| /* | |
| FreeRTOS V6.1.1 - Copyright (C) 2011 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 books - available as PDF or paperback * | |
| * * | |
| * "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. | |
| */ | |
| #include "FreeRTOSConfig.h" | |
| #define portCONTEXT_SIZE 132 | |
| #define portEPC_STACK_LOCATION 124 | |
| #define portSTATUS_STACK_LOCATION 128 | |
| /******************************************************************/ | |
| .macro portSAVE_CONTEXT | |
| /* Make room for the context. First save the current status so we can | |
| manipulate it, and the cause and EPC registers so we capture their | |
| original values in case of interrupt nesting. */ | |
| mfc0 k0, _CP0_CAUSE | |
| addiu sp, sp, -portCONTEXT_SIZE | |
| mfc0 k1, _CP0_STATUS | |
| /* Also save s6 and s5 so we can use them during this interrupt. Any | |
| nesting interrupts should maintain the values of these registers | |
| across the ISR. */ | |
| sw s6, 44(sp) | |
| sw s5, 40(sp) | |
| sw k1, portSTATUS_STACK_LOCATION(sp) | |
| /* Enable interrupts above the current priority. */ | |
| srl k0, k0, 0xa | |
| ins k1, k0, 10, 6 | |
| ins k1, zero, 1, 4 | |
| /* s5 is used as the frame pointer. */ | |
| add s5, zero, sp | |
| /* Check the nesting count value. */ | |
| la k0, uxInterruptNesting | |
| lw s6, (k0) | |
| /* If the nesting count is 0 then swap to the the system stack, otherwise | |
| the system stack is already being used. */ | |
| bne s6, zero, .+20 | |
| nop | |
| /* Swap to the system stack. */ | |
| la sp, xISRStackTop | |
| lw sp, (sp) | |
| /* Increment and save the nesting count. */ | |
| addiu s6, s6, 1 | |
| sw s6, 0(k0) | |
| /* s6 holds the EPC value, this is saved after interrupts are re-enabled. */ | |
| mfc0 s6, _CP0_EPC | |
| /* Re-enable interrupts. */ | |
| mtc0 k1, _CP0_STATUS | |
| /* Save the context into the space just created. s6 is saved again | |
| here as it now contains the EPC value. No other s registers need be | |
| saved. */ | |
| sw ra, 120(s5) | |
| sw s8, 116(s5) | |
| sw t9, 112(s5) | |
| sw t8, 108(s5) | |
| sw t7, 104(s5) | |
| sw t6, 100(s5) | |
| sw t5, 96(s5) | |
| sw t4, 92(s5) | |
| sw t3, 88(s5) | |
| sw t2, 84(s5) | |
| sw t1, 80(s5) | |
| sw t0, 76(s5) | |
| sw a3, 72(s5) | |
| sw a2, 68(s5) | |
| sw a1, 64(s5) | |
| sw a0, 60(s5) | |
| sw v1, 56(s5) | |
| sw v0, 52(s5) | |
| sw s6, portEPC_STACK_LOCATION(s5) | |
| sw $1, 16(s5) | |
| /* s6 is used as a scratch register. */ | |
| mfhi s6 | |
| sw s6, 12(s5) | |
| mflo s6 | |
| sw s6, 8(s5) | |
| /* Update the task stack pointer value if nesting is zero. */ | |
| la s6, uxInterruptNesting | |
| lw s6, (s6) | |
| addiu s6, s6, -1 | |
| bne s6, zero, .+20 | |
| nop | |
| /* Save the stack pointer. */ | |
| la s6, uxSavedTaskStackPointer | |
| sw s5, (s6) | |
| .endm | |
| /******************************************************************/ | |
| .macro portRESTORE_CONTEXT | |
| /* Restore the stack pointer from the TCB. This is only done if the | |
| nesting count is 1. */ | |
| la s6, uxInterruptNesting | |
| lw s6, (s6) | |
| addiu s6, s6, -1 | |
| bne s6, zero, .+20 | |
| nop | |
| la s6, uxSavedTaskStackPointer | |
| lw s5, (s6) | |
| /* Restore the context. */ | |
| lw s6, 8(s5) | |
| mtlo s6 | |
| lw s6, 12(s5) | |
| mthi s6 | |
| lw $1, 16(s5) | |
| /* s6 is loaded as it was used as a scratch register and therefore saved | |
| as part of the interrupt context. */ | |
| lw s6, 44(s5) | |
| lw v0, 52(s5) | |
| lw v1, 56(s5) | |
| lw a0, 60(s5) | |
| lw a1, 64(s5) | |
| lw a2, 68(s5) | |
| lw a3, 72(s5) | |
| lw t0, 76(s5) | |
| lw t1, 80(s5) | |
| lw t2, 84(s5) | |
| lw t3, 88(s5) | |
| lw t4, 92(s5) | |
| lw t5, 96(s5) | |
| lw t6, 100(s5) | |
| lw t7, 104(s5) | |
| lw t8, 108(s5) | |
| lw t9, 112(s5) | |
| lw s8, 116(s5) | |
| lw ra, 120(s5) | |
| /* Protect access to the k registers, and others. */ | |
| di | |
| /* Decrement the nesting count. */ | |
| la k0, uxInterruptNesting | |
| lw k1, (k0) | |
| addiu k1, k1, -1 | |
| sw k1, 0(k0) | |
| lw k0, portSTATUS_STACK_LOCATION(s5) | |
| lw k1, portEPC_STACK_LOCATION(s5) | |
| /* Leave the stack how we found it. First load sp from s5, then restore | |
| s5 from the stack. */ | |
| add sp, zero, s5 | |
| lw s5, 40(sp) | |
| addiu sp, sp, portCONTEXT_SIZE | |
| mtc0 k0, _CP0_STATUS | |
| ehb | |
| mtc0 k1, _CP0_EPC | |
| eret | |
| nop | |
| .endm | |