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spu_run() - Unix, Linux System Call
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NAME
spu_run - execute an spu context
SYNOPSIS
int spu_run(int fd, unsigned int *npc, unsigned int *event); DESCRIPTION
The
spu_run system call is used on PowerPC machines that implement the
Cell Broadband Engine Architecture in order to access Synergistic
Processor Units (SPUs). It uses the
fd that was returned from
spu_create(2)
to address a specific SPU context. When the context gets scheduled
to a physical SPU, it starts execution at the instruction pointer
passed in
npc.
Execution of SPU code happens synchronously, meaning that
spu_run does not return while the SPU is still running. If there is a need
to execute SPU code in parallel with other code on either the
main CPU or other SPUs, you need to create a new thread of execution
first, e.g. using the
pthread_create(3)
call.
When
spu_run returns, the current value of the SPU instruction pointer is written
back to
npc, so you can call
spu_run again without updating the pointers.
event can be a NULL pointer or point to an extended status code that gets
filled when
spu_run returns. It can be one of the following constants:
| Tag | Description |
|---|
|
SPE_EVENT_DMA_ALIGNMENT | | |
A DMA alignment error
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SPE_EVENT_SPE_DATA_SEGMENT | | |
A DMA segmentation error
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SPE_EVENT_SPE_DATA_STORAGE | | |
A DMA storage error
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RETURN VALUE
spu_run returns the value of the
spu_status register or -1 to indicate an error and set errno to one
of the error codes listed below.
The
spu_status register value contains a bit mask of status codes and
optionally a 14 bit code returned from the
stop-and-signal instruction on the SPU. The bit masks for the status codes
are:
| Tag | Description |
|---|
|
0x02 |
SPU was stopped by
stop-and-signal. |
|
0x04 |
SPU was stopped by
halt. |
|
0x08 |
SPU is waiting for a channel.
|
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0x10 |
SPU is in single-step mode.
|
|
0x20 |
SPU has tried to execute an invalid instruction.
|
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0x40 |
SPU has tried to access an invalid channel.
|
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0x3fff0000 | | |
The bits masked with this value contain the code returned from
stop-and-signal. |
ERRORS
| Tag | Description |
|---|
|
EAGAIN or EWOULDBLOCK | | |
fd is in non-blocking mode and
spu_run would block.
|
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EBADF |
fd is not a valid file descriptor.
|
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EFAULT |
npc is not a valid pointer or
status is neither NULL nor a valid pointer.
|
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EINTR |
A signal occured while
spu_run was in progress. The
npc value has been updated to the new program counter value if
necessary.
|
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EINVAL |
fd is not a file descriptor returned from
spu_create(2).
|
|
ENOMEM |
Insufficient memory was available to handle a page fault
resulting from an MFC direct memory access.
|
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ENOSYS |
the functionality is not provided by the current system, because
either the hardware does not provide SPUs or the
spufs module is not loaded.
|
NOTES
spu_run is meant to be used from libraries that implement a more abstract
interface to SPUs, not to be used from regular applications.
CONFORMING TO
This call is Linux specific and only implemented by the ppc64
architecture. Programs using this system call are not portable.
BUGS
The code does not yet fully implement all features lined out here.
AUTHOR
Arnd Bergmann <arndb@de.ibm.com>
SEE ALSO
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