ref: 1d0b9d7088f61fd3e28dada8e8e97abf3eac69f9 dir: /sys/src/9/arm64/init9.s/
TEXT main(SB), 1, $8 MOV $setSB(SB), R28 /* load the SB */ MOV $boot(SB), R0 B startboot(SB)