/* | |
FreeRTOS V6.0.0 - Copyright (C) 2009 Real Time Engineers Ltd. | |
*************************************************************************** | |
* * | |
* If you are: * | |
* * | |
* + New to FreeRTOS, * | |
* + Wanting to learn FreeRTOS or multitasking in general quickly * | |
* + Looking for basic training, * | |
* + Wanting to improve your FreeRTOS skills and productivity * | |
* * | |
* then take a look at the FreeRTOS eBook * | |
* * | |
* "Using the FreeRTOS Real Time Kernel - a Practical Guide" * | |
* http://www.FreeRTOS.org/Documentation * | |
* * | |
* A pdf reference manual is also available. Both are usually delivered * | |
* to your inbox within 20 minutes to two hours when purchased between 8am * | |
* and 8pm GMT (although please allow up to 24 hours in case of * | |
* exceptional circumstances). Thank you for your support! * | |
* * | |
*************************************************************************** | |
This file is part of the FreeRTOS distribution. | |
FreeRTOS is free software; you can redistribute it and/or modify it under | |
the terms of the GNU General Public License (version 2) as published by the | |
Free Software Foundation AND MODIFIED BY the FreeRTOS exception. | |
***NOTE*** The exception to the GPL is included to allow you to distribute | |
a combined work that includes FreeRTOS without being obliged to provide the | |
source code for proprietary components outside of the FreeRTOS kernel. | |
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT | |
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
more details. You should have received a copy of the GNU General Public | |
License and the FreeRTOS license exception along with FreeRTOS; if not it | |
can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
by writing to Richard Barry, contact details for whom are available on the | |
FreeRTOS WEB site. | |
1 tab == 4 spaces! | |
http://www.FreeRTOS.org - Documentation, latest information, license and | |
contact details. | |
http://www.SafeRTOS.com - A version that is certified for use in safety | |
critical systems. | |
http://www.OpenRTOS.com - Commercial support, development, porting, | |
licensing and training services. | |
*/ | |
.extern vTaskSwitchContext | |
.set noat | |
# Exported to start the first task. | |
.globl restore_sp_from_pxCurrentTCB | |
# Entry point for exceptions. | |
.section .exceptions.entry, "xa" | |
# Save the entire context of a task. | |
save_context: | |
addi ea, ea, -4 # Point to the next instruction. | |
addi sp, sp, -116 # Create space on the stack. | |
stw ra, 0(sp) | |
# Leave a gap for muldiv 0 | |
stw at, 8(sp) | |
stw r2, 12(sp) | |
stw r3, 16(sp) | |
stw r4, 20(sp) | |
stw r5, 24(sp) | |
stw r6, 28(sp) | |
stw r7, 32(sp) | |
stw r8, 36(sp) | |
stw r9, 40(sp) | |
stw r10, 44(sp) | |
stw r11, 48(sp) | |
stw r12, 52(sp) | |
stw r13, 56(sp) | |
stw r14, 60(sp) | |
stw r15, 64(sp) | |
rdctl r5, estatus # Save the eStatus | |
stw r5, 68(sp) | |
stw ea, 72(sp) # Save the PC | |
stw r16, 76(sp) # Save the remaining registers | |
stw r17, 80(sp) | |
stw r18, 84(sp) | |
stw r19, 88(sp) | |
stw r20, 92(sp) | |
stw r21, 96(sp) | |
stw r22, 100(sp) | |
stw r23, 104(sp) | |
stw gp, 108(sp) | |
stw fp, 112(sp) | |
save_sp_to_pxCurrentTCB: | |
movia et, pxCurrentTCB # Load the address of the pxCurrentTCB pointer | |
ldw et, (et) # Load the value of the pxCurrentTCB pointer | |
stw sp, (et) # Store the stack pointer into the top of the TCB | |
.section .exceptions.irqtest, "xa" | |
hw_irq_test: | |
/* | |
* Test to see if the exception was a software exception or caused | |
* by an external interrupt, and vector accordingly. | |
*/ | |
rdctl r4, ipending # Load the Pending Interrupts indication | |
rdctl r5, estatus # Load the eStatus (enabled interrupts). | |
andi r2, r5, 1 # Are interrupts enabled globally. | |
beq r2, zero, soft_exceptions # Interrupts are not enabled. | |
beq r4, zero, soft_exceptions # There are no interrupts triggered. | |
.section .exceptions.irqhandler, "xa" | |
hw_irq_handler: | |
call alt_irq_handler # Call the alt_irq_handler to deliver to the registered interrupt handler. | |
.section .exceptions.irqreturn, "xa" | |
restore_sp_from_pxCurrentTCB: | |
movia et, pxCurrentTCB # Load the address of the pxCurrentTCB pointer | |
ldw et, (et) # Load the value of the pxCurrentTCB pointer | |
ldw sp, (et) # Load the stack pointer with the top value of the TCB | |
restore_context: | |
ldw ra, 0(sp) # Restore the registers. | |
# Leave a gap for muldiv 0. | |
ldw at, 8(sp) | |
ldw r2, 12(sp) | |
ldw r3, 16(sp) | |
ldw r4, 20(sp) | |
ldw r5, 24(sp) | |
ldw r6, 28(sp) | |
ldw r7, 32(sp) | |
ldw r8, 36(sp) | |
ldw r9, 40(sp) | |
ldw r10, 44(sp) | |
ldw r11, 48(sp) | |
ldw r12, 52(sp) | |
ldw r13, 56(sp) | |
ldw r14, 60(sp) | |
ldw r15, 64(sp) | |
ldw et, 68(sp) # Load the eStatus | |
wrctl estatus, et # Write the eStatus | |
ldw ea, 72(sp) # Load the Program Counter | |
ldw r16, 76(sp) | |
ldw r17, 80(sp) | |
ldw r18, 84(sp) | |
ldw r19, 88(sp) | |
ldw r20, 92(sp) | |
ldw r21, 96(sp) | |
ldw r22, 100(sp) | |
ldw r23, 104(sp) | |
ldw gp, 108(sp) | |
ldw fp, 112(sp) | |
addi sp, sp, 116 # Release stack space | |
eret # Return to address ea, loading eStatus into Status. | |
.section .exceptions.soft, "xa" | |
soft_exceptions: | |
ldw et, 0(ea) # Load the instruction where the interrupt occured. | |
movhi at, %hi(0x003B683A) # Load the registers with the trap instruction code | |
ori at, at, %lo(0x003B683A) | |
cmpne et, et, at # Compare the trap instruction code to the last excuted instruction | |
beq et, r0, call_scheduler # its a trap so switchcontext | |
break # This is an un-implemented instruction or muldiv problem. | |
br restore_context # its something else | |
call_scheduler: | |
addi ea, ea, 4 # A trap was called, increment the program counter so it is not called again. | |
stw ea, 72(sp) # Save the new program counter to the context. | |
call vTaskSwitchContext # Pick the next context. | |
br restore_sp_from_pxCurrentTCB # Switch in the task context and restore. |