[FFmpeg-devel] [PATCH] lavc/x86/videodsp: Drop MMX usage
Frank Plowman
post at frankplowman.com
Sat Nov 16 20:00:27 EET 2024
On 15/11/2024 20:55, Andreas Rheinhardt wrote:
> Frank Plowman:
>> Remove the MMX versions of these functions and modify the SSE
>> implementations to avoid using MMX registers.
>>
>> Signed-off-by: Frank Plowman <post at frankplowman.com>
>> ---
>> This wasn't wholly straightforward as the existing SSE implementation did
>> not only use SSE but rather a blend of SSE and MMX. I would appreciate
>> some review, as I am not particularly familiar with x86 assembly. Of
>> particular interest are the changes to {READ,WRITE}_NUM_BYTES. The new
>> implementation does not make economic use of the XMM registers like the
>> old one did, but it still does not exhaust them -- was this more of a
>> concern when this was originally written?
>> ---
>> libavcodec/x86/videodsp.asm | 63 ++++++----------------
>> libavcodec/x86/videodsp_init.c | 99 +++++++++++++++++-----------------
>> 2 files changed, 65 insertions(+), 97 deletions(-)
>>
>> diff --git a/libavcodec/x86/videodsp.asm b/libavcodec/x86/videodsp.asm
>> index 3cc07878d3..20dcd3e2b9 100644
>> --- a/libavcodec/x86/videodsp.asm
>> +++ b/libavcodec/x86/videodsp.asm
>> @@ -123,54 +123,43 @@ hvar_fn
>> ; - if (%2 & 8) fills 8 bytes into xmm$next
>> ; - if (%2 & 4) fills 4 bytes into xmm$next
>> ; - if (%2 & 3) fills 1, 2 or 4 bytes in eax
>> -; on mmx, - fills mm0-7 for consecutive sets of 8 pixels
>> -; - if (%2 & 4) fills 4 bytes into mm$next
>> -; - if (%2 & 3) fills 1, 2 or 4 bytes in eax
>> ; writing data out is in the same way
>> %macro READ_NUM_BYTES 2
>> %assign %%off 0 ; offset in source buffer
>> -%assign %%mmx_idx 0 ; mmx register index
>> %assign %%xmm_idx 0 ; xmm register index
>>
>> %rep %2/mmsize
>> -%if mmsize == 16
>> movu xmm %+ %%xmm_idx, [srcq+%%off]
>> %assign %%xmm_idx %%xmm_idx+1
>> -%else ; mmx
>> - movu mm %+ %%mmx_idx, [srcq+%%off]
>> -%assign %%mmx_idx %%mmx_idx+1
>> -%endif
>> %assign %%off %%off+mmsize
>> %endrep ; %2/mmsize
>>
>> -%if mmsize == 16
>> %if (%2-%%off) >= 8
>> %if %2 > 16 && (%2-%%off) > 8
>> movu xmm %+ %%xmm_idx, [srcq+%2-16]
>> %assign %%xmm_idx %%xmm_idx+1
>> %assign %%off %2
>> %else
>> - movq mm %+ %%mmx_idx, [srcq+%%off]
>> -%assign %%mmx_idx %%mmx_idx+1
>> + movq xmm %+ %%xmm_idx, [srcq+%%off]
>> +%assign %%xmm_idx %%xmm_idx+1
>> %assign %%off %%off+8
>> %endif
>> %endif ; (%2-%%off) >= 8
>> -%endif
>>
>> %if (%2-%%off) >= 4
>> %if %2 > 8 && (%2-%%off) > 4
>> - movq mm %+ %%mmx_idx, [srcq+%2-8]
>> + movq xmm %+ %%xmm_idx, [srcq+%2-8]
>> %assign %%off %2
>> %else
>> - movd mm %+ %%mmx_idx, [srcq+%%off]
>> + movd xmm %+ %%xmm_idx, [srcq+%%off]
>> %assign %%off %%off+4
>> %endif
>> -%assign %%mmx_idx %%mmx_idx+1
>> +%assign %%xmm_idx %%xmm_idx+1
>> %endif ; (%2-%%off) >= 4
>>
>> %if (%2-%%off) >= 1
