#### 21.4.6 Cell Broadband Engine SPU architecture

When gdb is debugging the Cell Broadband Engine SPU architecture, it provides the following special commands:

`info spu event`
  Display SPU event facility status. Shows current event mask and pending event status.
`info spu signal`
  Display SPU signal notification facility status. Shows pending signal-control word and signal notification mode of both signal notification channels.
`info spu mailbox`
  Display SPU mailbox facility status. Shows all pending entries, in order of processing, in each of the SPU Write Outbound, SPU Write Outbound Interrupt, and SPU Read Inbound mailboxes.
`info spu dma`
  Display MFC DMA status. Shows all pending commands in the MFC DMA queue. For each entry, opcode, tag, class IDs, effective and local store addresses and transfer size are shown.
`info spu proxydma`
  Display MFC Proxy-DMA status. Shows all pending commands in the MFC Proxy-DMA queue. For each entry, opcode, tag, class IDs, effective and local store addresses and transfer size are shown.

When gdb is debugging a combined PowerPC/SPU application on the Cell Broadband Engine, it provides in addition the following special commands:

`set spu stop-on-load` arg
  Set whether to stop for new SPE threads. When set to `on`, gdb will give control to the user when a new SPE thread enters its `main` function. The default is `off`.
`show spu stop-on-load`
  Show whether to stop for new SPE threads.
`set spu auto-flush-cache` arg
  Set whether to automatically flush the software-managed cache. When set to `on`, gdb will automatically cause the SPE software-managed cache to be flushed whenever SPE execution stops. This provides a consistent view of PowerPC memory that is accessed via the cache. If an application does not use the software-managed cache, this option has no effect.
`show spu auto-flush-cache`
  Show whether to automatically flush the software-managed cache.