Disassembling and Assembling 8048 Binaries
In this article, I showed how to compile D52. In this article, I showed how to disassemble and assemble 8048 code. Well, it turns out that if you try and do this same technique with Odyssey 2 binaries, you run into problems. After struggling, I found a disassembler/assembler here that works well for this. I also put a copy of the source up here. Let's compile:
usr-1@wrk-1 usr-1 $ ls asm*
asm48-0.0-src.tar.gz
usr-1@wrk-1 usr-1 $ tar -xzf asm*.gz
usr-1@wrk-1 usr-1 $ cd asm*
usr-1@wrk-1 asm48-0.0 $ ls
8039dasm.c asm48.c err.c ihex.c parse.y symtab.
Makefile asm48.h expr.c instruction.c pool.c test.as
README asmdasm getopt.c lex.l runtest test2.a
usr-1@wrk-1 asm48-0.0 $
ne@wrk-1 asm48-0.0 $ make
bison -d parse.y
gcc -O -Wall -DHAVE_GETOPT -c parse.tab.c -o parse.o
flex lex.l
gcc -O -Wall -DHAVE_GETOPT -c lex.yy.c -o lex.o
lex.yy.c:1658: warning: `yyunput' defined but not used
gcc -O -Wall -DHAVE_GETOPT -c asm48.c
gcc -O -Wall -DHAVE_GETOPT -c instruction.c
gcc -O -Wall -DHAVE_GETOPT -c expr.c
gcc -O -Wall -DHAVE_GETOPT -c symtab.c
gcc -O -Wall -DHAVE_GETOPT -c pool.c
gcc -O -Wall -DHAVE_GETOPT -c err.c
gcc -O -Wall -DHAVE_GETOPT -c ihex.c
gcc -o asm48 parse.o lex.o asm48.o instruction.o expr.o symtab.o pool.o err.o ihex.o -lfl
gcc -O -Wall -DHAVE_GETOPT -c 8039dasm.c
gcc -o 8039dasm 8039dasm.o
usr-1@wrk-1 asm48-0.0 $
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Let's grab an Odyssey 2 ROM image from here, and disassemble and assemble it:
usr-1@wrk-1 asm48-0.0 $ ./8039dasm AMOKPD.BIN 0 4096 > amok.asm
usr-1@wrk-1 asm48-0.0 $ head amok.asm
jmp $02C3
jmp $0009
call $040C
jmp $001A
jmp $040D
jmp $0044
retr
call $0176
call $00EC
call $00E7
usr-1@wrk-1 asm48-0.0 $ tail amok.asm
dis tcnti
movd a,p4
movd a,p4
movd a,p4
movd a,p4
movd a,p4
movd a,p4
movd a,p4
movd a,p4
movd a,p4
usr-1@wrk-1 asm48-0.0 $ ./asm48 amok.asm
Memory 0000 to 0FFF written to 'amok.hex'
usr-1@wrk-1 asm48-0.0 $
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OK. Now we have amok.hex. This is not the format of the original binary, it needs to be converted to a bin format. A good program to do this is here. We put a copy of the source up here. To convert:
usr-1@wrk-1 asm48-0.0 $ hex2bin amok.hex
hex2bin v1.0.1, Copyright (C) 1999 Jacques Pelletier
Lowest address = 00000000
Highest address = 00000FFF
usr-1@wrk-1 asm48-0.0 $
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Let's see if we match:
usr-1@wrk-1 asm48-0.0 $ diff amok.bin AMOKPD.BIN
usr-1@wrk-1 asm48-0.0 $
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No difference. All is good.
D52 gives a prettier, and more readable listing, so it may be helpful to understand your disassembly. For instance, if you use the -d option, you will get this:
usr-1@wrk-1 d52v33beta $ ./d48 -d amokpd
D48 8048/8041 Disassembler V 3.3
Copyright (C) 1996-2004 by J. L. Post
Released under the GNU General Public License
Initializing program spaces...
reading amokpd.bin
Highest location = 0fff
;
; 8048 Disassembly of amokpd.bin
; 04/11/04 5:56
;
org 0
;
X0000: jmp X02c3 ; 0000 - 44 c3 DC
;
jmp X0009 ; 0002 - 04 09 ..
;
call X040c ; 0004 - 94 0c ..
jmp X001a ; 0006 - 04 1a ..
;
jmp X040d ; 0008 - 84 0d ..
.
.
.
X09c3 equ 9c3h
X0a0d equ 0a0dh
X0b30 equ 0b30h
X0b3f equ 0b3fh
X0b70 equ 0b70h
X0b87 equ 0b87h
X0bb9 equ 0bb9h
X0bea equ 0beah
X0c0d equ 0c0dh
X0dc5 equ 0dc5h
X0dea equ 0deah
X0e70 equ 0e70h
X0e72 equ 0e72h
X0f0e equ 0f0eh
X0f14 equ 0f14h
X0f19 equ 0f19h
X0f1e equ 0f1eh
X0f20 equ 0f20h
X0f24 equ 0f24h
;
end
;
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