| ;/* |
| ; * FreeRTOS Kernel <DEVELOPMENT BRANCH> |
| ; * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved. |
| ; * |
| ; * SPDX-License-Identifier: MIT |
| ; * |
| ; * Permission is hereby granted, free of charge, to any person obtaining a copy of |
| ; * this software and associated documentation files (the "Software"), to deal in |
| ; * the Software without restriction, including without limitation the rights to |
| ; * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of |
| ; * the Software, and to permit persons to whom the Software is furnished to do so, |
| ; * subject to the following conditions: |
| ; * |
| ; * The above copyright notice and this permission notice shall be included in all |
| ; * copies or substantial portions of the Software. |
| ; * |
| ; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| ; * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS |
| ; * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR |
| ; * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER |
| ; * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
| ; * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| ; * |
| ; * https://www.FreeRTOS.org |
| ; * https://github.com/FreeRTOS |
| ; * |
| ; */ |
| |
| .text |
| .arm |
| .ref vTaskSwitchContext |
| .ref xTaskIncrementTick |
| .ref ulTaskHasFPUContext |
| .ref pxCurrentTCB |
| |
| ;/*-----------------------------------------------------------*/ |
| ; |
| ; Save Task Context |
| ; |
| portSAVE_CONTEXT .macro |
| DSB |
| |
| ; Push R0 as we are going to use it |
| STMDB SP!, {R0} |
| |
| ; Set R0 to point to the task stack pointer. |
| STMDB SP,{SP}^ |
| SUB SP, SP, #4 |
| LDMIA SP!,{R0} |
| |
| ; Push the return address onto the stack. |
| STMDB R0!, {LR} |
| |
| ; Now LR has been saved, it can be used instead of R0. |
| MOV LR, R0 |
| |
| ; Pop R0 so it can be saved onto the task stack. |
| LDMIA SP!, {R0} |
| |
| ; Push all the system mode registers onto the task stack. |
| STMDB LR,{R0-LR}^ |
| SUB LR, LR, #60 |
| |
| ; Push the SPSR onto the task stack. |
| MRS R0, SPSR |
| STMDB LR!, {R0} |
| |
| .if (__TI_VFP_SUPPORT__) |
| ;Determine if the task maintains an FPU context. |
| LDR R0, ulFPUContextConst |
| LDR R0, [R0] |
| |
| ; Test the flag |
| CMP R0, #0 |
| |
| ; If the task is not using a floating point context then skip the |
| ; saving of the FPU registers. |
| BEQ $+16 |
| FSTMDBD LR!, {D0-D15} |
| FMRX R1, FPSCR |
| STMFD LR!, {R1} |
| |
| ; Save the flag |
| STMDB LR!, {R0} |
| .endif |
| |
| ; Store the new top of stack for the task. |
| LDR R0, pxCurrentTCBConst |
| LDR R0, [R0] |
| STR LR, [R0] |
| |
| .endm |
| |
| ;/*-----------------------------------------------------------*/ |
| ; |
| ; Restore Task Context |
| ; |
| portRESTORE_CONTEXT .macro |
| LDR R0, pxCurrentTCBConst |
| LDR R0, [R0] |
| LDR LR, [R0] |
| |
| .if (__TI_VFP_SUPPORT__) |
| ; The floating point context flag is the first thing on the stack. |
| LDR R0, ulFPUContextConst |
| LDMFD LR!, {R1} |
| STR R1, [R0] |
| |
| ; Test the flag |
| CMP R1, #0 |
| |
| ; If the task is not using a floating point context then skip the |
| ; VFP register loads. |
| BEQ $+16 |
| |
| ; Restore the floating point context. |
| LDMFD LR!, {R0} |
| FLDMIAD LR!, {D0-D15} |
| FMXR FPSCR, R0 |
| .endif |
| |
| ; Get the SPSR from the stack. |
| LDMFD LR!, {R0} |
| MSR SPSR_CSXF, R0 |
| |
| ; Restore all system mode registers for the task. |
| LDMFD LR, {R0-R14}^ |
| |
| ; Restore the return address. |
| LDR LR, [LR, #+60] |
| |
| ; And return - correcting the offset in the LR to obtain the |
| ; correct address. |
| SUBS PC, LR, #4 |
| .endm |
| |
| ;/*-----------------------------------------------------------*/ |
| ; Start the first task by restoring its context. |
| |
| .def vPortStartFirstTask |
| |
| vPortStartFirstTask: |
| portRESTORE_CONTEXT |
| |
| ;/*-----------------------------------------------------------*/ |
| ; Yield to another task. |
| |
| .def vPortYieldProcessor |
| |
| vPortYieldProcessor: |
| ; Within an IRQ ISR the link register has an offset from the true return |
| ; address. SWI doesn't do this. Add the offset manually so the ISR |
| ; return code can be used. |
| ADD LR, LR, #4 |
| |
| ; First save the context of the current task. |
| portSAVE_CONTEXT |
| |
| ; Select the next task to execute. */ |
| BL vTaskSwitchContext |
| |
| ; Restore the context of the task selected to execute. |
| portRESTORE_CONTEXT |
| |
| ;/*-----------------------------------------------------------*/ |
| ; Yield to another task from within the FreeRTOS API |
| |
| .def vPortYeildWithinAPI |
| |
| vPortYeildWithinAPI: |
| ; Save the context of the current task. |
| |
| portSAVE_CONTEXT |
| ; Clear SSI flag. |
| MOVW R0, #0xFFF4 |
| MOVT R0, #0xFFFF |
| LDR R0, [R0] |
| |
| ; Select the next task to execute. */ |
| BL vTaskSwitchContext |
| |
| ; Restore the context of the task selected to execute. |
| portRESTORE_CONTEXT |
| |
| ;/*-----------------------------------------------------------*/ |
| ; Preemptive Tick |
| |
| .def vPortPreemptiveTick |
| |
| vPortPreemptiveTick: |
| |
| ; Save the context of the current task. |
| portSAVE_CONTEXT |
| |
| ; Clear interrupt flag |
| MOVW R0, #0xFC88 |
| MOVT R0, #0xFFFF |
| MOV R1, #1 |
| STR R1, [R0] |
| |
| ; Increment the tick count, making any adjustments to the blocked lists |
| ; that may be necessary. |
| BL xTaskIncrementTick |
| |
| ; Select the next task to execute. |
| CMP R0, #0 |
| BLNE vTaskSwitchContext |
| |
| ; Restore the context of the task selected to execute. |
| portRESTORE_CONTEXT |
| |
| ;------------------------------------------------------------------------------- |
| |
| .if (__TI_VFP_SUPPORT__) |
| |
| .def vPortInitialiseFPSCR |
| |
| vPortInitialiseFPSCR: |
| |
| MOV R0, #0 |
| FMXR FPSCR, R0 |
| BX LR |
| |
| .endif ;__TI_VFP_SUPPORT__ |
| |
| |
| pxCurrentTCBConst .word pxCurrentTCB |
| ulFPUContextConst .word ulTaskHasFPUContext |
| ;------------------------------------------------------------------------------- |