Unknown 8085 opcodes

Fred Cisin cisin at xenosoft.com
Wed Jan 11 11:49:24 CST 2017


On Wed, 11 Jan 2017, Adrian Graham wrote:
> Well, this is ROM dumps of a telephone system so that would make sense for
> some of it, but surely a disassembler should also recognise that it's ASCII
> string data and treat it accordingly? I can imagine a freeware disassembler
> maybe making that mistake but the second one is commercial.

"mistake"?
Maybe give you an out-of-channel text message?, but it did what you asked 
for, which was to interpret that section as CODE.

Sometime, try creating a .COM file in MS-DOS that starts with
DEC BP
POP DX
The loader in MS-DOS recognizes that as Mark Zbikowski's initials, and 
will process the file as an .EXE, instead of .COM (disunirregardless of 
.COM V .EXE file extension)

> I'll have a closer look at DASMx's parameters when I get home, that's the
> freeware one but it seems to make a better job of it than the commercial
> version, though both the D8741A and ROM dumps produce the same unknown
> opcodes.
> If anyone knows of others please shout up.

Yes, wouldn't it be nice if a disassembler would have the smarts to 
recognize that certain bites are text, to decipher 32 bit floating point 
numbers, parse and display AES DIRectory entries, notice and invert 
BIG-endian V little-endian numbers, look up what any INT call is heading 
for, recognize string terminator characters, and spell check any text that 
it finds, . . .


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