pSOSystem System Calls - Read

pSOS+ System Calls as_catch
Return Value
Error Codes
Notes
Interrupt Control
Interrupt control means that while an ASR is executing, hardware interrupts are
disabled. On some processors, you can disable all interrupts at or below a certain
interrupt level and enable all interrupts above that level. On other processors you
can simply specify that all interrupts are either enabled or disabled. Details are
provided below:
How Signals Are Passed to the ASR
The method by which signals are passed to the ASR is processor-specific:
68K
960
x86
On 68K processors, signals are passed to the ASR in the D0.L register.
On 960 processors, signals are passed to the ASR in the G0 register.
On x86 processors, signals are passed to the ASR in the EAX register.
This system call always returns 0.
This system call returns no errors.
1. An invalid ASR (for example, start_addr = 0) should not be confused with
the ASR attribute T_NOASR. If a task's ASR is invalid, then an as_send() call
directed to it will be rejected and returned with an error; whereas, the T_NOASR
attribute simply defers the ASR's execution, with any intervening signals sent to
it left pending.
2. A normal task would call as_catch() only once, and usually as part of its
initialization sequence. Before the first as_catch() call, a task is initialized by
the pSOS+ kernel to have an invalid ASR.
pSOSystem System Calls 1-5
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