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|
;/*
; * Copyright (c) 2006-2022, RT-Thread Development Team
; *
; * SPDX-License-Identifier: Apache-2.0
; *
; * Change Logs:
; * Date Author Notes
; * 2010-01-25 Bernard first version
; * 2012-06-01 aozima set pendsv priority to 0xFF.
; * 2012-08-17 aozima fixed bug: store r8 - r11.
; * 2013-06-18 aozima add restore MSP feature.
; * 2019-03-31 xuzhuoyi port to Cortex-M23.
; */
;/**
; * @addtogroup CORTEX-M23
; */
;/*@{*/
SCB_VTOR EQU 0xE000ED08 ; Vector Table Offset Register
NVIC_INT_CTRL EQU 0xE000ED04 ; interrupt control state register
NVIC_SHPR3 EQU 0xE000ED20 ; system priority register (2)
NVIC_PENDSV_PRI EQU 0xFFFF0000 ; PendSV and SysTick priority value (lowest)
NVIC_PENDSVSET EQU 0x10000000 ; value to trigger PendSV exception
AREA |.text|, CODE, READONLY, ALIGN=2
THUMB
REQUIRE8
PRESERVE8
IMPORT rt_thread_switch_interrupt_flag
IMPORT rt_interrupt_from_thread
IMPORT rt_interrupt_to_thread
;/*
; * rt_base_t rt_hw_interrupt_disable();
; */
rt_hw_interrupt_disable PROC
EXPORT rt_hw_interrupt_disable
MRS r0, PRIMASK
CPSID I
BX LR
ENDP
;/*
; * void rt_hw_interrupt_enable(rt_base_t level);
; */
rt_hw_interrupt_enable PROC
EXPORT rt_hw_interrupt_enable
MSR PRIMASK, r0
BX LR
ENDP
;/*
; * void rt_hw_context_switch(rt_uint32 from, rt_uint32 to);
; * r0 --> from
; * r1 --> to
; */
rt_hw_context_switch_interrupt
EXPORT rt_hw_context_switch_interrupt
rt_hw_context_switch PROC
EXPORT rt_hw_context_switch
; set rt_thread_switch_interrupt_flag to 1
LDR r2, =rt_thread_switch_interrupt_flag
LDR r3, [r2]
CMP r3, #1
BEQ _reswitch
MOVS r3, #0x01
STR r3, [r2]
LDR r2, =rt_interrupt_from_thread ; set rt_interrupt_from_thread
STR r0, [r2]
_reswitch
LDR r2, =rt_interrupt_to_thread ; set rt_interrupt_to_thread
STR r1, [r2]
LDR r0, =NVIC_INT_CTRL ; trigger the PendSV exception (causes context switch)
LDR r1, =NVIC_PENDSVSET
STR r1, [r0]
BX LR
ENDP
; r0 --> switch from thread stack
; r1 --> switch to thread stack
; psr, pc, lr, r12, r3, r2, r1, r0 are pushed into [from] stack
PendSV_Handler PROC
EXPORT PendSV_Handler
; disable interrupt to protect context switch
MRS r2, PRIMASK
CPSID I
; get rt_thread_switch_interrupt_flag
LDR r0, =rt_thread_switch_interrupt_flag
LDR r1, [r0]
CMP r1, #0x00
BEQ pendsv_exit ; pendsv already handled
; clear rt_thread_switch_interrupt_flag to 0
MOVS r1, #0x00
STR r1, [r0]
LDR r0, =rt_interrupt_from_thread
LDR r1, [r0]
CMP r1, #0x00
BEQ switch_to_thread ; skip register save at the first time
MRS r1, psp ; get from thread stack pointer
SUBS r1, r1, #0x20 ; space for {r4 - r7} and {r8 - r11}
LDR r0, [r0]
STR r1, [r0] ; update from thread stack pointer
STMIA r1!, {r4 - r7} ; push thread {r4 - r7} register to thread stack
MOV r4, r8 ; mov thread {r8 - r11} to {r4 - r7}
MOV r5, r9
MOV r6, r10
MOV r7, r11
STMIA r1!, {r4 - r7} ; push thread {r8 - r11} high register to thread stack
switch_to_thread
LDR r1, =rt_interrupt_to_thread
LDR r1, [r1]
LDR r1, [r1] ; load thread stack pointer
LDMIA r1!, {r4 - r7} ; pop thread {r4 - r7} register from thread stack
PUSH {r4 - r7} ; push {r4 - r7} to MSP for copy {r8 - r11}
LDMIA r1!, {r4 - r7} ; pop thread {r8 - r11} high register from thread stack to {r4 - r7}
MOV r8, r4 ; mov {r4 - r7} to {r8 - r11}
MOV r9, r5
MOV r10, r6
MOV r11, r7
POP {r4 - r7} ; pop {r4 - r7} from MSP
MSR psp, r1 ; update stack pointer
pendsv_exit
; restore interrupt
MSR PRIMASK, r2
MOVS r0, #0x03
RSBS r0, r0, #0x00
BX r0
ENDP
;/*
; * void rt_hw_context_switch_to(rt_uint32 to);
; * r0 --> to
; * this fucntion is used to perform the first thread switch
; */
rt_hw_context_switch_to PROC
EXPORT rt_hw_context_switch_to
; set to thread
LDR r1, =rt_interrupt_to_thread
STR r0, [r1]
; set from thread to 0
LDR r1, =rt_interrupt_from_thread
MOVS r0, #0x0
STR r0, [r1]
; set interrupt flag to 1
LDR r1, =rt_thread_switch_interrupt_flag
MOVS r0, #1
STR r0, [r1]
; set the PendSV and SysTick exception priority
LDR r0, =NVIC_SHPR3
LDR r1, =NVIC_PENDSV_PRI
LDR r2, [r0,#0x00] ; read
ORRS r1,r1,r2 ; modify
STR r1, [r0] ; write-back
; trigger the PendSV exception (causes context switch)
LDR r0, =NVIC_INT_CTRL
LDR r1, =NVIC_PENDSVSET
STR r1, [r0]
; restore MSP
LDR r0, =SCB_VTOR
LDR r0, [r0]
LDR r0, [r0]
MSR msp, r0
; enable interrupts at processor level
CPSIE I
; ensure PendSV exception taken place before subsequent operation
DSB
ISB
; never reach here!
ENDP
; compatible with old version
rt_hw_interrupt_thread_switch PROC
EXPORT rt_hw_interrupt_thread_switch
BX lr
ENDP
IMPORT rt_hw_hard_fault_exception
HardFault_Handler PROC
EXPORT HardFault_Handler
; get current context
MRS r0, psp ; get fault thread stack pointer
PUSH {lr}
BL rt_hw_hard_fault_exception
POP {pc}
ENDP
ALIGN 4
END
|
