Thread: Ambermoon
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Old 14 July 2009, 14:32   #216
Bad Taste Development
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Join Date: Jul 2008
Location: Bonn / Germany
Age: 46
Posts: 48
Originally Posted by StingRay View Post
Which assembler are you using that allows instructions like that?
Quite a few actually accept that illegal form, perhaps due to the way they parse instructions. PhxAss and SAS/C's asm (which I both use myself) do, for example.

Many disassemblers only look at bit patterns when trying to decode something. SAS/C's OMD and CPR produce the illegal instructions maynef posted, as well. Resource recognizes them as illegal as does the old "dis" I still use.

Originally Posted by StingRay View Post
Edit2: Checked with different ASM1 version which indeed assembles it. The instruction still doesn't make any sense to me.
It's illegal, plain and simple. Even if an assembler accepts it and the disassembler you use gives you the same instruction as output doesn't mean the CPU will do what you think the instruction does. Might work on one model, fail on the other. Might work on one chip revision, fail on the other.
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