kernel/systime.c File Reference

Implementation: system time services. More...

#include <config.h>
#include <sys/time.h>
#include <sys/h8.h>
#include <sys/irq.h>
#include <sys/dmotor.h>
#include <sys/dsound.h>
#include <sys/battery.h>
#include <sys/critsec.h>
#include <sys/timeout.h>

Include dependency graph for systime.c:

Go to the source code of this file.

Functions
void	clock_handler (void)
	clock handler triggered on the WDT overflow (every msec) on the NMI
void	subsystem_handler (void)
	subsystem handler for every 2nd msec
void	task_switch_handler (void)
	task switch handler called every msec
void	systime_init (void)
	initialize system timer
void	systime_shutdown (void)
	shutdown system timer
void	systime_set_switcher (void *switcher)
	set task switcher vector
void	systime_set_timeslice (unsigned char slice)
	set multitasking timeslice in ms
time_t	get_system_up_time (void)
	retrieve the current system time
	__asm__ ("\n\.text\n\.align 1\n\.global _get_system_up_time\n\_get_system_up_time:\n\push r2\n\try_again:\n\mov.w @_sys_time+2, r1\n\mov.w @_sys_time, r0\n\mov.w @_sys_time+2, r2\n\cmp r2, r1\n\bne try_again\n\pop r2\n\rts\n\")
Variables
volatile time_t	sys_time
	current system time in ms
volatile unsigned char	tm_timeslice
	task time slice
volatile unsigned char	tm_current_slice
	current time remaining
void *	tm_switcher_vector
	pointer to task switcher

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Detailed Description

Implementation: system time services.

Author:

Markus L. Noga <markus@noga.de>

Definition in file systime.c.

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Function Documentation

__asm__ (  "\n\.text\n\.align 1\n\.global _get_system_up_time\n\_get_system_up_time:\n\push r2\n\try_again:\n\mov.w @_sys_time+  2, r1\n\mov.w @  _sys_time, r0\n\mov.w @_sys_time+  2, r2\n\cmp  r2, r1\n\bne try_again\n\pop r2\n\rts\n\"  )

void clock_handler (  void   )

clock handler triggered on the WDT overflow (every msec) on the NMI this is the system clock Referenced by systime_init().

time_t get_system_up_time (  void   )

retrieve the current system time Returns: number of msecs the system has been running Since sys_time is 32bits, it takes more than one instruction to retrieve; the NMI can fire mid retrieval; causing the upper and lower 16bits to be unmatched (lower 16bits could overflow and reset to 0, while upper 16bits were already read)

void subsystem_handler (  void   )

subsystem handler for every 2nd msec this is the pulse of the system (subsystems). sound, motor and lcd driver calls are initiated here. task_switch_handler is called from here as well. Referenced by systime_init().

void systime_init (  void   )

initialize system timer task switcher initialized to empty handler motors turned off Definition at line 270 of file systime.c. References clock_handler(), dm_shutdown(), nmi_vector, ocia_vector, ocib_vector, rom_dummy_handler(), subsystem_handler(), sys_time, systime_shutdown(), T_CR, T_CSR, T_IER, T_OCR, T_OCRA, T_OCRB, task_switch_handler(), TCR_CLOCK_32, TCSR_RESET_ON_A, TIER_ENABLE_OCA, TIER_ENABLE_OCB, tm_current_slice, TM_DEFAULT_SLICE, tm_switcher_vector, tm_timeslice, TOCR_OCRA, TOCR_OCRB, WDT_CNT_MSEC_64, WDT_CNT_PASSWORD, WDT_CSR, WDT_CSR_CLOCK_64, WDT_CSR_ENABLE, WDT_CSR_MODE_WATCHDOG, WDT_CSR_PASSWORD, and WDT_CSR_WATCHDOG_NMI.

void systime_set_switcher (  void *  switcher  )

set task switcher vector Parameters: switcher  the switcher Definition at line 326 of file systime.c. References tm_switcher_vector.

void systime_set_timeslice (  unsigned char  slice  )

set multitasking timeslice in ms Parameters: slice  the timeslice. must be at least 5ms. Definition at line 333 of file systime.c. References tm_current_slice, and tm_timeslice.

void systime_shutdown (  void   )

shutdown system timer will also stop task switching and motors. Definition at line 317 of file systime.c. References T_IER, TIER_ENABLE_OCA, TIER_ENABLE_OCB, WDT_CSR, and WDT_CSR_ENABLE. Referenced by systime_init().

void task_switch_handler (  void   )

task switch handler called every msec handles swapping between tasks Referenced by systime_init().

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Variable Documentation

volatile time_t sys_time

current system time in ms Warning: This is a 32 bit value which will overflow after 49.7 days of continuous operation. Definition at line 63 of file systime.c. Referenced by systime_init().

volatile unsigned char tm_current_slice

current time remaining Definition at line 73 of file systime.c. Referenced by systime_init(), and systime_set_timeslice().

void* tm_switcher_vector

pointer to task switcher Definition at line 75 of file systime.c. Referenced by systime_init(), and systime_set_switcher().

volatile unsigned char tm_timeslice

task time slice Definition at line 72 of file systime.c. Referenced by systime_init(), and systime_set_timeslice().

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brickOS is released under the Mozilla Public License. Original code copyright 1998-2002 by the authors.

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