From cb1479faca0f41f575d680784f66b7d519a24b14 Mon Sep 17 00:00:00 2001 From: Evgeny Pavlov Date: Mon, 31 Jul 2023 13:26:16 +0200 Subject: [PATCH] avfilter/vf_ssim: Fix x86 assembly code for SSIM calculation This commit fixes bug #10495 The code had several bugs related to post-loop compensation code: - test assembly instruction performs bitwise AND operation and generate flags used by jz branch instruction. Wrong test condition leads to incorrect branching - Incorrect compensation code for some branches Signed-off-by: Evgeny Pavlov --- libavfilter/x86/vf_ssim.asm | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) diff --git a/libavfilter/x86/vf_ssim.asm b/libavfilter/x86/vf_ssim.asm index 78809305de..e3e0c8104b 100644 --- a/libavfilter/x86/vf_ssim.asm +++ b/libavfilter/x86/vf_ssim.asm @@ -228,25 +228,22 @@ cglobal ssim_end_line, 3, 3, 7, sum0, sum1, w ; subpd the ones we added too much test wd, wd - jz .end + jz .end add wd, 4 - test wd, 3 - jz .skip3 - test wd, 2 - jz .skip2 - test wd, 1 - jz .skip1 -.skip3: + cmp wd, 1 + jz .skip3 + cmp wd, 2 + jz .skip2 +.skip1: ; 3 valid => skip 1 invalid psrldq m5, 8 subpd m6, m5 - jmp .end -.skip2: - psrldq m5, 8 + jmp .end +.skip2: ; 2 valid => skip 2 invalid subpd m6, m5 + jmp .end +.skip3: ; 1 valid => skip 3 invalid + psrldq m3, 8 subpd m0, m3 - jmp .end -.skip1: - psrldq m3, 16 subpd m6, m5 .end: