li x0, program_end ; x0 = start
li x1, 0xff ; x1 = end

mv x2, x0

loop_write:

xori x3, x2, 0xaaa
sw x3, 0(x2)
addi x2, x2, 1
ble x2, x1, loop_write

mv x2, x0

loop_read:

xori x3, x2, 0xaaa
lw x4, 0(x2)
bne x3, x4, error
addi x2, x2, 1
ble x2, x1, loop_read

success:

li x0, 0
wfi

error:

mv x0, x2
wfi

program_end: