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https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/baremetal/arch/aarch64/semihost_exit.S[baremetal/arch/aarch64/semihost_exit.S]

``
.global main
main:
    /* 0x20026 == ADP_Stopped_ApplicationExit */
    mov x1, 0x26
    movk x1, 2, lsl 16
    str x1, [sp, 0]

    /* Exit status code. Host QEMU process exits with that status. */
    mov x0, 0
    str x0, [sp, 8]

    /* x1 contains the address of parameter block.
     * Any memory address could be used.
     */
    mov x1, sp

    /* SYS_EXIT */
    mov w0, 0x18

    /* Do the semihosting call on A64. */
    hlt 0xf000
``


Bare metal!