259 lines
3.7 KiB
ArmAsm
259 lines
3.7 KiB
ArmAsm
; call # val val2
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; int $0x80 eax eax edx -
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;
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; arg1 arg2 arg3 arg4 arg5 arg6 arg7
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; ebx ecx edx esi edi ebp -
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exit:
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mov eax, 1 ; exit
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int 0x80
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; filename in EBX
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; return handle in EBX
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; read only
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open_file:
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push eax
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push ecx
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mov eax, 5 ; open
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xor ecx, ecx ; read only
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int 0x80
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mov ebx, eax
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pop ecx
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pop eax
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ret
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; file handle in EBX
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; buffer in ECX
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; count of bytes to read in EDX
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; return bytes actually read in EAX
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; exits on error
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read_file:
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mov eax, 3 ; read
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int 0x80
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test eax, eax
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js .err
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ret
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.err:
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mov eax, 4 ; write
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mov ebx, 1 ; stdout
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mov ecx, .err_str
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mov edx, 21
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int 0x80
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jmp exit
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.err_str: db `Could not read file.\n`
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; string input in ESI
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; value in EAX
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; CF set if none, clear if some
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; ESI set past checked area
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dec_parse:
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push ebx
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push edx
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push edi
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xor eax, eax
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xor edi, edi
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mov ebx, 10 ; base
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lodsb
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sub al, '0'
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js .no_input
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cmp al, 9
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jle .got_char
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.no_input:
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stc ; set CF
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jmp .done
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.loop:
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xor eax,eax
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lodsb
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sub al, '0'
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js .dec_done
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cmp al, 9
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jg .dec_done
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.got_char:
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xchg edi,eax
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mul ebx
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add edi,eax
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jmp .loop
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.dec_done:
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clc ; clear CF
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.done:
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mov eax,edi
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pop edi
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pop edx
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pop ebx
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ret
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; string input in ESI
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; value in EAX
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; CF set if none, clear if some
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; ESI set past checked area
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sign_dec_parse:
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push ebx
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push ecx
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push edx
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push edi
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xor eax, eax
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xor edi, edi
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xor ecx, ecx ; neg flag
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mov ebx, 10 ; base
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cmp byte [esi], '-'
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jne .no_minus
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inc esi
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mov cl, 1
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.no_minus:
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lodsb
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sub al, '0'
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js .no_input
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cmp al, 9
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jle .got_char
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.no_input:
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stc ; set CF
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jmp .done
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.loop:
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xor eax,eax
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lodsb
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sub al, '0'
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js .dec_done
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cmp al, 9
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jg .dec_done
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.got_char:
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xchg edi,eax
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mul ebx
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add edi,eax
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jmp .loop
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.dec_done:
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test ecx, ecx
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jz .not_neg
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neg edi
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.not_neg:
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clc ; clear CF
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.done:
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mov eax,edi
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pop edi
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pop edx
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pop ecx
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pop ebx
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ret
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; modifies no regs
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newline:
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pushad
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push 10
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mov eax, 4 ; write
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mov ebx, 1 ; stdout
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mov ecx, esp ; string
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mov edx, 1 ; length
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int 0x80
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add esp, 4
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popad
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ret
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; modifies no regs
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space:
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pushad
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push 9
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mov eax, 4 ; write
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mov ebx, 1 ; stdout
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mov ecx, esp ; string
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mov edx, 1 ; length
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int 0x80
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add esp, 4
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popad
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ret
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; input in EAX, all regs unmodified
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print_dec:
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pushad ; save regs
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; max 4294967296 is 10 chars
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; round to nearest 32-bit boundary
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sub esp, 12
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; string in ECX, length in EDX
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lea ecx, [esp+11] ; last possible byte
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; check for 0
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test eax, eax
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jz .zero
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mov ebx, 10 ; base 10
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xor esi, esi ; counter
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.div_shit:
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xor edx, edx
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; divide
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div ebx
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dec ecx ; next char
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inc esi
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; store
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add dl, '0'
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mov byte [ecx], dl
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; check if done
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test eax, eax
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jnz .div_shit ; continue
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mov edx, esi ; counter in edx
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jmp .write
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.zero:
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mov byte [ecx], '0'
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mov edx, 1 ; length
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.write:
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mov eax, 4 ; write
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mov ebx, 1 ; stdout
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int 0x80
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add esp, 12 ; restore stack
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popad ; restore regs
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ret
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; input in EAX, all regs unmodified
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print_sign_dec:
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pushad ; save regs
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; range -2147483648 to 2147483647 is 11 chars
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; round to nearest 32-bit boundary
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sub esp, 12
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; string in ECX, length in EDX
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lea ecx, [esp+11] ; last possible byte
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; check for 0, negative
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xor ebp, ebp
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test eax, eax
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jz .zero
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jns .positive
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neg eax
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mov ebp, 1
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.positive:
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mov ebx, 10 ; base 10
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xor esi, esi ; counter
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.div_shit:
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xor edx, edx
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; divide
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div ebx
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dec ecx ; next char
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inc esi
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; store
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add dl, '0'
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mov byte [ecx], dl
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; check if done
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test eax, eax
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jnz .div_shit ; continue
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mov edx, esi ; counter in edx
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jmp .write
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.zero:
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mov byte [ecx], '0'
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mov edx, 1 ; length
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.write:
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test ebp, ebp
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jz .no_minus
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dec ecx
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inc edx
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mov byte [ecx], '-'
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.no_minus:
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mov eax, 4 ; write
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mov ebx, 1 ; stdout
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int 0x80
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add esp, 12 ; restore stack
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popad ; restore regs
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ret
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; input in ESI, len in ECX, all regs unmodified
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print_string:
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pushad ; save regs
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mov eax, 4 ; write
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mov ebx, 1 ; stdout
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mov edx, ecx ; length
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mov ecx, esi ; string
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int 0x80
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popad ; restore regs
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ret
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