optimization: move code for non-zero crc16_align out of the way since it is a rare...

diff --git a/src/libFLAC/ia32/bitreader_asm.nasm b/src/libFLAC/ia32/bitreader_asm.nasm
index 1f976e6..6decd34 100644 (file)
--- a/src/libFLAC/ia32/bitreader_asm.nasm
+++ b/src/libFLAC/ia32/bitreader_asm.nasm
@@ -148,13 +148,7 @@ cident FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap
        ;; edi          unsigned FLAC__crc16_table[]
        ;; ebp          br
        test    ecx, ecx                ;               switch(br->crc16_align) ...
-       jz      .c0b0                   ;               [br->crc16_align is 0 the vast majority of the time so we optimize the common case]
-       cmp     ecx, 8
-       je      .c0b1
-       shr     edx, 16
-       cmp     ecx, 16
-       je      .c0b2
-       jmp     .c0b3
+       jnz     .c0b4                   ;               [br->crc16_align is 0 the vast majority of the time so we optimize the common case]
 .c0b0: xor     dl, ah                  ;               dl <- (crc>>8)^(word>>24)
        movzx   ebx, dl
        mov     cx, [ebx*4 + edi]       ;               cx <- FLAC__crc16_table[(crc>>8)^(word>>24)]
@@ -177,7 +171,6 @@ cident FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap
        shl     ax, 8                   ;               ax <- (crc<<8)
        xor     ax, cx                  ;               crc <- ax <- (crc<<8) ^ FLAC__crc16_table[(crc>>8)^(word&0xff)]
        mov     [ebp + 24], eax         ;               br->read_crc <- crc
-       mov     [ebp + 28], dword 0     ;               br->crc16_align <- 0
        pop     ecx
        pop     edi
 
@@ -185,6 +178,25 @@ cident FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap
        xor     ecx, ecx                ;           cbits = 0;
                                        ;         }
        jmp     near .break1            ;         goto break1;
+       ;; this section relocated out of the way for performance
+.c0b4:
+       mov     [ebp + 28], dword 0     ;               br->crc16_align <- 0
+       cmp     ecx, 8
+       je      .c0b1
+       shr     edx, 16
+       cmp     ecx, 16
+       je      .c0b2
+       jmp     .c0b3
+
+       ;; this section relocated out of the way for performance
+.c1b4:
+       mov     [ebp + 28], dword 0     ;               br->crc16_align <- 0
+       cmp     ecx, 8
+       je      .c1b1
+       shr     edx, 16
+       cmp     ecx, 16
+       je      .c1b2
+       jmp     .c1b3
 
 .c1_next2:                             ;       } else {
        ;; ecx          cbits
@@ -210,13 +222,7 @@ cident FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap
        ;; edi          unsigned FLAC__crc16_table[]
        ;; ebp          br
        test    ecx, ecx                ;               switch(br->crc16_align) ...
-       jz      .c1b0                   ;               [br->crc16_align is 0 the vast majority of the time so we optimize the common case]
-       cmp     ecx, 8
-       je      .c1b1
-       shr     edx, 16
-       cmp     ecx, 16
-       je      .c1b2
-       jmp     .c1b3
+       jnz     .c1b4                   ;               [br->crc16_align is 0 the vast majority of the time so we optimize the common case]
 .c1b0: xor     dl, ah                  ;               dl <- (crc>>8)^(word>>24)
        movzx   ebx, dl
        mov     cx, [ebx*4 + edi]       ;               cx <- FLAC__crc16_table[(crc>>8)^(word>>24)]
@@ -239,7 +245,6 @@ cident FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap
        shl     ax, 8                   ;               ax <- (crc<<8)
        xor     ax, cx                  ;               crc <- ax <- (crc<<8) ^ FLAC__crc16_table[(crc>>8)^(word&0xff)]
        mov     [ebp + 24], eax         ;               br->read_crc <- crc
-       mov     [ebp + 28], dword 0     ;               br->crc16_align <- 0
        pop     ecx
        pop     edi
 
@@ -428,13 +433,7 @@ cident FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap
        ;; edi          unsigned FLAC__crc16_table[]
        ;; ebp          br
        test    ecx, ecx                ;               switch(br->crc16_align) ...
-       jz      .c2b0                   ;               [br->crc16_align is 0 the vast majority of the time so we optimize the common case]
-       cmp     ecx, 8
-       je      .c2b1
-       shr     edx, 16
-       cmp     ecx, 16
-       je      .c2b2
-       jmp     .c2b3
+       jnz     .c2b4                   ;               [br->crc16_align is 0 the vast majority of the time so we optimize the common case]
 .c2b0: xor     dl, ah                  ;               dl <- (crc>>8)^(word>>24)
        movzx   ebx, dl
        mov     cx, [ebx*4 + edi]       ;               cx <- FLAC__crc16_table[(crc>>8)^(word>>24)]
@@ -457,7 +456,6 @@ cident FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap
        shl     ax, 8                   ;               ax <- (crc<<8)
        xor     ax, cx                  ;               crc <- ax <- (crc<<8) ^ FLAC__crc16_table[(crc>>8)^(word&0xff)]
        mov     [ebp + 24], eax         ;               br->read_crc <- crc
-       mov     [ebp + 28], dword 0     ;               br->crc16_align <- 0
        pop     eax
        pop     ecx
        pop     ebx
@@ -473,6 +471,17 @@ cident FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap
        shld    edi, eax, cl
                                        ;         }
        jmp     .break2                 ;         goto break2;
+
+       ;; this section relocated out of the way for performance
+.c2b4:
+       mov     [ebp + 28], dword 0     ;               br->crc16_align <- 0
+       cmp     ecx, 8
+       je      .c2b1
+       shr     edx, 16
+       cmp     ecx, 16
+       je      .c2b2
+       jmp     .c2b3
+
 .c2_next3:                             ;       } else {
        mov     ecx, ebx                ;         cbits = parameter;
                                        ;         uval <<= cbits;