ref: a945c6f5b1f69b9bf7a6a3a5404b14b9fe6c5e5c dir: /sys/src/9/bcm64/init9.s/
TEXT main(SB), 1, $8 MOV $setSB(SB), R28 /* load the SB */ MOV $boot(SB), R0 B startboot(SB)