>> %if %2 >= 4
>> - movd mm %+ %%mmx_idx, [srcq+%2-4]
>> + movd xmm %+ %%xmm_idx, [srcq+%2-4]
>> %elif (%2-%%off) == 1
>> mov valb, [srcq+%2-1]
>> %elif (%2-%%off) == 2
>> @@ -185,48 +174,40 @@ hvar_fn
>>
>> %macro WRITE_NUM_BYTES 2
>> %assign %%off 0 ; offset in destination buffer
>> -%assign %%mmx_idx 0 ; mmx register index
>> %assign %%xmm_idx 0 ; xmm register index
>>
>> %rep %2/mmsize
>> -%if mmsize == 16
>> movu [dstq+%%off], xmm %+ %%xmm_idx
>> %assign %%xmm_idx %%xmm_idx+1
>> -%else ; mmx
>> - movu [dstq+%%off], mm %+ %%mmx_idx
>> -%assign %%mmx_idx %%mmx_idx+1
>> -%endif
>> %assign %%off %%off+mmsize
>> %endrep ; %2/mmsize
>>
>> -%if mmsize == 16
>> %if (%2-%%off) >= 8
>> %if %2 > 16 && (%2-%%off) > 8
>> movu [dstq+%2-16], xmm %+ %%xmm_idx
>> %assign %%xmm_idx %%xmm_idx+1
>> %assign %%off %2
>> %else
>> - movq [dstq+%%off], mm %+ %%mmx_idx
>> -%assign %%mmx_idx %%mmx_idx+1
>> + movq [dstq+%%off], xmm %+ %%xmm_idx
>> +%assign %%xmm_idx %%xmm_idx+1
>> %assign %%off %%off+8
>> %endif
>> %endif ; (%2-%%off) >= 8
>> -%endif
>>
>> %if (%2-%%off) >= 4
>> %if %2 > 8 && (%2-%%off) > 4
>> - movq [dstq+%2-8], mm %+ %%mmx_idx
>> + movq [dstq+%2-8], xmm %+ %%xmm_idx
>> %assign %%off %2
>> %else
>> - movd [dstq+%%off], mm %+ %%mmx_idx
>> + movd [dstq+%%off], xmm %+ %%xmm_idx
>> %assign %%off %%off+4
>> %endif
>> -%assign %%mmx_idx %%mmx_idx+1
>> +%assign %%xmm_idx %%xmm_idx+1
>> %endif ; (%2-%%off) >= 4
>>
>> %if (%2-%%off) >= 1
>> %if %2 >= 4
>> - movd [dstq+%2-4], mm %+ %%mmx_idx
>> + movd [dstq+%2-4], xmm %+ %%xmm_idx
>> %elif (%2-%%off) == 1
>> mov [dstq+%2-1], valb
>> %elif (%2-%%off) == 2
>> @@ -318,11 +299,8 @@ cglobal emu_edge_vfix %+ %%n, 1, 5, 1, dst, src, start_y, end_y, bh
>> %endrep ; 1+%2-%1
>> %endmacro ; VERTICAL_EXTEND
>>
>> -INIT_MMX mmx
>> -VERTICAL_EXTEND 1, 15
>> -
>> -INIT_XMM sse
>> -VERTICAL_EXTEND 16, 22
>> +INIT_XMM sse2
>> +VERTICAL_EXTEND 1, 22
>>
>> ; left/right (horizontal) fast extend functions
>> ; these are essentially identical to the vertical extend ones above,
>> @@ -337,11 +315,7 @@ VERTICAL_EXTEND 16, 22
>> imul vald, 0x01010101
>> %if %1 >= 8
>> movd m0, vald
>> -%if mmsize == 16
>> pshufd m0, m0, q0000
>> -%else
>> - punpckldq m0, m0
>> -%endif ; mmsize == 16
>> %endif ; %1 > 16
>> %endif ; avx2
>> %endmacro ; READ_V_PIXEL
>> @@ -356,7 +330,6 @@ VERTICAL_EXTEND 16, 22
>> %assign %%off %%off+mmsize
>> %endrep ; %1/mmsize
>>
>> -%if mmsize == 16
>> %if %1-%%off >= 8
>> %if %1 > 16 && %1-%%off > 8
>> movu [%2+%1-16], m0
>> @@ -366,7 +339,6 @@ VERTICAL_EXTEND 16, 22
>> %assign %%off %%off+8
>> %endif
>> %endif ; %1-%%off >= 8
>> -%endif ; mmsize == 16
>>
>> %if %1-%%off >= 4
>> %if %1 > 8 && %1-%%off > 4
>> @@ -415,18 +387,15 @@ cglobal emu_edge_hfix %+ %%n, 4, 5, 1, dst, dst_stride, start_x, bh, val
>> %endrep ; 1+(%2-%1)/2
>> %endmacro ; H_EXTEND
>>
>> -INIT_MMX mmx
>> -H_EXTEND 2, 14
