===== 09 FSI FU SIO RXEN IMASK | BIOS 19951204 System ROM Version 3.0 11/18/96 A
BadVaddr as the group starts: 800154CE
Controller port with RXEN and no device selected (JOY_CTRL bit 1 clear), slot 1.
CTRL 0004, no data written; JOY_STAT (bits 0-10) every 100 cycles from 0 to 3000:
  005 005 005 005 005 005 005 005 005 005 005 005 005 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007
  bytes in the RX FIFO: 1 FF; I_STAT bit 7 then 0
CTRL 0805, no data written; JOY_STAT (bits 0-10) every 100 cycles from 0 to 3000:
  005 005 005 005 005 005 005 005 005 005 005 005 005 207 207 207 207 207 207 207 207 207 207 207 207 207 207 207 207 207 207
  bytes in the RX FIFO: 1 FF; I_STAT bit 7 then 1
I_MASK's upper half (the console read 960507FFh after sw FFFFFFFFh, chainb/028/01IMR.txt:4):
sw 12345678h to I_MASK, lw at once: AD090678
sw 12345678h, lui/ori of CAFEBABEh, then lw: AD090678
sw 12345678h, lw of I_STAT and a nop, then lw: AE020678
I_MASK back to 00000009
Done.