.include "m8def.inc"

.cseg
.org 0
	rjmp	reset

// mirror bits in r16
// return value in r17
mirror8:
	lsl		r16
	ror		r17
	lsl		r16
	ror		r17
	lsl		r16
	ror		r17
	lsl		r16
	ror		r17
	lsl		r16
	ror		r17
	lsl		r16
	ror		r17
	lsl		r16
	ror		r17
	lsl		r16
	ror		r17
	ret

// mirror 32 bit, pointer to data in Z
mirror32:
	ld		r16, z+
	rcall	mirror8
	mov		r18, r17

	ld		r16, z+
	rcall	mirror8
	mov		r19, r17

	ld		r16, z+
	rcall	mirror8
	mov		r20, r17

	ld		r16, z+
	rcall	mirror8

	sbiw	zl, 4
	st		z+, r17
	st		z+, r20
	st		z+, r19
	st		z+, r18

	ret

reset:
	ldi		r16, low(RAMEND)
	out		SPL, r16
	ldi		r16, high(RAMEND)
	out		SPH, r16

	ldi		r16, 0xAA
	sts		data, r16
	ldi		r16, 0x55
	sts		data+1, r16
	ldi		r16, 0x18
	sts		data+2, r16
	ldi		r16, 0xC3
	sts		data+3, r16

	ldi		zl, low(data)
	ldi		zh, high(data)
	rcall	mirror32

loop:
	rjmp	loop

.dseg
data:	.byte 4