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> > From: email@example.com (H.J. Lu) > Date: Tue, 21 Apr 1998 12:34:46 -0700 (PDT) > > > Why not encourage people to write the prefix on a separate line, which > > works for both a.out and ELF? > > > > That is a separate issue. Since PREFIX_SEPARATOR is wrong on ELF, we > should fix it. I think we can change it > > #define PREFIX_SEPARATOR '\\' > > so that everyone will be happy. > > I am questioning the need for PREFIX_SEPERATOR at all. I don't see > any particular reason to use it on ELF if it is not required and if no > other ELF assembler supports it. The only reason I can think of is that we may want to treat prefixes on a separate line differently to prefixes specified "with the instruction" eg. We might find it desirable for ds lgdt 0 to emit the ds prefix while ds/ldgt 0 (or whatever the syntax is) or lgdt %ds:0 shouldn't. ie. gas realises that ds is the default segment. Martynas (firstname.lastname@example.org) has been working on a 16 bit capable gas, and he's keeping track of address size prefixes as a means to tell the assembler that the next instruction is a 16 bit one. For instance `addr16; mov 0,%ebx' generates 67 8b 1e 00 00 while `mov 0,%ebx' generates 8b 1d 00 00 00 00 So the `addr16' can't just be emitted; It considerably effects following code, and not just offset sizes, but modrm bytes too. I'm wondering if this is really a good idea. Maybe it would be better if addr16 didn't effect the code generated, and instead we require a `.code16' directive. How do other unix assemblers handle 16 bit code? Or don't they? Can someone with access to Unixware, SCO, etc. assemblers do some experimentation please?