HC11 disassembler wanted

[T Hergen]

I think Ludis is correct.  Not even Motorola claims the 68hc11 is a
superset of the 6809 (in the Motorola data books I have).  Motorola claims
"Source Code Compatible..." for the 6809 compared to the 6800, but this
does not mean all the ones and zeros are the same (as alluded to in a
previous post).   

As an example of a 6809 opcode that does something different on a 68hc11,
check 0x1C (in various programming languages, hex number are often
preceeded by a "0x" to differentiate them from decimal numbers). It's BSET
on the hc11 and ANDCC on the 6809.  I think they even have a different
number of operands which means the next instruction starts at a different
point in the two processors (may mess up disassembly of next instruction).

Both the 68hc11 and 6809 have 6800 heritage, so there are numerous
similiarities.

What this means is that a 6809 disassembler will give incorrect results
for some opcodes (and the following opcodes in some cases) when used to
process 68hc11 code.  Alot of the results may still be useful, just watch
out for the limitations. 

Tom


On Fri, 25 Sep 1998, Roger Heflin wrote:

> 
> 
> On Fri, 25 Sep 1998, Ludis Langens wrote:
> 
> > Joe Boucher <BoucherJC at lmtas.lmco.com> wrote:
> > > I am definitely not an expert in this area.  I'm just parroting something I read.  You
> > > might try using a 6809 disassembler on the code.  My understanding is the 68HC11 is
> > > based on the 6809 and the 6809 instructions are a subset of the 68hc11 instructions and
> > > you might have better success than you might think.  There are 6809 disassemblers
> > > available for free.
> > 
> > HALT!  Go directly to Radio Shack.  Do not pass IRQ.  Do not collect
> > $200 of 6809 tools.
> > 
> > The 6809 is different from the 6800/6801/68HC11.  It was (one of)
> > Motorola's upgrade path(s) from the 6800 - in the same way that Intel
> > went from the 8080 to the 8086/8088.  In both cases, old assembly source
> > code could be mechanically translated to the new design.  But neither
> > one was object code compatible.
> > 
> > The most famous use of the 6809 is the Radio Shack Color Computer
> > (CoCo).  The most famous 6809 operating system is OS-9.
> 
> 
> Incorrect.  The every 6809 instruction is in the 68HC11, with the same binary
> opcode.  The 68HC11 has extra I/O ports and some extra commands not found
> in a 6809, but any 6809 code should work on a 68HC11 chip.  The 68HC11 is
> an upgraded improved 6809, the 6809 is an upgrade from the 6800 and the
> 68HC11 is an upgrade from the 6809.    The 6800 and the 6809 were used in
> alot of embedded designs, and the 68HC11 added more features and more of
> the neccessary instructions and features for Motorola to keep this market.
> The primary difference between a 6809 and the HC11 is the HC11 has several
> extra instrutions and alot of mask options for A/D D/A, I/O, and other useful
> stuff for the embedded market.   
> 
> 
> Another comment: to the person that could only find a simulator for the
> 68HC11, the simulator has a disassembler in it and will work just find to
> disassemble to code, it just takes a few (10-20) more keystrokes to get
> the job done, but it works quite well.
> 
> 				Roger
>