Related to ASM

[Roger Heflin]

On Fri, 12 Feb 1999, Shannen Durphey wrote:

> Would learning assembly from a book for the x86 processors provide
> good base for disassembly work that will be done here, especially the
> 68HC11?
>

The instructions are different, but more likely than not everything is
very similar.  So someone that knew one assembly would be able to
easily understand another (if the have the sheets that explain how
the instructions work).
 
> Am I correct in thinking that a high level language provides a way to
> make a program, but is worthless without a compiler, and that
> compilers are processor specific?
> 

Compilers are processor specific, that is the part of the compiler
that generates the actual assembly code is processor specific, in the
case of the GCC compiler almost everything else is the same.

> And one more question.  Can a machine language program be disassembled
> into more than one high level language?  Hope I'm getting the jargon
> right.

Only if the compiler is straightforward.  Compilers often do rather
weird stuff, and often rearrange instructions.  If you knew
exactly what the compiler generated for a given input you may be able
to get pretty close, so long as it is not a serious optimizing
compiler.  You can probably get ASM code fairly readable once you
start to realize the sort of tricks that are done.

> 
> Remember, it's still cold out and the grasshopper may not be very
> quick yet.
> Shannen
> 
>