rtt-f030/libcpu/arm/stm32/context_iar.S

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;/*
; * File : context.S
; * This file is part of RT-Thread RTOS
; * COPYRIGHT (C) 2006, RT-Thread Development Team
; *
; * The license and distribution terms for this file may be
; * found in the file LICENSE in this distribution or at
; * http://www.rt-thread.org/license/LICENSE
; *
; * Change Logs:
; * Date Author Notes
; * 2009-01-17 Bernard first version
; * 2009-09-27 Bernard add protect when contex switch occurs
; */
;/**
; * @addtogroup STM32
; */
;/*@{*/
NVIC_INT_CTRL EQU 0xE000ED04 ; interrupt control state register
NVIC_SYSPRI2 EQU 0xE000ED20 ; system priority register (2)
NVIC_PENDSV_PRI EQU 0x00FF0000 ; PendSV priority value (lowest)
NVIC_PENDSVSET EQU 0x10000000 ; value to trigger PendSV exception
SECTION .text:CODE(2)
THUMB
REQUIRE8
PRESERVE8
IMPORT rt_thread_switch_interrput_flag
IMPORT rt_interrupt_from_thread
IMPORT rt_interrupt_to_thread
;/*
; * rt_base_t rt_hw_interrupt_disable();
; */
EXPORT rt_hw_interrupt_disable
rt_hw_interrupt_disable:
MRS r0, PRIMASK
CPSID I
BX LR
;/*
; * void rt_hw_interrupt_enable(rt_base_t level);
; */
EXPORT rt_hw_interrupt_enable
rt_hw_interrupt_enable:
MSR PRIMASK, r0
BX LR
;/*
; * void rt_hw_context_switch(rt_uint32 from, rt_uint32 to);
; * r0 --> from
; * r1 --> to
; */
EXPORT rt_hw_context_switch_interrupt
EXPORT rt_hw_context_switch
rt_hw_context_switch_interrupt:
rt_hw_context_switch:
; set rt_thread_switch_interrput_flag to 1
LDR r2, =rt_thread_switch_interrput_flag
LDR r3, [r2]
CMP r3, #1
BEQ _reswitch
MOV 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 --> swith from thread stack
; r1 --> swith to thread stack
; psr, pc, lr, r12, r3, r2, r1, r0 are pushed into [from] stack
EXPORT rt_hw_pend_sv
rt_hw_pend_sv:
; disable interrupt to protect context switch
MRS r2, PRIMASK
CPSID I
; get rt_thread_switch_interrupt_flag
LDR r0, =rt_thread_switch_interrput_flag
LDR r1, [r0]
CBZ r1, pendsv_exit ; pendsv already handled
; clear rt_thread_switch_interrput_flag to 0
MOV r1, #0x00
STR r1, [r0]
LDR r0, =rt_interrupt_from_thread
LDR r1, [r0]
CBZ r1, swtich_to_thread ; skip register save at the first time
MRS r1, psp ; get from thread stack pointer
STMFD r1!, {r4 - r11} ; push r4 - r11 register
LDR r0, [r0]
STR r1, [r0] ; update from thread stack pointer
swtich_to_thread
LDR r1, =rt_interrupt_to_thread
LDR r1, [r1]
LDR r1, [r1] ; load thread stack pointer
LDMFD r1!, {r4 - r11} ; pop r4 - r11 register
MSR psp, r1 ; update stack pointer
pendsv_exit
; restore interrupt
MSR PRIMASK, r2
ORR lr, lr, #0x04
BX lr
;/*
; * void rt_hw_context_switch_to(rt_uint32 to);
; * r0 --> to
; */
EXPORT rt_hw_context_switch_to
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
MOV r0, #0x0
STR r0, [r1]
; set interrupt flag to 1
LDR r1, =rt_thread_switch_interrput_flag
MOV r0, #1
STR r0, [r1]
; set the PendSV exception priority
LDR r0, =NVIC_SYSPRI2
LDR r1, =NVIC_PENDSV_PRI
STR r1, [r0]
LDR r0, =NVIC_INT_CTRL ; trigger the PendSV exception (causes context switch)
LDR r1, =NVIC_PENDSVSET
STR r1, [r0]
CPSIE I ; enable interrupts at processor level
; never reach here!
; compatible with old version
EXPORT rt_hw_interrupt_thread_switch
rt_hw_interrupt_thread_switch:
BX lr
END