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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.
* 2013-02-20 aozima port to gcc.
* 2013-06-18 aozima add restore MSP feature.
* 2013-11-04 bright fixed hardfault bug for gcc.
* 2019-03-31 xuzhuoyi port to Cortex-M23.
*/
.cpu cortex-m23
.fpu softvfp
.syntax unified
.thumb
.text
.equ SCB_VTOR, 0xE000ED08 /* Vector Table Offset Register */
.equ NVIC_INT_CTRL, 0xE000ED04 /* interrupt control state register */
.equ NVIC_SHPR3, 0xE000ED20 /* system priority register (3) */
.equ NVIC_PENDSV_PRI, 0xFFFF0000 /* PendSV and SysTick priority value (lowest) */
.equ NVIC_PENDSVSET, 0x10000000 /* value to trigger PendSV exception */
/*
* rt_base_t rt_hw_interrupt_disable();
*/
.global rt_hw_interrupt_disable
.type rt_hw_interrupt_disable, %function
rt_hw_interrupt_disable:
MRS R0, PRIMASK
CPSID I
BX LR
/*
* void rt_hw_interrupt_enable(rt_base_t level);
*/
.global rt_hw_interrupt_enable
.type rt_hw_interrupt_enable, %function
rt_hw_interrupt_enable:
MSR PRIMASK, R0
BX LR
/*
* void rt_hw_context_switch(rt_uint32 from, rt_uint32 to);
* R0 --> from
* R1 --> to
*/
.global rt_hw_context_switch_interrupt
.type rt_hw_context_switch_interrupt, %function
.global rt_hw_context_switch
.type rt_hw_context_switch, %function
rt_hw_context_switch_interrupt:
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, #1
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
/* R0 --> switch from thread stack
* R1 --> switch to thread stack
* psr, pc, LR, R12, R3, R2, R1, R0 are pushed into [from] stack
*/
.global PendSV_Handler
.type PendSV_Handler, %function
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, #0
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
/*
* void rt_hw_context_switch_to(rt_uint32 to);
* R0 --> to
*/
.global rt_hw_context_switch_to
.type rt_hw_context_switch_to, %function
rt_hw_context_switch_to:
LDR R1, =rt_interrupt_to_thread
STR R0, [R1]
/* set from thread to 0 */
LDR R1, =rt_interrupt_from_thread
MOVS R0, #0
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 */
LDR R0, =NVIC_INT_CTRL /* trigger the PendSV exception (causes context switch) */
LDR R1, =NVIC_PENDSVSET
STR R1, [R0]
NOP
/* restore MSP */
LDR R0, =SCB_VTOR
LDR R0, [R0]
LDR R0, [R0]
NOP
MSR MSP, R0
/* enable interrupts at processor level */
CPSIE I
/* ensure PendSV exception taken place before subsequent operation */
DSB
ISB
/* never reach here! */
/* compatible with old version */
.global rt_hw_interrupt_thread_switch
.type rt_hw_interrupt_thread_switch, %function
rt_hw_interrupt_thread_switch:
BX LR
NOP
.global HardFault_Handler
.type HardFault_Handler, %function
HardFault_Handler:
/* get current context */
MRS R0, PSP /* get fault thread stack pointer */
PUSH {LR}
BL rt_hw_hard_fault_exception
POP {PC}
/*
* rt_uint32_t rt_hw_interrupt_check(void);
* R0 --> state
*/
.global rt_hw_interrupt_check
.type rt_hw_interrupt_check, %function
rt_hw_interrupt_check:
MRS R0, IPSR
BX LR
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