2 FreeRTOS V7.6.0 - Copyright (C) 2013 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS provides completely free yet professionally developed, *
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10 * robust, strictly quality controlled, supported, and cross *
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11 * platform software that has become a de facto standard. *
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13 * Help yourself get started quickly and support the FreeRTOS *
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14 * project by purchasing a FreeRTOS tutorial book, reference *
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15 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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19 ***************************************************************************
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21 This file is part of the FreeRTOS distribution.
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23 FreeRTOS is free software; you can redistribute it and/or modify it under
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24 the terms of the GNU General Public License (version 2) as published by the
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25 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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27 >>! NOTE: The modification to the GPL is included to allow you to distribute
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28 >>! a combined work that includes FreeRTOS without being obliged to provide
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29 >>! the source code for proprietary components outside of the FreeRTOS
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32 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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33 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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34 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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35 link: http://www.freertos.org/a00114.html
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39 ***************************************************************************
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41 * Having a problem? Start by reading the FAQ "My application does *
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42 * not run, what could be wrong?" *
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44 * http://www.FreeRTOS.org/FAQHelp.html *
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46 ***************************************************************************
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48 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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49 license and Real Time Engineers Ltd. contact details.
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51 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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52 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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53 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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55 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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56 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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57 licenses offer ticketed support, indemnification and middleware.
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59 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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60 engineered and independently SIL3 certified version for use in safety and
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61 mission critical applications that require provable dependability.
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66 .extern vTaskSwitchContext
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70 # Exported to start the first task.
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71 .globl restore_sp_from_pxCurrentTCB
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73 # Entry point for exceptions.
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74 .section .exceptions.entry, "xa"
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76 # Save the entire context of a task.
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78 addi ea, ea, -4 # Point to the next instruction.
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79 addi sp, sp, -116 # Create space on the stack.
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81 # Leave a gap for muldiv 0
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97 rdctl r5, estatus # Save the eStatus
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99 stw ea, 72(sp) # Save the PC
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100 stw r16, 76(sp) # Save the remaining registers
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111 save_sp_to_pxCurrentTCB:
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112 movia et, pxCurrentTCB # Load the address of the pxCurrentTCB pointer
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113 ldw et, (et) # Load the value of the pxCurrentTCB pointer
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114 stw sp, (et) # Store the stack pointer into the top of the TCB
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116 .section .exceptions.irqtest, "xa"
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119 * Test to see if the exception was a software exception or caused
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120 * by an external interrupt, and vector accordingly.
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122 rdctl r4, ipending # Load the Pending Interrupts indication
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123 rdctl r5, estatus # Load the eStatus (enabled interrupts).
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124 andi r2, r5, 1 # Are interrupts enabled globally.
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125 beq r2, zero, soft_exceptions # Interrupts are not enabled.
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126 beq r4, zero, soft_exceptions # There are no interrupts triggered.
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128 .section .exceptions.irqhandler, "xa"
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130 call alt_irq_handler # Call the alt_irq_handler to deliver to the registered interrupt handler.
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132 .section .exceptions.irqreturn, "xa"
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133 restore_sp_from_pxCurrentTCB:
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134 movia et, pxCurrentTCB # Load the address of the pxCurrentTCB pointer
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135 ldw et, (et) # Load the value of the pxCurrentTCB pointer
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136 ldw sp, (et) # Load the stack pointer with the top value of the TCB
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139 ldw ra, 0(sp) # Restore the registers.
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140 # Leave a gap for muldiv 0.
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156 ldw et, 68(sp) # Load the eStatus
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157 wrctl estatus, et # Write the eStatus
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158 ldw ea, 72(sp) # Load the Program Counter
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169 addi sp, sp, 116 # Release stack space
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171 eret # Return to address ea, loading eStatus into Status.
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173 .section .exceptions.soft, "xa"
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175 ldw et, 0(ea) # Load the instruction where the interrupt occured.
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176 movhi at, %hi(0x003B683A) # Load the registers with the trap instruction code
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177 ori at, at, %lo(0x003B683A)
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178 cmpne et, et, at # Compare the trap instruction code to the last excuted instruction
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179 beq et, r0, call_scheduler # its a trap so switchcontext
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180 break # This is an un-implemented instruction or muldiv problem.
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181 br restore_context # its something else
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184 addi ea, ea, 4 # A trap was called, increment the program counter so it is not called again.
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185 stw ea, 72(sp) # Save the new program counter to the context.
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186 call vTaskSwitchContext # Pick the next context.
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187 br restore_sp_from_pxCurrentTCB # Switch in the task context and restore.
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