global _putint
global putcharhex
global _putcharhex
global putstr
global _putstr
_putint:
push bp
mov bp, sp
mov ax, word [bp+4] ; ax=argument
sub sp, 8 ; 5 bytes - printing buffer
pusha
mov di, -1 ; dest index
mov si, 10 ; divisor, ax=dividend
putint_divloop:
mov dx, 0 ; clear upper bits
div si
add dx, '0'
mov byte [bp+di], dl
dec di
cmp ax, 0
ja putint_divloop
mov ah, 0x0e
mov bx, 0x0007
putint_print:
inc di
mov al, byte [bp+di]
int 0x10
cmp di, -1
jl putint_print
popa
mov sp, bp
pop bp
ret
_putcharhex:
push bp
mov bp, sp
mov cl, byte [bp+4]
call putcharhex
mov sp, bp
pop bp
ret
putcharhex: ; cl=argument
mov dx, bx ; preserve bx
mov ah, 0x0e
mov bx, 0x0007
mov al, cl
and al, 0xf0
shr al, 4
call fourbit2hex
int 0x10
mov al, cl
and al, 0x0f
call fourbit2hex
int 0x10
mov bx, dx ; restore bx
ret
fourbit2hex: ; al=argument=result
cmp al, 10
jae fourbit2hex_alpha
add al, '0'
ret
fourbit2hex_alpha:
add al, 'A' - 10
ret
_putstr:
push bp
mov bp, sp
mov dx, word [bp+4]
call putstr
mov sp, bp
pop bp
ret
putstr: ; dx=argument
mov cx, bx ; we must preserve bx
putstr_start:
mov bx, dx ; [dx] is not a effective address
mov al, byte [bx]
test al, al
jz putstr_end
mov ah, 0x0e
mov bx, 0x0007
int 0x10
inc dx
jmp putstr_start
putstr_end:
mov bx, cx
ret
