66 lines
835 B
NASM
66 lines
835 B
NASM
SECTION .text
|
|
USE16
|
|
; provide function for printing in x86 real mode
|
|
|
|
; print a string and a newline
|
|
; IN
|
|
; si: points at zero-terminated String
|
|
; CLOBBER
|
|
; ax
|
|
print_line:
|
|
mov al, 13
|
|
call print_char
|
|
mov al, 10
|
|
jmp print_char
|
|
|
|
; print a string
|
|
; IN
|
|
; si: points at zero-terminated String
|
|
; CLOBBER
|
|
; ax
|
|
print:
|
|
cld
|
|
.loop:
|
|
lodsb
|
|
test al, al
|
|
jz .done
|
|
call print_char
|
|
jmp .loop
|
|
.done:
|
|
ret
|
|
|
|
; print a character
|
|
; IN
|
|
; al: character to print
|
|
; CLOBBER
|
|
; ah
|
|
print_char:
|
|
mov ah, 0x0e
|
|
int 0x10
|
|
ret
|
|
|
|
; print a number in hex
|
|
; IN
|
|
; bx: the number
|
|
; CLOBBER
|
|
; cx, ax
|
|
print_num:
|
|
mov cx, 4
|
|
.lp:
|
|
mov al, bh
|
|
shr al, 4
|
|
|
|
cmp al, 0xA
|
|
jb .below_0xA
|
|
|
|
add al, 'A' - 0xA - '0'
|
|
.below_0xA:
|
|
add al, '0'
|
|
|
|
call print_char
|
|
|
|
shl bx, 4
|
|
loop .lp
|
|
|
|
ret
|