Changes between Version 3 and Version 4 of kernel_context

Timestamp:

Oct 20, 2014, 9:41:19 PM (10 years ago)

Author:

alain

Comment:

--

kernel_context

@@ -31 +31 @@
 || [5] $5    || [13] $13  || [21] $21  || [29] SP     || [37] LTID  || [45] CMA || [53] ***      ||
 || [6] $6    || [14] $14  || [22] $22  || [30] $30  || [38] VSID  || [46] GTID || [54] ***      ||   
-|| [7] $7    || [15] $15  || [23] $23  || [31] RA    | [39] PTPR   || [47] RUN  || [55] ***      ||
+|| [7] $7    || [15] $15  || [23] $23  || [31] RA    || [39] PTPR   || [47] RUN  || [55] ***      ||
 
+
+
+ === void _ctx_switch() ===
+This function performs a context switch between the running (calling) task and  another runable task, using a round-robin sheduling policy between all tasks allocated to a given processor (static allocation).
+It selects the next runable task to resume execution. 
+If the only runable task is the current task, return without context switch.
+If there is no runable task, the scheduler switch to the default "idle" task.
+The return address contained in $31 is saved in the current task context (in the ctx[31] slot), and the function actually returns to the address contained in the ctx[31] slot of the next task context.
+
+ === void _ctx_eret() ===
+The address of this function is used to initialise the return address in the "idle" task context.
+
+ === void _idle_task() ===
+This function is executed task when no other task can be executed.