>> -
>> INIT_XMM sse2
>> -H_EXTEND 16, 22
>> +H_EXTEND 2, 22
>>
>> %if HAVE_AVX2_EXTERNAL
>> INIT_XMM avx2
>> H_EXTEND 8, 22
>> %endif
>>
>> -INIT_MMX mmxext
>> +INIT_XMM sse2
>> cglobal prefetch, 3, 3, 0, buf, stride, h
>> .loop:
>> prefetcht0 [bufq]
>> diff --git a/libavcodec/x86/videodsp_init.c b/libavcodec/x86/videodsp_init.c
>> index ae9db95624..376eec9c23 100644
>> --- a/libavcodec/x86/videodsp_init.c
>> +++ b/libavcodec/x86/videodsp_init.c
>> @@ -37,37 +37,37 @@ typedef void emu_edge_vvar_func(uint8_t *dst, x86_reg dst_stride,
>> x86_reg start_y, x86_reg end_y, x86_reg bh,
>> x86_reg w);
>>
>> -extern emu_edge_vfix_func ff_emu_edge_vfix1_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix2_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix3_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix4_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix5_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix6_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix7_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix8_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix9_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix10_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix11_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix12_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix13_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix14_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix15_mmx;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix16_sse;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix17_sse;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix18_sse;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix19_sse;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix20_sse;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix21_sse;
>> -extern emu_edge_vfix_func ff_emu_edge_vfix22_sse;
>> -static emu_edge_vfix_func * const vfixtbl_sse[22] = {
>> - ff_emu_edge_vfix1_mmx, ff_emu_edge_vfix2_mmx, ff_emu_edge_vfix3_mmx,
>> - ff_emu_edge_vfix4_mmx, ff_emu_edge_vfix5_mmx, ff_emu_edge_vfix6_mmx,
>> - ff_emu_edge_vfix7_mmx, ff_emu_edge_vfix8_mmx, ff_emu_edge_vfix9_mmx,
>> - ff_emu_edge_vfix10_mmx, ff_emu_edge_vfix11_mmx, ff_emu_edge_vfix12_mmx,
>> - ff_emu_edge_vfix13_mmx, ff_emu_edge_vfix14_mmx, ff_emu_edge_vfix15_mmx,
>> - ff_emu_edge_vfix16_sse, ff_emu_edge_vfix17_sse, ff_emu_edge_vfix18_sse,
>> - ff_emu_edge_vfix19_sse, ff_emu_edge_vfix20_sse, ff_emu_edge_vfix21_sse,
>> - ff_emu_edge_vfix22_sse
