ref: bd773dee09460f5d77c96f2fe3d34ec5ee0b54ce dir: /sys/src/9/cycv/init9.s/
TEXT _main(SB), $-4 MOVW $setR12(SB), R12 MOVW 4(R13), R0 ADD $4, R13, R1 SUB $4, R13 MOVW R1, 8(R13) MOVW $startboot(SB), R15