cosmetic changes, comments, add tests for data_len == 0

diff --git a/src/libFLAC/i386/lpc_asm.s b/src/libFLAC/i386/lpc_asm.s
index 9a47ea1..cdd192d 100644 (file)
--- a/src/libFLAC/i386/lpc_asm.s
+++ b/src/libFLAC/i386/lpc_asm.s
@@ -57,10 +57,10 @@ cglobal FLAC__lpc_restore_signal_asm_i386_mmx
        ALIGN 16
 cident FLAC__lpc_compute_autocorrelation_asm_i386:
 
-       ; esp + 20 == data[]
-       ; esp + 24 == data_len
-       ; esp + 28 == lag
        ; esp + 32 == autoc[]
+       ; esp + 28 == lag
+       ; esp + 24 == data_len
+       ; esp + 20 == data[]
 
        push    ebp
        push    ebx
@@ -208,10 +208,10 @@ cident FLAC__lpc_compute_autocorrelation_asm_i386:
        ALIGN 16
 cident FLAC__lpc_compute_autocorrelation_asm_i386_sse:
 
-       ; esp + 4 == data[]
-       ; esp + 8 == data_len
-       ; esp + 12 == lag
        ; esp + 16 == autoc[]
+       ; esp + 12 == lag
+       ; esp + 8 == data_len
+       ; esp + 4 == data[]
 
        ;       for(coeff = 0; coeff < lag; coeff++)
        ;               autoc[coeff] = 0.0;
@@ -293,19 +293,21 @@ cident FLAC__lpc_compute_residual_from_qlp_coefficients_asm_i386:
        push    esi
        push    edi
 
-       mov     esi, [esp + 20]
-       mov     edi, [esp + 40]
-       mov     eax, [esp + 32]
-       mov     ebx, [esp + 24]
+       mov     esi, [esp + 20]                 ; esi = data[]
+       mov     edi, [esp + 40]                 ; edi = residual[]
+       mov     eax, [esp + 32]                 ; eax = order
+       mov     ebx, [esp + 24]                 ; ebx = data_len
 
+       test    ebx, ebx
+       jz      .end                            ; do nothing if data_len == 0
 .begin:
        cmp     eax, byte 1
        jg      short .i_1more
 
        mov     ecx, [esp + 28]
-       mov     edx, [ecx]
-       mov     eax, [esi - 4]
-       mov     cl, [esp + 36]
+       mov     edx, [ecx]                      ; edx = qlp_coeff[0]
+       mov     eax, [esi - 4]                  ; eax = data[-1]
+       mov     cl, [esp + 36]                  ; cl = lp_quantization
        ALIGN   16
 .i_1_loop_i:
        imul    eax, edx
@@ -322,7 +324,7 @@ cident FLAC__lpc_compute_residual_from_qlp_coefficients_asm_i386:
        jmp     .end
 
 .i_1more:
-       cmp     eax, byte 32            ; for order <= 32 there is a faster routine
+       cmp     eax, byte 32                    ; for order <= 32 there is a faster routine
        jbe     short .i_32
 
        ; This version is here just for completeness, since FLAC__MAX_LPC_ORDER == 32
@@ -361,7 +363,7 @@ cident FLAC__lpc_compute_residual_from_qlp_coefficients_asm_i386:
        neg     eax
        lea     edx, [eax + eax * 8 + .jumper_0]
        inc     edx
-       mov     eax, [esp + 28]
+       mov     eax, [esp + 28]                 ; eax = qlp_coeff[]
        xor     ebp, ebp
        jmp     edx
 
@@ -499,17 +501,19 @@ cident FLAC__lpc_compute_residual_from_qlp_coefficients_asm_i386_mmx:
        push    esi
        push    edi
 
-       mov     esi, [esp + 20]
-       mov     edi, [esp + 40]
-       mov     eax, [esp + 32]
-       mov     ebx, [esp + 24]
+       mov     esi, [esp + 20]                 ; esi = data[]
+       mov     edi, [esp + 40]                 ; edi = residual[]
+       mov     eax, [esp + 32]                 ; eax = order
+       mov     ebx, [esp + 24]                 ; ebx = data_len
 
+       test    ebx, ebx
+       jz      near .end                       ; do nothing if data_len == 0
        dec     ebx
        test    ebx, ebx
        jz      near .last_one
 
-       mov     edx, [esp + 28]
-       movd    mm6, [esp + 36]
+       mov     edx, [esp + 28]                 ; edx = qlp_coeff[]
+       movd    mm6, [esp + 36]                 ; mm6 = 0:lp_quantization
        mov     ebp, esp
 
        and     esp, 0xfffffff8
@@ -649,6 +653,7 @@ cident FLAC__lpc_compute_residual_from_qlp_coefficients_asm_i386_mmx:
        inc     ebx
        jnz     near FLAC__lpc_compute_residual_from_qlp_coefficients_asm_i386.begin
 
+.end:
        pop     edi
        pop     esi
        pop     ebx
@@ -685,10 +690,13 @@ cident FLAC__lpc_restore_signal_asm_i386:
        push    esi
        push    edi
 
-       mov     esi, [esp + 20]
-       mov     edi, [esp + 40]
-       mov     eax, [esp + 32]
-       mov     ebx, [esp + 24]
+       mov     esi, [esp + 20]                 ; esi = residual[]
+       mov     edi, [esp + 40]                 ; edi = data[]
+       mov     eax, [esp + 32]                 ; eax = order
+       mov     ebx, [esp + 24]                 ; ebx = data_len
+
+       test    ebx, ebx
+       jz      .end                            ; do nothing if data_len == 0
 
        cmp     eax, byte 1
        jg      short .x87_1more
@@ -711,7 +719,7 @@ cident FLAC__lpc_restore_signal_asm_i386:
        jmp     .end
 
 .x87_1more:
-       cmp     eax, byte 32            ; for order <= 32 there is a faster routine
+       cmp     eax, byte 32                    ; for order <= 32 there is a faster routine
        jbe     short .x87_32
 
        ; This version is here just for completeness, since FLAC__MAX_LPC_ORDER == 32
@@ -891,6 +899,9 @@ cident FLAC__lpc_restore_signal_asm_i386_mmx:
        mov     eax, [esp + 32]
        mov     ebx, [esp + 24]
 
+       test    ebx, ebx
+       jz      .end                            ; do nothing if data_len == 0
+
        mov     edx, [esp + 28]
        movd    mm6, [esp + 36]
        mov     ebp, esp
@@ -994,6 +1005,7 @@ cident FLAC__lpc_restore_signal_asm_i386_mmx:
        emms
        mov     esp, ebp
 
+.end:
        pop     edi
        pop     esi
        pop     ebx