.syntax unified
    .cpu cortex-a7
    .thumb
    @ maze entry logger: ring-buffer of (lr,sp) at 0x08006964 (8 slots),
    @ return 0. Guard: bad lr spins with IRQs off.
    .text
    .global maze_stub
maze_stub:
    movw r12, #:lower16:0x08006964
    movt r12, #:upper16:0x08006964
    ldr r12, [r12, #28]       @ idx
    add r12, #1
    and r12, #7
    str r12, [r12, #-28]      @ hmm placeholder, replaced below
    movs r0, #0
    bx lr