global to_int

section .text

;
; angle translation from string to integer
; [ebp+8] is pointer to string
; eax=-1 if digit is not 0-9
; else eax=number
;
to_int:		push ebp
		mov ebp, esp
		sub esp, 8		; local variables
		push esi		; save esi
		mov dword [ebp-4], 0	; init number
		mov dword [ebp-8], 10	; init const
		mov esi, [ebp+8]	; buffer
		cld
.lp:		lodsb
		cmp al, 0
		je .store
		cmp al, '0'
		jl .error
		cmp al, '9'
		jg .error
		sub al, '0'
		xor ecx, ecx
		xchg al, cl
		mov eax, [ebp-4]
		mul dword [ebp-8]
		add eax, ecx
		mov [ebp-4], eax
		jmp .lp
.error:		mov eax, -1
		jmp .quit
.store:		mov eax, [ebp-4]
.quit:		pop esi
		mov esp, ebp
		pop ebp
		ret