pSOSystem System Calls - Read

t_start pSOS+ System Calls
Return Value
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.
User and Supervisor Modes
You use the symbolic constants T_USER and T_SUPV on each processor as follows:
960
x86
Interrupt Control
On 960 and x86 processors, a task can execute only in supervisor
mode. In , for these processors, the symbols T_SUPV and
T_USER are defined as:
#define T_SUPV 0
#define T_USER 0
for the sole purpose of compatibility with platforms that support both
user and supervisor modes.
Interrupt control means that while a task 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:
PPC
x86
MIPS
ARM
On PowerPC, x86, MIPS, and ARM processors, you can simply enable or
disable all hardware interrupts. You do this by placing either T_ISR or
T_NOISR in the mode argument.
This system call returns 0 on success, or an error code on failure.
1-160 pSOSystem System Calls