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;/*
; * File : context_rvds.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
; * 2009-01-20 Bernard first version
; * 2011-07-22 Bernard added thumb mode porting
; */
Mode_USR EQU 0x10
Mode_FIQ EQU 0x11
Mode_IRQ EQU 0x12
Mode_SVC EQU 0x13
Mode_ABT EQU 0x17
Mode_UND EQU 0x1B
Mode_SYS EQU 0x1F
I_Bit EQU 0x80 ; when I bit is set, IRQ is disabled
F_Bit EQU 0x40 ; when F bit is set, FIQ is disabled
NOINT EQU 0xc0 ; disable interrupt in psr
AREA |.text|, CODE, READONLY, ALIGN=2
ARM
REQUIRE8
PRESERVE8
;/*
; * rt_base_t rt_hw_interrupt_disable();
; */
rt_hw_interrupt_disable PROC
EXPORT rt_hw_interrupt_disable
MRS r0, cpsr
ORR r1, r0, #NOINT
MSR cpsr_c, r1
BX lr
ENDP
;/*
; * void rt_hw_interrupt_enable(rt_base_t level);
; */
rt_hw_interrupt_enable PROC
EXPORT rt_hw_interrupt_enable
MSR cpsr_c, r0
BX lr
ENDP
;/*
; * void rt_hw_context_switch(rt_uint32 from, rt_uint32 to);
; * r0 --> from
; * r1 --> to
; */
rt_hw_context_switch PROC
EXPORT rt_hw_context_switch
STMFD sp!, {lr} ; push pc (lr should be pushed in place of PC)
STMFD sp!, {r0-r12, lr} ; push lr & register file
MRS r4, cpsr
TST lr, #0x01
BEQ _ARM_MODE
ORR r4, r4, #0x20 ; it's thumb code
_ARM_MODE
STMFD sp!, {r4} ; push cpsr
STR sp, [r0] ; store sp in preempted tasks TCB
LDR sp, [r1] ; get new task stack pointer
LDMFD sp!, {r4} ; pop new task cpsr to spsr
MSR spsr_cxsf, r4
BIC r4, r4, #0x20 ; must be ARM mode
MSR cpsr_cxsf, r4
LDMFD sp!, {r0-r12, lr, pc}^ ; pop new task r0-r12, lr & pc, copy spsr to cpsr
ENDP
;/*
; * void rt_hw_context_switch_to(rt_uint32 to);
; * r0 --> to
; */
rt_hw_context_switch_to PROC
EXPORT rt_hw_context_switch_to
LDR sp, [r0] ; get new task stack pointer
LDMFD sp!, {r4} ; pop new task cpsr to spsr
MSR spsr_cxsf, r4
BIC r4, r4, #0x20 ; must be ARM mode
MSR cpsr_cxsf, r4
LDMFD sp!, {r0-r12, lr, pc}^ ; pop new task r0-r12, lr & pc, copy spsr to cpsr
ENDP
;/*
; * void rt_hw_context_switch_interrupt(rt_uint32 from, rt_uint32 to);
; */
IMPORT rt_thread_switch_interrupt_flag
IMPORT rt_interrupt_from_thread
IMPORT rt_interrupt_to_thread
rt_hw_context_switch_interrupt PROC
EXPORT rt_hw_context_switch_interrupt
LDR r2, =rt_thread_switch_interrupt_flag
LDR r3, [r2]
CMP r3, #1
BEQ _reswitch
MOV r3, #1 ; set rt_thread_switch_interrupt_flag to 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]
BX lr
ENDP
; /*
; * void rt_hw_context_switch_interrupt_do(rt_base_t flag)
; */
rt_hw_context_switch_interrupt_do PROC
EXPORT rt_hw_context_switch_interrupt_do
MOV r1, #0 ; clear flag
STR r1, [r0]
LDMFD sp!, {r0-r12,lr}; reload saved registers
STMFD sp!, {r0-r3} ; save r0-r3
MOV r1, sp
ADD sp, sp, #16 ; restore sp
SUB r2, lr, #4 ; save old task's pc to r2
MRS r3, spsr ; get cpsr of interrupt thread
; switch to SVC mode and no interrupt
MSR cpsr_c, #I_Bit:OR:F_Bit:OR:Mode_SVC
STMFD sp!, {r2} ; push old task's pc
STMFD sp!, {r4-r12,lr}; push old task's lr,r12-r4
MOV r4, r1 ; Special optimised code below
MOV r5, r3
LDMFD r4!, {r0-r3}
STMFD sp!, {r0-r3} ; push old task's r3-r0
STMFD sp!, {r5} ; push old task's cpsr
LDR r4, =rt_interrupt_from_thread
LDR r5, [r4]
STR sp, [r5] ; store sp in preempted tasks's TCB
LDR r6, =rt_interrupt_to_thread
LDR r6, [r6]
LDR sp, [r6] ; get new task's stack pointer
LDMFD sp!, {r4} ; pop new task's cpsr to spsr
MSR spsr_cxsf, r4
BIC r4, r4, #0x20 ; must be ARM mode
MSR cpsr_cxsf, r4
LDMFD sp!, {r0-r12,lr,pc}^ ; pop new task's r0-r12,lr & pc, copy spsr to cpsr
ENDP
END
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