Re: announce: my very first disassembler now available (GPL)

"Willow" <wrschlanger@xxxxxxxxx> wrote in message
news:995fd23b-dc80-4760-b80a-fef07ac020d2@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
If you have time, can you repeat the experiment on the latest version
and let me know how it goes?
Thanks a bunch!!!


There are some trivial things I didn't list, e.g., "aad 0x0a" vs. "aad"...

First, there are some differences between 0.10 and 0.11 you should note:
--
0.10 has many more size keywords: "byte", "word", "dword"
0.10 doesn't have some "far" and "near" keywords on call, jmp, etc. and
other issues those instructions

0.11 has "<unsupported size>" on lgdt,lidt,sidt
0.11 has the string instructions correct

Second, differences between 0.10 and Ndisasm (2.03.01):
--
0.10 has similar problems as above versus ndisasm
0.10 has "xchg ax,ax" (actually correct...) for "nop"

Third, differences between 0.11 and Ndisasm (2.03.01):
--
0.11 has differences in size keywords, and "short" and "near"

0.11 has problem with size keyword for "bound":
bound ax,word:word [0xffff]
bound eax,dword:dword [0xffff]

0.11 has qword:
cmpxhg8b qword [0xffff]

0.11 has <unsupported size> on lgdt,lidt,sidt:
lgdt word:<unsupported size> [0xffff]
lidt word:<unsupported size> [0xffff]
lidt word:<unsupported size> [0xffff]

0.11 has "xchg ax,ax" (correct...) for "nop"

0.11 has sgdt as:
sgdt word:qword [0xffff]

Except for some of the size and "short"/"near" keywords differences versus
Ndisasm, I'd say looking pretty good for 16-bit! At this point, you can
throw some random binaries at Ndisasm 0.98.39 and 2.03.01 and your versions
of crudasm and look for differences or problems such as bad or invalid
decodes.


Rod Pemberton

.

Relevant Pages

  • Re: NASM 0.98.39 vs. NASM 2.03.01 disassembly
    ... demonstrate that LSL and LAR aren't to be encoded or decoded as 16-bit only, ... I also posted in the bug report where Intel ... The bug was found by comparing Ndisasm output ... Ndisasm disassemble the LAR and LSL instructions. ...
    (alt.lang.asm)
  • Re: NDISASM : Disassembly shows different instructions!!
    ... > here after using ndisasm, i can't see call instruction at all. ... Hi Anish, ... These instructions disassemble okay for me. ...
    (comp.lang.asm.x86)