assembly/dino.asm

SYS_EXIT equ 1
SYS_READ equ 3
SYS_WRITE equ 4
STDIN equ 0
STDOUT equ 1
SYS_IOCTL equ 54

section .bss
	sz RESB 4 ; 4 byte for window size
	num resb 4 ;4 byte for ascii numbers

section .data
	ha db  0 ;hundreds
	ta db 0 ;tens

section .text
	global _start

_start:
	; get windwo size	
	mov eax, SYS_IOCTL	; syscall ioctl
	mov ebx, STDOUT		; stdout for something?
	mov ecx, 0x5413		; get windowsize command TIOCGWINSZ
	mov edx, sz		; target struct
	int 0x80		; call kernel


	; print rows

	mov ecx, [sz+0]		;rows in ecx

hundreds:
	cmp ecx, 100		;check if above 100
	jge inchundred		;jump to increment hundreds if needed
	
	mov eax,[ha]		;hundred count to eax
	add eax, '0'		;convert to ascii
	mov [num+0], eax	;move to first byte of num string

tens:
	cmp ecx, 10		;check if above 10
	jge inctens		;jump to increment tens if needed
	
	mov eax,[ta]
	add eax, '0'
	mov [num+1], eax

	mov eax, ecx
	add eax, '0'
	mov [num+2], eax	
	mov [num+3], byte 0xa 	;linebreak

	mov eax, SYS_WRITE
	mov ebx, STDOUT
	mov ecx, num
	mov edx, 4
	int 0x80

	; print cols

	mov eax, SYS_WRITE
	mov ebx, STDOUT
	mov ecx, sz+2
	mov edx, 3
	int 0x80

exit:
	;exit
	mov eax, 1
	mov ebx, 0
	int 0x80

inchundred:
	inc byte [ha]		;increment hundreds
	sub ecx, 100
	jmp hundreds

inctens:
	inc byte [ta]		;increment tens
	sub ecx, 10
	jmp tens