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kernel/critsec.c File Reference

#include "config.h"
#include <sys/critsec.h>
#include <unistd.h>
#include <sys/tm.h>
#include <tm.h>

Include dependency graph for critsec.c:

Include dependency graph

Go to the source code of this file.

Functions

int locked_check_and_increment (atomic_t *counter, tdata_t **tid)
 check and increment counter, without interruptions

 __asm__ ("\n\.text\n\.global _locked_check_and_increment\n\_locked_check_and_increment:\n\push.w r4\n\stc ccr, r4h\n\orc#0x80, ccr\n\mov.b @r0, r4l\n\beq lci_get_lock\n\\n\push.w r2\n\push.w r3\n\mov.w @_ctid, r2\n\mov.w @r1, r3\n\sub.w r3, r2\n\bne lci_cant_lock\n\\n\pop.w r3\n\pop.w r2\n\bra lci_get_lock\n\\n\lci_cant_lock:\n\pop.w r3\n\pop.w r2\n\mov.w#0xffff, r0\n\bra lci_done\n\\n\lci_get_lock:\n\inc r4l\n\mov.b r4l,@r0\n\mov.w @_ctid, r0\n\mov.w r0,@r1\n\sub.w r0, r0\n\\n\lci_done:\n\ldc r4h, ccr\n\pop.w r4\n\rts\n\")
wakeup_t wait_critical_section (wakeup_t data)
 wakeup when critical section is available

int enter_critical_section (critsec_t *cs)
 enter critical section


Variables

atomic_t kernel_critsec_count
 critical section counter for kernel/task manager

Function Documentation

__asm__ (  "\n\.text\n\.global _locked_check_and_increment\n\_locked_check_and_increment:\n\push.w r4\n\stc  ccr,
r4h\n\orc#  0x80,
ccr\n\mov.b @  r0,
r4l\n\beq lci_get_lock\n\\n\push.w r2\n\push.w r3\n\mov.w @  _ctid,
r2\n\mov.w @  r1,
r3\n\sub.w  r3,
r2\n\bne lci_cant_lock\n\\n\pop.w r3\n\pop.w r2\n\bra lci_get_lock\n\\n\lci_cant_lock:\n\pop.w r3\n\pop.w r2\n\mov.w#  0xffff,
r0\n\bra lci_done\n\\n\lci_get_lock:\n\inc r4l\n\mov.b  r4l,
@r0\n\mov.w @  _ctid,
r0\n\mov.w  r0,
@r1\n\sub.w  r0,
r0\n\\n\lci_done:\n\ldc  r4h,
ccr\n\pop.w r4\n\rts\n\" 
) 
 

int enter_critical_section (  critsec_t *  cs  ) 
 

enter critical section

check and lock critical section if it is available; otherwise, wait until it is available, then lock it.

Parameters:
cs pointer to critical section (critsec_t)
Returns:
1 if successful, 0 upon failure
See also:
initialize_critical_section

leave_critical_section

destroy_critical_section

Definition at line 96 of file critsec.c.

int locked_check_and_increment (  atomic_t *  counter,
tdata_t **  tid
) 
 

check and increment counter, without interruptions

increments counter if count is already zero, or if this is the same task as the one that made it one.

used to enter a normal critical section.

Parameters:
counter pointer to counter to be incremented
tid pointer to pointer to receive task pointer of the task that has locked the resource
Returns:
0xffff if failure, 0 if successful
See also:
locked_decrement

wakeup_t wait_critical_section (  wakeup_t  data  ) 
 

wakeup when critical section is available

wakeup function used to detect when a critical section is available. called while processing an interrupt, so interrupts are already disabled.

Definition at line 78 of file critsec.c.

Referenced by enter_critical_section().

Variable Documentation

atomic_t kernel_critsec_count
 

critical section counter for kernel/task manager

when the critical section counter is Zero, task swapping is allowed. when greater than zero, task swapping is not allowed. This is checked in the task_switch_handler() in systime.c

Definition at line 17 of file critsec.c.

brickOS is released under the Mozilla Public License.
Original code copyright 1998-2002 by the authors.
Generated on Mon Feb 16 21:02:27 2004 for brickOS Kernel Developer by doxygen 1.3.5