Changes between Version 7 and Version 8 of kernel_syscalls

Timestamp:

Oct 28, 2014, 8:13:36 PM (10 years ago)

Author:

alain

Comment:

--

kernel_syscalls

@@ -5 +5 @@
 [[PageOutline]]
 
-The [source:soft/giet_vm/giet_kernel/sys_handler.c _syscall_vector] array contains the 64 kernel functions defined by the GIET-VM to handle system calls. Most of these functions are provided by the peripheral drivers,
-but some services are provided by the kernel itself:
+The [source:soft/giet_vm/giet_kernel/sys_handler.c _syscall_vector] array contains the 64 kernel functions (syscal handlers) defined by the GIET-VM to handle system calls.
+
+== __Miscelaneous syscall handlers__ ==
 
 === void '''_sys_ukn'''() ===
 Function executed in case of undefined syscall
 
-=== void '''_proc_xyp'''( unsigned int* x,  unsigned int*,   unsigned int* p ) ===
+=== void '''_sys_proc_xyp'''( unsigned int* x,  unsigned int*,   unsigned int* p ) ===
 This function returns the processor (x,y,p) identifiers.
 
-=== int '''_call_timer_start'''( unsigned int period ) ===
+== __TTY related syscall handlers__ ==
+
+=== int '''_sys_tty_alloc'''() ===
+
+=== int '''_sys_tty_write'''( const char*  buffer,  unsigned int length,  unsigned int channel ) ===  
+This non-blocking function writes a character string from a fixed-length buffer to a TTY terminal identified by the channel argument. If channel argument is 0xFFFFFFFF, the TTY index is found in the task context. 
+It is non blocking: it tests the TTY_STATUS register, and stops the transfer as soon as the TTY_STATUS[WRITE] bit is set. Returns  the number of characters that have been written.
+
+=== int '''_sys_tty_read'''(  char* buffer,  unsigned int length,  unsigned int channel ) === 
+This non-blocking function fetches one character from the terminal identified by the channel argument. If the channel argument is 0xFFFFFFFF, the channel index is obtained from the current task context. 
+It uses the TTY_GET_IRQ[tty_id] interrupt and the buffer must have been filled by the TTY_ISR.
+It test the _tty_rx_full[tty_id] variable, read the _tty_rx_buf[tty_id] buffer, writes this character to the target buffer, and resets the_tty_rx_full[tty_id] register. The length argument is not used.
+Returns  the number of characters that have been read (0/1).
+
+=== void '''_sys_tty_get_lock'''( unsigned int  channel,   unsigned int* save_sr_ptr ) ===
+This blocking function try to take the lock protecting exclusive access to TTY terminal identified by the "channel" argument.
+It enters a critical section before taking the lock, and save the SR value at address defined by the ''save_sr_ptr'' argument.
+It returns only when the lock has been successfully taken.
+
+=== void '''_sys_tty_release_lock'''( unsigned int  channel,  unsigned int* save_sr_ptr ) ===
+This function releases the lock protecting exclusive access to TTY terminal identified by the channel argument.
+It exit the critical section after lock release, and restore SR value from address defined by the ''save_sr_ptr'' argument.
+
+== __TIM retated syscall handlers__ ==
+
+=== int '''_sys_timer_alloc'''() ===
+This function allocates a private timer to the calling task, and register the timer index in the task context.
+Return -1 if no timer available.
+
+=== int '''_sys_timer_start'''( unsigned int period ) ===
 This function starts the user timer channel allocated to the calling task.
+Returns -1 if no allocated timer.
 
-=== int '''_call_timer_stop'''( unsigned int period ) ===
+=== int '''_sys_timer_stop'''() ===
 This function stops the user timer channel allocated to the calling task.
+Returns -1 if no allocated timer.
 
 === void '''_task_exit'''() ===