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Re: can i ignore safely address size prefix in real mode?
Posted: Tue Sep 10, 2013 3:36 pm
by newanabe
if it is matter of only using ESI instead SI for address calculation, when using address size prefix, it would be simple to code that, but for certain combinations, NASM just goes crazy, I cant code that crazy >15 bytes opcodes!!!
Re: can i ignore safely address size prefix in real mode?
Posted: Wed Sep 11, 2013 3:56 am
by newanabe
after two days of coding, here is the output for the "1000 00xxh xx11 1xxxb" opcode. I will have to revise the code today and hopefully it will be easy to reuse big part of it for many of the other opcodes, so I can speed up the coding process. Lock and address size prefixes are just ignored and logged at this point. This is the first time I create a log file and for now it results interesting for me.
It would be great to add some extra logging for the values of the registers at the time instructions are executed, like:
cmp [DS:SI], 1234h ;compare 8543h at [00007345h] with 1234h
It suppose an extra work but it feels good to have a precise log and know better what is happening.
(The nasm output is a bit different where the address size prefix was used)