; Public Domain

	cpu 8086

	section CODE
..start:
	mov ax, FIRST
	mov es, ax
	mov dx, REPEAT
loop:
	mov ax, 2626h
	mov cx, BLOCKSIZE / 2
	xor di, di
	repe scasw
	jne bad
	dec dx
	jz good
	mov ax, es
	add ax, BLOCKSIZE / 16
	mov es, ax
	jmp loop

bad:
	int3
	mov ax, es
	mov bx, cs
	sub ax, bx
	call disp_ax_hex
	mov dl, ':'
	mov ah, 02h
	int 21h
	mov ax, di
	call disp_ax_hex
	mov dl, 13
	mov ah, 02h
	int 21h
	mov dl, 10
	mov ah, 02h
	int 21h
	mov ax, 4CFFh
	int 21h

good:
	mov ax, 4C00h
	int 21h

disp_ax_hex:
	xchg al, ah
	call .al
	xchg al, ah
.al:
	push cx
	mov cl, 4
	rol al, cl
	call .nybble
	rol al, cl
	pop cx
.nybble:
	push ax
	push dx
	and al, 15
	add al, '0'
	cmp al, '9'
	jbe .got
	add al, 7
.got:
	xchg dx, ax
	mov ah, 02h
	int 21h
	pop dx
	pop ax
	retn

REPEAT equ 64
BLOCKSIZE equ 1024

	section FIRST align=16
%assign id 0
%rep REPEAT
	section SECTION%+id align=16
	times BLOCKSIZE db 26h

%assign id id+1
%endrep

	section STACK stack
	resb 512