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.
