ref: c02de4e9e2b13f0b951ba05c2c9b9f6d1c2a2673 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)