| Readme: | Short: Disassembler for Intel 8080 processor
Author: martin@fripost.org (Martin �berg)
Uploader: polluks+aminet sdf lonestar org (Stefan Haubenthal)
Type: dev/cross
Architecture: m68k-amigaos; ppc-morphos
About
=====
dis8080 is an Intel 8080 instruction disassembler. It reads machine
code from standard input and writes the disassembly to standard
output.
Usage
=====
dis8080 [-d ADDR COUNT]
The option -d ADDR COUNT tells the disassembler to emit data
definitions instead of instructions for COUNT bytes, starting at
input offset ADDR. This option can be used multiple times.
Output from dis8080 can be assembled with an assembler such as vasm
or asmx.
Build
=====
Compile dis8080 with an ANSI C compiler:
cc dis8080.c -o dis8080
Examples
========
To disassemble the file example/add.bin, issue:
./dis8080 < example/add.bin
It generates the following output.
-----------------------------------------------------
lxi b,L0009
lxi h,L000A
jmp L000B
L0009:
mov d,d
L000A:
call L860A
ret
L000B = $000B
L860A = $860A
end
-----------------------------------------------------
This does not look quite right, because:
* The two "lxi" instructions hint that the values at label L0009
and L000A should be interpreted as data rather than instructions.
* "jmp" is unconditional so the "mov" will not be executed.
* The "jmp" target is inside the "call" instruction.
* "mov d,d" is not a commonly used instruction.
What is happening here is that the disassembler does not know that
following the "jmp" are two bytes of data, after which the program
instruction stream continues at address $000B. In other words, the
disassembler has become "out of phase". It is common to encounter
cases like this in production code.
To get a more realistic disassembly, mark the addresses $0009 and
$000A as data with the -d option:
./dis8080 < example/add.bin -d 0x0009 2
-----------------------------------------------------
lxi b,L0009
lxi h,L000A
jmp L000B
L0009:
db $52 ; 'R'
L000A:
db $cd
L000B:
ldax b
add m
ret
end
-----------------------------------------------------
Now this looks better as locations $0009 and $000A are interpreted
as data rather than instructions. At label L000B the two data bytes
in memory are added together.
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Ambient (143)
dis8080.lha