/* FreeRTOS V7.1.0 - Copyright (C) 2011 Real Time Engineers Ltd. *************************************************************************** * * * FreeRTOS tutorial books are available in pdf and paperback. * * Complete, revised, and edited pdf reference manuals are also * * available. * * * * Purchasing FreeRTOS documentation will not only help you, by * * ensuring you get running as quickly as possible and with an * * in-depth knowledge of how to use FreeRTOS, it will also help * * the FreeRTOS project to continue with its mission of providing * * professional grade, cross platform, de facto standard solutions * * for microcontrollers - completely free of charge! * * * * >>> See http://www.FreeRTOS.org/Documentation for details. <<< * * * * Thank you for using FreeRTOS, and 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 modification 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. */ #include .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, -120 # 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) # preserve the errno call __errno # get the errno pointer ldw r3, 0(r2) # load the errno in r3 stw r3, 116(sp) # store the errno on the stack save_sp_to_pxCurrentTCB: call xTaskGetSchedulerState # Only save the stack if scheduler has been started beq r2, zero, hw_irq_test # If xTaskGetSchedulerState returns 0 it has not been started yet 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: call xTaskGetSchedulerState # Only restore stack if scheduler has been started beq r2, zero, restore_context # If xTaskGetSchedulerState returns 0 it has not been started yet 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: # preserve the errno call __errno # get the errno pointer ldw r3, 116(sp) # get errno from the stack stw r3, 0(r2) # restore the global errno for this task ldw ra, 0(sp) # Restore the registers. # Leave a gap for muldiv 0. ldw at, 8(sp) ldw r2, 12(sp) # now restore r2 from the stack 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, 120 # 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 #ifdef ALT_INCLUDE_INSTRUCTION_RELATED_EXCEPTION_API mov r4, ea # load the PC of the exception into r4 call alt_instruction_exception_entry # call the invalid instruction parser and bring up the instruction in the callback #else break # This is an un-implemented instruction or muldiv problem. #endif br restore_context # its something else call_scheduler: call xTaskGetSchedulerState # Only restore stack if scheduler has been started beq r2, zero, restore_context # If xTaskGetSchedulerState returns 0 it has not been started yet 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.