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Sarverott/asm-worm.a80.asm

Last active March 16, 2023 19:53
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code in assembler for Intel 8080, that is self-replicatory virus example. Written for fun for 80's old school microprocessor unit. Tested on http://asm80.com/ and https://github.com/eliben/js-8080-sim emulators
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asm-worm.a80.asm
;asmWorm - self-replication code in assembler for Intel 8080
;Sett Sarverott @ 2022
lxi h, 0000h ;start read
lxi d, 002fh ;stop read/start write
mvi c, 2fh ;length
mvi a, 00h ;index
replicator:
;copy this code to space after this code
mov b, m ;b=*read_pointer
xchg
mov m, b ;*write_pointer=b
xchg
inx h ;read_pointer++
inx d ;write_pointer++
inr a ;index++
cmp c ;flags=index-length
jnz replicator ;if(flags!=0) goto replicator label
;constants update
mov b, h
mov c, l
inx h
mov m, c
inx h
mov m, b
;lxi h in line 3 - read start
inx h
inx h
mov m, e
inx h
mov m, d
;lxi h in line 4 - write start
lxi d, 000eh
dad d
;get line 19 in compiled ram - jnz replicator (label in complied code is constant memory addres)
mov d, b
mov e, c
lxi d, 000ah
xchg
dad b
;get line 7 label address
xchg
mov m, e
inx h
mov m, d
;jnz in line 19 updated with new address of label in line 5 for copy
;after that execute new code written after last command of current code
;effect - after execution of code independent and fully operational copy starts on end of current code
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