bde2109b7c
IPC changes: - receive() is changed to take an additional parameter, which is a pointer to a status code. - The status code is filled in by the kernel to provide additional information to the caller. For now, the kernel only fills in the IPC call used by the sender. Syslib changes: - sef_receive() has been split into sef_receive() (with the original semantics) and sef_receive_status() which exposes the status code to userland. - Ideally, every sys process should gradually switch to sef_receive_status() and use is_ipc_notify() as a dependable way to check for notify. - SEF has been modified to use is_ipc_notify() and demonstrate how to use the new status code.
43 lines
1.3 KiB
C
43 lines
1.3 KiB
C
#include "sysutil.h"
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#include <timers.h>
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/*===========================================================================*
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* tickdelay *
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*===========================================================================*/
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PUBLIC int tickdelay(ticks)
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long ticks; /* number of ticks to wait */
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{
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/* This function uses the synchronous alarm to delay for a while. This works
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* even if a previous synchronous alarm was scheduled, because the remaining
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* tick of the previous alarm are returned so that it can be rescheduled.
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* Note however that a long tick_delay (longer than the remaining time of the
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* previous) alarm will also delay the previous alarm.
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*/
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message m, m_alarm;
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int s;
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if (ticks <= 0) return OK; /* check for robustness */
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m.ALRM_EXP_TIME = ticks; /* request message after ticks */
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m.ALRM_ABS_TIME = 0; /* ticks are relative to now */
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s = _kernel_call(SYS_SETALARM, &m);
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if (s != OK) return(s);
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sef_receive(CLOCK,&m_alarm); /* await synchronous alarm */
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/* Check if we must reschedule the current alarm. */
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if (m.ALRM_TIME_LEFT > 0 && m.ALRM_TIME_LEFT != TMR_NEVER) {
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m.ALRM_EXP_TIME = m.ALRM_TIME_LEFT - ticks;
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if (m.ALRM_EXP_TIME <= 0)
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m.ALRM_EXP_TIME = 1;
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s = _kernel_call(SYS_SETALARM, &m);
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}
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return(s);
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}
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