cpu 8086
	org 256
start:
	xor di, di
	xor ax, ax
	xchg ax, [di + 2Ch]
	mov es, ax
	mov ah, 49h
	int 21h

	mov ah, 52h
	int 21h
	mov ax, [es:bx - 2]
	mov es, ax
	cmp word [es:di + 1], 0
	jne error

	mov ax, 1261h
	stc
	int 2Fh
	jc error
	xor bx, bx
.loop:
	mov ds, ax
	cmp byte [di], 'Z'
	je .last
	cmp byte [di], 'M'
	jne error
	mov bx, ax
	add ax, word [di + 3]
	inc ax
	jmp .loop

.last:
	test bx, bx
	jz error
	cmp word [di + 1], 8
	jne error
	cmp word [di + 3], 0
	jne error
	cmp word [di + 8], "S"
	jne error
	cmp byte [di + 10], 30h
	jne error

	mov ds, bx
	cmp word [di + 1], 0
	jne error

	mov ax, 5801h
	mov bx, 382h
	stc
	int 21h
	jc error

	int3
	mov byte [di], 'Z'

	mov ah, 48h
	mov bx, -1
	int 21h

	mov ax, 4C00h
	int 21h

error:
	int3
	mov ax, 4CFFh
	int 21h