint32 nbits; |
+ opus_uint32 r; |
+ int l; |
+ unsigned b; |
+ nbits=_this->nbits_total<<BITRES; |
+ l=EC_ILOG(_this->rng); |
+ r=_this->rng>>(l-16); |
+ b = (r>>12)-8; |
+ b += r>correction[b]; |
+ l = (l<<3)+b; |
+ return nbits-l; |
+} |
+#else |
opus_uint32 ec_tell_frac(ec_ctx *_this){ |
opus_uint32 nbits; |
opus_uint32 r; |
@@ -91,3 +112,42 @@ opus_uint32 ec_tell_frac(ec_ctx *_this){ |
} |
return nbits-l; |
} |
+#endif |
+ |
+#ifdef USE_SMALL_DIV_TABLE |
+/* Result of 2^32/(2*i+1), except for i=0. */ |
+const opus_uint32 SMALL_DIV_TABLE[129] = { |
+ 0xFFFFFFFF, 0x55555555, 0x33333333, 0x24924924, |
+ 0x1C71C71C, 0x1745D174, 0x13B13B13, 0x11111111, |
+ 0x0F0F0F0F, 0x0D79435E, 0x0C30C30C, 0x0B21642C, |
+ 0x0A3D70A3, 0x097B425E, 0x08D3DCB0, 0x08421084, |
+ 0x07C1F07C, 0x07507507, 0x06EB3E45, 0x06906906, |
+ 0x063E7063, 0x05F417D0, 0x05B05B05, 0x0572620A, |
+ 0x05397829, 0x05050505, 0x04D4873E, 0x04A7904A, |
+ 0x047DC11F, 0x0456C797, 0x04325C53, 0x04104104, |
+ 0x03F03F03, 0x03D22635, 0x03B5CC0E, 0x039B0AD1, |
+ 0x0381C0E0, 0x0369D036, 0x03531DEC, 0x033D91D2, |
+ 0x0329161F, 0x03159721, 0x03030303, 0x02F14990, |
+ 0x02E05C0B, 0x02D02D02, 0x02C0B02C, 0x02B1DA46, |
+ 0x02A3A0FD, 0x0295FAD4, 0x0288DF0C, 0x027C4597, |
+ 0x02702702, 0x02647C69, 0x02593F69, 0x024E6A17, |
+ 0x0243F6F0, 0x0239E0D5, 0x02302302, 0x0226B902, |
+ 0x021D9EAD, 0x0214D021, 0x020C49BA, 0x02040810, |
+ 0x01FC07F0, 0x01F44659, 0x01ECC07B, 0x01E573AC, |
+ 0x01DE5D6E, 0x01D77B65, 0x01D0CB58, 0x01CA4B30, |
+ 0x01C3F8F0, 0x01BDD2B8, 0x01B7D6C3, 0x01B20364, |
+ 0x01AC5701, 0x01A6D01A, 0x01A16D3F, 0x019C2D14, |
+ 0x01970E4F, 0x01920FB4, 0x018D3018, 0x01886E5F, |
+ 0x0183C977, 0x017F405F, 0x017AD220, 0x01767DCE, |
+ 0x01724287, 0x016E1F76, 0x016A13CD, 0x01661EC6, |
+ 0x01623FA7, 0x015E75BB, 0x015AC056, 0x01571ED3, |
+ 0x01539094, 0x01501501, 0x014CAB88, 0x0149539E, |
+ 0x01460CBC, 0x0142D662, 0x013FB013, 0x013C995A, |
+ 0x013991C2, 0x013698DF, 0x0133AE45, 0x0130D190, |
+ 0x012E025C, 0x012B404A, 0x01288B01, 0x0125E227, |
+ 0x01234567, 0x0120B470, 0x011E2EF3, 0x011BB4A4, |
+ 0x01194538, 0x0116E068, 0x011485F0, 0x0112358E, |
+ 0x010FEF01, 0x010DB20A, 0x010B7E6E, 0x010953F3, |
+ 0x01073260, 0x0105197F, 0x0103091B, 0x01010101 |
+}; |
+#endif |