; Recreation from disassembly, changing org 0x2000 to 0x3000 should produce
; a binary runnable on current (as of 2021-07-09) EttinOS
cpu 8086
org 0x2000

mov ah, 3
mov al, 255
mov di, buffer
int 0x21

mov bx, buffer

rotloop:
	cmp byte [bx], 0
	jz .end

	cmp byte [bx], 'A'
	jl .next
	cmp byte [bx], 'M'
	jle .inc
	cmp byte [bx], 'Z'
	jle .dec

	cmp byte [bx], 'a'
	jl .next
	cmp byte [bx], 'm'
	jle .inc
	cmp byte [bx], 'z'
	jle .dec

	.next:
		inc bx
		jmp short rotloop

	.inc:
		add byte [bx], 13
		jmp short .next
	.dec:
		sub byte [bx], 13
		jmp short .next
	.end:

mov ah, 2
mov si, buffer
int 0x21
int 0x20

buffer: