trampoline.s

// Call with x0 = hbabi, x1 = 0xFFFFFFFFFFFFFFFF, x2 = NRO address
// Starts running the NRO. Returns the exit code of the homebrew.
nroEntrypointTrampoline:

    // TODO: Ideally, set up a new stack so NRO has a full stack to work with.

    // Save r19-r29
    stp x19, x20, [sp,-0x10]!
    stp x21, x22, [sp,-0x10]!
    stp x23, x24, [sp,-0x10]!
    stp x25, x26, [sp,-0x10]!
    stp x27, x28, [sp,-0x10]!
    stp x29, x30, [sp,-0x10]!
    
    // Call NRO.
    blr  x2

    // Restore r19-r29
    ldp x29, x30, [sp], 0x10
    ldp x27, x28, [sp], 0x10
    ldp x25, x26, [sp], 0x10
    ldp x23, x24, [sp], 0x10
    ldp x21, x22, [sp], 0x10
    ldp x19, x20, [sp], 0x10

    // TODO: Ideally, reset old stack pointer
    ret