DOS ain't dead - SSE instructions in DOS programs?

SSE instructions in DOS programs? (Developers)

posted by Rugxulo , Usono, 12.01.2019, 23:54

> > There was a problem that SSE
> > code of FFMPEG didn't work under DOS/DJGPP so I disabled all inline asm
> > code for SSE but I never went deep into it if there's some workaround.
>
> If e.g. the library for ffmpeg expects the stack aligned, but some code
> calling into ffmeg doesn't then you get trouble

There is a GCC option called "-mstackrealign" which should help with that. At least, it will do "and esp, -16" (maybe a bit more extra stuff beyond just that) which should help you.

IIRC, DJGPP's linkable COFF .o format is a bit less flexible in alignment (always four bytes??) versus MS COFF or other formats. You may instead wish to manually align the stack only for certain functions via attribute force_align_arg_pointer.

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Complete thread:

SSE instructions in DOS programs? - Laaca, 02.01.2019, 00:07
- SSE instructions in DOS programs? - alexfru, 02.01.2019, 00:31
- SSE instructions in DOS programs? - Rugxulo, 02.01.2019, 10:08
- SSE instructions in DOS programs? - RayeR, 02.01.2019, 22:56
  - SSE instructions in DOS programs? - Laaca, 03.01.2019, 12:51
    - SSE instructions in DOS programs? - Laaca, 03.01.2019, 12:52
    - SSE instructions in DOS programs? - RayeR, 03.01.2019, 14:32
      - SSE instructions in DOS programs? - RayeR, 03.01.2019, 14:39
  - SSE instructions in DOS programs? - marcov, 04.01.2019, 23:37
    - SSE instructions in DOS programs? - Rugxulo, 12.01.2019, 23:54
      - SSE instructions in DOS programs? - RayeR, 13.01.2019, 16:44