ref: 2f4c39ec2bf7a5eb84ed1a7c810a0a85b2e47cd0 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)