Eric Seppanen <[EMAIL PROTECTED]> writes: > On Wed, Feb 06, 2002 at 06:58:47PM +0200, Stefanos Papanicolopulos wrote: > > Collins Chen wrote: > > > I encounter a problem about instruction > > > "jmp" and "call". I expect the "jmp" and > > > "call" with a 16-bit offset, but every > > > time the GCC compile them with 32-bit offset. > > > This cause the vga bios can't run. I don't > > > know how to fix it, can you help me? Thanks! > > > > It seems your disassembler thinks the code runs > > in 32bit mode. Don't worry. As you see, GCC get's > > it right: the bytes are the same! The point is > > that E8 (call) has a 'word' as an argument. Now, > > in 16-bit mode, a word is 16bits. In 32-bit a > > 'word' is 32bits. So in 16bit mode E8 is followed > > by 2 bytes, in 32bit it is followed by 4. > > I can confirm that objdump does not seem to be able to disassemble > 16-bit assembly. > > I have also had problems with gcc not correctly generating 16-bit code > is some cases (in mixed 16/32bit code where symbols need to be resolved > later by the linker). I was not able to find a solution; maybe another > assembler would work better.
Hmm. In the rare cases with symbol relocation being an issue, I have been able to do the symbol computation in the linker script, though that may not be necissary. Eric
