From: Fiona Glaser <fiona@x264.com>
Date: Mon, 30 Mar 2009 01:27:32 +0000 (-0700)
Subject: Shave one instruction off CABAC encode_decision
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=291b6ab1cb56c15a0169312b1c7ee8be7a1b594b;p=libx264

Shave one instruction off CABAC encode_decision
range_lps>>6 ranges from 4-7, so (range_lps>>6)-4 == (range_lps>>6) & 3
---

diff --git a/common/cabac.c b/common/cabac.c
index 7a2e94dd..65d143f5 100644
--- a/common/cabac.c
+++ b/common/cabac.c
@@ -861,7 +861,7 @@ static inline void x264_cabac_encode_renorm( x264_cabac_t *cb )
 void x264_cabac_encode_decision_c( x264_cabac_t *cb, int i_ctx, int b )
 {
     int i_state = cb->state[i_ctx];
-    int i_range_lps = x264_cabac_range_lps[i_state][(cb->i_range>>6)&0x03];
+    int i_range_lps = x264_cabac_range_lps[i_state][(cb->i_range>>6)-4];
     cb->i_range -= i_range_lps;
     if( b != (i_state >> 6) )
     {
diff --git a/common/x86/cabac-a.asm b/common/x86/cabac-a.asm
index b5840fc2..32d4a741 100644
--- a/common/x86/cabac-a.asm
+++ b/common/x86/cabac-a.asm
@@ -76,8 +76,7 @@ cglobal x264_cabac_encode_decision_asm, 0,7
     movzx t3d, byte [t0+cb.state+t1]
     mov   t4d, t5d
     shr   t5d, 6
-    and   t5d, 3
-    LOAD_GLOBAL t5d, x264_cabac_range_lps, t5, t3*4
+    LOAD_GLOBAL t5d, x264_cabac_range_lps-4, t5, t3*4
     sub   t4d, t5d
     mov   t6d, t3d
     shr   t6d, 6