pSOSystem System Calls - Read

t_restart pSOS+ System Calls
Target
Startup Values
At the start of the task, the CPU registers and the stack are initialized in such a way
that if the outermost function of the task exits by mistake, an illegal error address
results. The contents of the original registers and stack are platform-specific:
960
PPC
ARM
x86
Return Value
On 960 processors, the return address (RIP) on the stack is
0xDEADDEAD.
On PowerPC and ARM processors, the return address in register LR is
0xDEADDEAD.
On x86 processors, the return address on the stack is 0xFFFFFFFF.
A restarted task can receive up to four long words of input arguments. To facilitate
retrieval of these arguments, they are passed to the task as if it is invoked as a highlevel
language procedure or function. For example, if a C task nice has three input
arguments, it can be declared as follows:
nice (unsigned long a, unsigned long b, unsigned long c);
where targs[0]is passed to a, targs[1]to b, and targs[2] to c. In this case,
targs[3]is irrelevant and does not need the calling task to load it.
This system call returns 0 on success, or an error code on failure.
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