ZOMA Decompiled

%define MAGIC_LOC 0x1585
%define MAGIC_NUMBER 0x1567

00000000  83C05C            add ax,byte +0x5c ; ax = location + 0x5c
00000003  EB57              jmp short 0x5c ; jump to actual code



; step 1
; move es to arena
0000005C  1E                push ds
0000005D  07                pop es ; es -> arena


; step 2
; waste int 0x87
; search ax:dx
; replace with bx:cx
0000005E  CD87              int 0x87


; step 3
; get input from user
00000060  8B0E8515          get_input: mov cx,[MAGIC_LOC] ; get input from survivor
00000064  80F900            cmp cl,0x0
00000067  75F7              jnz get_input


; step 4
; initialize di
00000069  BF6715            mov di, MAGIC_NUMBER ; magic number

; remember:
;; ax -> our location + 0x5c
;; es -> arena
;; di -> some magic number
;; cx -> user input (ends with 0x00)









; step 5
0000006C  91                xchg ax,cx
; move user input to ax
; move our main code location to cx
0000006D  BB2100            mov bx,0x21
00000070  F7F3              div bx
;; div bx:
;; dx = ax % bx
;; ax = ax / bx

;; ax -> user input / 0x21
;; dx -> user input % 0x21


; step 6
; jump according to user params
00000072  01CA              add dx,cx ; dx -> our location + (user input % 0x21)
00000074  91                xchg ax,cx ; ax -> our location, cx -> user input / 0x21
00000075  FFE2              jmp dx
; jump to location stored in dx


; es -> arena
; di -> some magic number
00000077  B866AB            mov ax,0xab66
; stosw:
; mov [es:di], ax
; add di, 2







0000007A  BB9090            mov bx,0x9090
0000007D  F7F3              div bx
0000007F  89D1              mov cx,dx
00000081  EBFE              jmp short 0x81