ref: 85d0f0e1a2c05afee5a101c1e51a3ddd2ff2a5f6 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)