DOS ain't dead - NASM 2.10 uses "-Ox" by default

NASM 2.10 uses "-Ox" by default (Announce)

posted by Rugxulo , Usono, 03.05.2012, 08:18

> I think that -Ox requires more passes than, say, -O0 - so
> historically, the build process took less time. This is less
> relevant today, so the trade-off between optimising the build
> process and the actual run time performance has here been
> changed to prioritise the latter.

Yeah, NASM -O0 was faster, more noticeable to me on my old P166 than newer stuff. However, I think YASM by default was always faster than NASM, and of course FASM blew them both out of the water.

> No, "strict" is for specific instructions only.

I don't know the details, just know that the very few who needed such things often seemed happy to use "strict".

> If, however, you want to have the not-optimising behaviour everywhere, you
> only have to select -O1 or -O0 (the last one again being digit zero).

Not as painful as it sounds (though it is a change from years past), esp. if you use Makefiles or set the NASMENV (or whatever) environment variable.

> That should in general be limited to special usages though (like Rayer testing
> whether the output is byte-compatible here).

Any kind of assembly code depending on specific opcodes or sizes is likely to bite you later and should (probably?) be avoided (or else hardcoded in "db 0x9, 0x10" directly). IMHO, YMMV. ;-)

> Do FASM and YASM have equivalents to -O0 and strict?

I'm fairly certain you can override sizes in the source, yes, but no, I don't think you can disable size optimizations at runtime at all (though perhaps limiting FASM passes would somewhat work). No reason to do so, honestly, though I may be short-sighted in believing that. (I hate such generalizations when people say, "Nobody needs xyz.")

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Complete thread:

NASM 2.10 - Rugxulo, 27.03.2012, 00:39 (Announce)
- NASM 2.10 - Rugxulo, 27.03.2012, 00:42
  - NASM 2.10 - marcov, 27.03.2012, 13:07
  - NASM 2.10 - revised preprocessor - ecm, 20.04.2012, 04:26
    - NASM 2.10 - revised preprocessor - RayeR, 02.05.2012, 22:06
      - NASM 2.10 - revised preprocessor - ecm, 02.05.2012, 22:16
        NASM 2.10 - revised preprocessor - RayeR, 02.05.2012, 22:43
        NASM 2.10 - revised preprocessor - ecm, 02.05.2012, 22:48
        NASM 2.10 - revised preprocessor - RayeR, 03.05.2012, 00:04
        NASM 2.10 uses "- Ox" by default - Rugxulo, 03.05.2012, 02:25
        NASM 2.10 uses "-Ox" by default - ecm, 03.05.2012, 02:37
        NASM 2.10 uses "-Ox" by default - Rugxulo, 03.05.2012, 08:18
        NASM 2.10 uses "-Ox" by default - ecm, 03.05.2012, 23:00
        NASM 2.10.01 - Rugxulo, 16.06.2012, 00:24
        NASM 2.10 - revised preprocessor - ecm, 03.05.2012, 02:26