>> +extern emu_edge_vfix_func ff_emu_edge_vfix1_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix2_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix3_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix4_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix5_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix6_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix7_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix8_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix9_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix10_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix11_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix12_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix13_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix14_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix15_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix16_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix17_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix18_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix19_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix20_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix21_sse2;
>> +extern emu_edge_vfix_func ff_emu_edge_vfix22_sse2;
>> +static emu_edge_vfix_func * const vfixtbl_sse2[22] = {
>> + ff_emu_edge_vfix1_sse2, ff_emu_edge_vfix2_sse2, ff_emu_edge_vfix3_sse2,
>> + ff_emu_edge_vfix4_sse2, ff_emu_edge_vfix5_sse2, ff_emu_edge_vfix6_sse2,
>> + ff_emu_edge_vfix7_sse2, ff_emu_edge_vfix8_sse2, ff_emu_edge_vfix9_sse2,
>> + ff_emu_edge_vfix10_sse2, ff_emu_edge_vfix11_sse2, ff_emu_edge_vfix12_sse2,
>> + ff_emu_edge_vfix13_sse2, ff_emu_edge_vfix14_sse2, ff_emu_edge_vfix15_sse2,
>> + ff_emu_edge_vfix16_sse2, ff_emu_edge_vfix17_sse2, ff_emu_edge_vfix18_sse2,
>> + ff_emu_edge_vfix19_sse2, ff_emu_edge_vfix20_sse2, ff_emu_edge_vfix21_sse2,
>> + ff_emu_edge_vfix22_sse2
>> };
>> extern emu_edge_vvar_func ff_emu_edge_vvar_sse;
>>
>> @@ -76,21 +76,21 @@ typedef void emu_edge_hfix_func(uint8_t *dst, x86_reg dst_stride,
>> typedef void emu_edge_hvar_func(uint8_t *dst, x86_reg dst_stride,
>> x86_reg start_x, x86_reg n_words, x86_reg bh);
>>
>> -extern emu_edge_hfix_func ff_emu_edge_hfix2_mmx;
>> -extern emu_edge_hfix_func ff_emu_edge_hfix4_mmx;
>> -extern emu_edge_hfix_func ff_emu_edge_hfix6_mmx;
>> -extern emu_edge_hfix_func ff_emu_edge_hfix8_mmx;
>> -extern emu_edge_hfix_func ff_emu_edge_hfix10_mmx;
>> -extern emu_edge_hfix_func ff_emu_edge_hfix12_mmx;
>> -extern emu_edge_hfix_func ff_emu_edge_hfix14_mmx;
>> +extern emu_edge_hfix_func ff_emu_edge_hfix2_sse2;
>> +extern emu_edge_hfix_func ff_emu_edge_hfix4_sse2;
>> +extern emu_edge_hfix_func ff_emu_edge_hfix6_sse2;
>> +extern emu_edge_hfix_func ff_emu_edge_hfix8_sse2;
>> +extern emu_edge_hfix_func ff_emu_edge_hfix10_sse2;
>> +extern emu_edge_hfix_func ff_emu_edge_hfix12_sse2;
>> +extern emu_edge_hfix_func ff_emu_edge_hfix14_sse2;
>> extern emu_edge_hfix_func ff_emu_edge_hfix16_sse2;
>> extern emu_edge_hfix_func ff_emu_edge_hfix18_sse2;
>> extern emu_edge_hfix_func ff_emu_edge_hfix20_sse2;
>> extern emu_edge_hfix_func ff_emu_edge_hfix22_sse2;
>> static emu_edge_hfix_func * const hfixtbl_sse2[11] = {
