Ping?

Not including EMMS causes the FPU to become unusable (as the IE and SF bits are 
set in the status word). This breaks code which, for instance, calls fmod() and 
is compiled by GCC with the -O3 flag enabled. In that scenario, GCC implements 
fmod using the FPREM FPU instruction, but because FPU is in the invalid state 
at that point, the result is NaN.

This must to breaking other code using FPU also. The original code with inline 
assembly used EMMS at the end.
________________________________
From: Mario Hros <k3x-de...@outlook.com>
Sent: Wednesday, June 5, 2024 7:35 PM
To: ffmpeg-devel@ffmpeg.org <ffmpeg-devel@ffmpeg.org>
Cc: Mario Hros <k3x-de...@outlook.com>
Subject: [PATCH] libswscale/x86/yuv2rgb: Add missing EMMS

Previous rewrite from inline assembly into nasm (commit e934194) missed the 
required EMMS instruction to bring the x87 FPU back into usable state.

Signed-off-by: Mario Hros <k3x-de...@outlook.com>
---
 libswscale/x86/yuv_2_rgb.asm | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libswscale/x86/yuv_2_rgb.asm b/libswscale/x86/yuv_2_rgb.asm
index e3470fd9ad..7a247797e4 100644
--- a/libswscale/x86/yuv_2_rgb.asm
+++ b/libswscale/x86/yuv_2_rgb.asm
@@ -353,6 +353,7 @@ cglobal %1_420_%2%3, GPR_num, GPR_num, reg_num, parameters
 add imageq, 8 * depth * time_num
 add indexq, 4 * time_num
 js .loop0
+emms

 RET

--
2.39.3 (Apple Git-146)

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".

Reply via email to