DOS ain't dead

Question about some x86 opcodes (Developers)

posted by Japheth , Germany (South), 02.11.2008, 17:51

> Even if DOS world, many software writers do not care about anything below
> 386 nowadays. But I like to maintain compatibility whenever possible. And,
> last but not least, the ability to save one byte of code is sometimes
> critical
>
> Can anyone help?

There is an option in Masm:

OPTION NOSIGNEXTEND

and the documentation says:

NOSIGNEXTEND Overrides the default sign-extended opcodes for the AND, OR, and XOR instructions and generates the larger non-sign-extended forms of these instructions. Provided for compatibility with NEC V25 and NEC V35 controllers.

---
MS-DOS forever!

Complete thread:

• Question about some x86 opcodes - mht, 02.11.2008, 14:02 (Developers)
  • Question about some x86 opcodes - Japheth, 02.11.2008, 17:51
  • Question about some x86 opcodes - DOS386, 03.11.2008, 10:04
    • Question about some x86 opcodes - mht, 05.11.2008, 19:54
      • Question about some x86 opcodes - Rugxulo, 06.11.2008, 21:06
        • Question about some x86 opcodes - mht, 08.11.2008, 08:46
          • Question about some x86 opcodes - Rugxulo, 12.11.2008, 00:43
            • Question about some x86 opcodes - mht, 12.11.2008, 16:54
              • Question about some x86 opcodes - mht, 22.11.2008, 13:59