>> - ff_emu_edge_hfix2_mmx, ff_emu_edge_hfix4_mmx, ff_emu_edge_hfix6_mmx,
>> - ff_emu_edge_hfix8_mmx, ff_emu_edge_hfix10_mmx, ff_emu_edge_hfix12_mmx,
>> - ff_emu_edge_hfix14_mmx, ff_emu_edge_hfix16_sse2, ff_emu_edge_hfix18_sse2,
>> + ff_emu_edge_hfix2_sse2, ff_emu_edge_hfix4_sse2, ff_emu_edge_hfix6_sse2,
>> + ff_emu_edge_hfix8_sse2, ff_emu_edge_hfix10_sse2, ff_emu_edge_hfix12_sse2,
>> + ff_emu_edge_hfix14_sse2, ff_emu_edge_hfix16_sse2, ff_emu_edge_hfix18_sse2,
>> ff_emu_edge_hfix20_sse2, ff_emu_edge_hfix22_sse2
>> };
>> extern emu_edge_hvar_func ff_emu_edge_hvar_sse2;
>> @@ -104,7 +104,7 @@ extern emu_edge_hfix_func ff_emu_edge_hfix18_avx2;
>> extern emu_edge_hfix_func ff_emu_edge_hfix20_avx2;
>> extern emu_edge_hfix_func ff_emu_edge_hfix22_avx2;
>> static emu_edge_hfix_func * const hfixtbl_avx2[11] = {
>> - ff_emu_edge_hfix2_mmx, ff_emu_edge_hfix4_mmx, ff_emu_edge_hfix6_mmx,
>> + ff_emu_edge_hfix2_sse2, ff_emu_edge_hfix4_sse2, ff_emu_edge_hfix6_sse2,
>> ff_emu_edge_hfix8_avx2, ff_emu_edge_hfix10_avx2, ff_emu_edge_hfix12_avx2,
>> ff_emu_edge_hfix14_avx2, ff_emu_edge_hfix16_avx2, ff_emu_edge_hfix18_avx2,
>> ff_emu_edge_hfix20_avx2, ff_emu_edge_hfix22_avx2
>> @@ -196,7 +196,7 @@ static av_noinline void emulated_edge_mc_sse2(uint8_t *buf, const uint8_t *src,
>> int h)
>> {
>> emulated_edge_mc(buf, src, buf_stride, src_stride, block_w, block_h,
>> - src_x, src_y, w, h, vfixtbl_sse, &ff_emu_edge_vvar_sse,
>> + src_x, src_y, w, h, vfixtbl_sse2, &ff_emu_edge_vvar_sse,
>> hfixtbl_sse2, &ff_emu_edge_hvar_sse2);
>> }
>>
>> @@ -209,24 +209,23 @@ static av_noinline void emulated_edge_mc_avx2(uint8_t *buf, const uint8_t *src,
>> int h)
>> {
>> emulated_edge_mc(buf, src, buf_stride, src_stride, block_w, block_h,
>> - src_x, src_y, w, h, vfixtbl_sse, &ff_emu_edge_vvar_sse,
>> + src_x, src_y, w, h, vfixtbl_sse2, &ff_emu_edge_vvar_sse,
>> hfixtbl_avx2, &ff_emu_edge_hvar_avx2);
>> }
>> #endif /* HAVE_AVX2_EXTERNAL */
>> #endif /* HAVE_X86ASM */
>>
>> -void ff_prefetch_mmxext(const uint8_t *buf, ptrdiff_t stride, int h);
>> +void ff_prefetch_sse2(const uint8_t *buf, ptrdiff_t stride, int h);
>>
>> av_cold void ff_videodsp_init_x86(VideoDSPContext *ctx, int bpc)
>> {
>> #if HAVE_X86ASM
>> int cpu_flags = av_get_cpu_flags();
>>
>> - if (EXTERNAL_MMXEXT(cpu_flags)) {
>> - ctx->prefetch = ff_prefetch_mmxext;
>> - }
>> - if (EXTERNAL_SSE2(cpu_flags) && bpc <= 8) {
>> - ctx->emulated_edge_mc = emulated_edge_mc_sse2;
>> + if (EXTERNAL_SSE2(cpu_flags)) {
>> + ctx->prefetch = ff_prefetch_sse2;
>> + if (bpc <= 8)
>> + ctx->emulated_edge_mc = emulated_edge_mc_sse2;
>> }
>> #if HAVE_AVX2_EXTERNAL
>> if (EXTERNAL_AVX2(cpu_flags) && bpc <= 8) {
>
> Why did you change prefetch to declare an SSE2 requirement?
>
> - Andreas
No good reason. I've reverted the changes to prefetch in v2.
--
Frank
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