Related to ASM

[Teller.John at orbital.com]

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 Subject: Related to ASM                                      
                                                              




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

Not really.  The 8086 (and especially 386, 486 and up) are very different
animals than the 68HC11.  The 68HC11 is a little 8-bit microcontroller,
while the 8086 and its bigger brothers are 16 bit (8086) and 32 bit (386+)
microprocessors.  What is the difference?  The 6811 has a bunch of on-board
peripherals that the microprocessors don't have, and the x86
microprocessors are much more complicated to program (different instruction
set, segmented memory access (8086), multiple modes the CPU can be in,
etc...).

Also the programming models used by Intel and Motorola are so different,
that many programmers will not cross the line to the other architecture
once they have worked in one camp or the other (I have to work with both
architectures every week).

>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?

Yes.  Compilers translate a (hopefully) processor-independent language to
object code that can be used by the processor it was written for.

>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.

Sometimes.  Disassemblers are relatively easy to write.  Decompilers are
incredibly difficult, especially when trying to decompile code that has
been produced by a highly optimized compiler!

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