144 lines
4.8 KiB
ArmAsm
144 lines
4.8 KiB
ArmAsm
/*
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* Copyright (c) 2013-2018 Arm Limited. All rights reserved.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the License); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an AS IS BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* -----------------------------------------------------------------------------
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*
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* Project: CMSIS-RTOS RTX
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* Title: Cortex-M3 Exception handlers
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*
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* -----------------------------------------------------------------------------
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*/
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.file "irq_cm3.S"
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.syntax unified
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.equ I_T_RUN_OFS, 20 // osRtxInfo.thread.run offset
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.equ TCB_SP_OFS, 56 // TCB.SP offset
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.section ".rodata"
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.global irqRtxLib // Non weak library reference
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irqRtxLib:
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.byte 0
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.thumb
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.section ".text"
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.align 2
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.thumb_func
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.type SVC_Handler, %function
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.global SVC_Handler
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.fnstart
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.cantunwind
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SVC_Handler:
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TST LR,#0x04 // Determine return stack from EXC_RETURN bit 2
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ITE EQ
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MRSEQ R0,MSP // Get MSP if return stack is MSP
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MRSNE R0,PSP // Get PSP if return stack is PSP
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LDR R1,[R0,#24] // Load saved PC from stack
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LDRB R1,[R1,#-2] // Load SVC number
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CBNZ R1,SVC_User // Branch if not SVC 0
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PUSH {R0,LR} // Save SP and EXC_RETURN
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LDM R0,{R0-R3,R12} // Load function parameters and address from stack
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BLX R12 // Call service function
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POP {R12,LR} // Restore SP and EXC_RETURN
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STM R12,{R0-R1} // Store function return values
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SVC_Context:
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LDR R3,=osRtxInfo+I_T_RUN_OFS // Load address of osRtxInfo.run
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LDM R3,{R1,R2} // Load osRtxInfo.thread.run: curr & next
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CMP R1,R2 // Check if thread switch is required
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IT EQ
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BXEQ LR // Exit when threads are the same
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CBZ R1,SVC_ContextSwitch // Branch if running thread is deleted
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SVC_ContextSave:
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STMDB R12!,{R4-R11} // Save R4..R11
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STR R12,[R1,#TCB_SP_OFS] // Store SP
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SVC_ContextSwitch:
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STR R2,[R3] // osRtxInfo.thread.run: curr = next
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SVC_ContextRestore:
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LDR R0,[R2,#TCB_SP_OFS] // Load SP
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LDMIA R0!,{R4-R11} // Restore R4..R11
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MSR PSP,R0 // Set PSP
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MVN LR,#~0xFFFFFFFD // Set EXC_RETURN value
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SVC_Exit:
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BX LR // Exit from handler
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SVC_User:
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LDR R2,=osRtxUserSVC // Load address of SVC table
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LDR R3,[R2] // Load SVC maximum number
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CMP R1,R3 // Check SVC number range
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BHI SVC_Exit // Branch if out of range
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PUSH {R0,LR} // Save SP and EXC_RETURN
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LDR R12,[R2,R1,LSL #2] // Load address of SVC function
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LDM R0,{R0-R3} // Load function parameters from stack
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BLX R12 // Call service function
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POP {R12,LR} // Restore SP and EXC_RETURN
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STR R0,[R12] // Store function return value
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BX LR // Return from handler
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.fnend
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.size SVC_Handler, .-SVC_Handler
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.thumb_func
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.type PendSV_Handler, %function
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.global PendSV_Handler
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.fnstart
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.cantunwind
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PendSV_Handler:
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PUSH {R0,LR} // Save EXC_RETURN
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BL osRtxPendSV_Handler // Call osRtxPendSV_Handler
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POP {R0,LR} // Restore EXC_RETURN
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MRS R12,PSP
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B SVC_Context
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.fnend
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.size PendSV_Handler, .-PendSV_Handler
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.thumb_func
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.type SysTick_Handler, %function
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.global SysTick_Handler
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.fnstart
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.cantunwind
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SysTick_Handler:
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PUSH {R0,LR} // Save EXC_RETURN
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BL osRtxTick_Handler // Call osRtxTick_Handler
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POP {R0,LR} // Restore EXC_RETURN
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MRS R12,PSP
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B SVC_Context
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.fnend
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.size SysTick_Handler, .-SysTick_Handler
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.end
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