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#include "nds32.h"
#include "os_cpu_common.h"
#include "config.h"
.align 4
! void rt_hw_context_switch(rt_uint32 from, rt_uint32 to);
! R0 --> from
! R1 --> to
.section .text
.global rt_hw_context_switch_interrupt
.global rt_hw_context_switch
rt_hw_context_switch_interrupt:
rt_hw_context_switch:
push25 $r6,#8 ! {$r6, $fp, $gp, $lp}
la $r2, rt_thread_switch_interrupt_flag
lw $r3, [$r2]
movi $r4, #1
beq $r3, $r4, _reswitch
sw $r4, [$r2] ! set rt_thread_switch_interrupt_flag to 1
la $r2, rt_interrupt_from_thread
sw $r0, [$r2] ! set rt_interrupt_from_thread
_reswitch:
la $r2, rt_interrupt_to_thread
sw $r1, [$r2] ! set rt_interrupt_to_thread
bal hal_intc_swi_trigger ! trigger the swi exception (causes context switch)
pop25 $r6,#8 ! {$r6, $fp, $gp, $lp}
! R0 --> switch from thread stack
! R1 --> switch to thread stack
! psr, pc, LR, R12, R3, R2, R1, R0 are pushed into [from] stack
.align 4
.global OS_Trap_Interrupt_SWI
OS_Trap_Interrupt_SWI:
! pushm $r0, $r5
setgie.d ! disable interrupt to protect context switch
dsb
IntlDescend ! Descend interrupt level
movi $r0, 0x0
mtsr $r0, $INT_PEND ! clean SWI pending
la $r0, rt_thread_switch_interrupt_flag ! get rt_thread_switch_interrupt_flag
lw $r1, [$r0]
beqz $r1, pendsv_exit ! swi has already been handled
movi $r1, #0
sw $r1, [$r0] ! clear rt_thread_switch_interrupt_flag to 0
la $r0, rt_interrupt_from_thread
lw $r1, [$r0]
beqz $r1, switch_to_thread ! skip register save at the first time(os startup phase)
SAVE_ALL
move $r1, $sp
la $r0, rt_interrupt_from_thread
lw $r0, [$r0]
sw $r1, [$r0]
switch_to_thread:
la $r1, rt_interrupt_to_thread
lw $r1, [$r1]
lw $r1, [$r1] ! load thread stack pointer
move $sp, $r1 ! update stack pointer
RESTORE_ALL ! pop registers
pendsv_exit:
setgie.e
iret
.align 4
! void rt_hw_context_switch_to(rt_uint32 to);
! R0 --> to
.global rt_hw_context_switch_to
rt_hw_context_switch_to:
la $r1, rt_interrupt_to_thread
sw $r0, [$r1]
! set from thread to 0
la $r1, rt_interrupt_from_thread
movi $r0, #0
sw $r0, [$r1]
! set interrupt flag to 1
la $r1, rt_thread_switch_interrupt_flag
movi $r0, #1
sw $r0, [$r1]
! set the SWI exception priority(must be the lowest level)
! todo
! trigger the SWI exception (causes context switch)
jal hal_intc_swi_trigger
setgie.e ! enable interrupts at processor level
1:
b 1b ! never reach here
#ifndef VECTOR_NUMINTRS
#define VECTOR_NUMINTRS 32
#endif
.global OS_Trap_Int_Common
! Set up Interrupt vector ISR
! HW#IRQ_SWI_VECTOR : OS_Trap_Interrupt_SWI (SWI)
! HW#n : OS_Trap_Int_Common
.macro SET_HWISR num
.global OS_Trap_Interrupt_HW\num
.if \num == IRQ_SWI_VECTOR
.set OS_Trap_Interrupt_HW\num, OS_Trap_Interrupt_SWI
.else
.set OS_Trap_Interrupt_HW\num, OS_Trap_Int_Common
.endif
.endm
.altmacro
.set irqno, 0
.rept VECTOR_NUMINTRS
SET_HWISR %irqno
.set irqno, irqno+1
.endr
.noaltmacro
! .global OS_Trap_Int_Common
OS_Trap_Int_Common:
#ifdef MPU_SUPPORT
mfsr $p1, $PSW
ori $p1, $p1, (PSW_mskIT | PSW_mskDT)
mtsr $p1, $PSW ! enable IT/DT
dsb
pushm $r0, $r5
move $r0, $p0 ! IRQ number
#endif
! $r0 : HW Interrupt vector number
SAVE_CALLER
IntlDescend ! Descend interrupt level
mfsr $r1, $IPSW ! Use IPSW.CPL to check come from thread or ISR
srli45 $r1, #PSW_offCPL
fexti33 $r1, #0x2 ! IPSW.CPL
bnec $r1, #0x7, 2f ! IPSW.CPL != 7, come form ISR, reentrant
move $fp, $sp ! save old stack pointer
la $sp, __OS_Int_Stack ! switch to interrupt stack
2:
setgie.e ! allow nested now
! The entire CPU state is now stashed on the stack,
! and the stack is also 8-byte alignment.
! We can call C program based interrupt handler now.
la $r1, OS_CPU_Vector_Table
lw $r1, [$r1+($r0<<2)] ! ISR function pointer
jral $r1 ! Call ISR
la $r1, __OS_Int_Stack ! Check for nested interruption return
bne $r1, $sp, 3f ! $sp != __OS_Int_Stack?
move $sp, $fp ! Move back to the thread stack
3:
RESTORE_CALLER
iret
! .set OS_Trap_Interrupt_HW9, OS_Trap_Interrupt_SWI
! .set OS_Trap_Interrupt_HW19, OS_Trap_Int_Common
!*********************************************
! POINTERS TO VARIABLES
!*********************************************
#ifdef MPU_SUPPORT
.section privileged_data
#else
.section .bss
#endif
.skip IRQ_STACK_SIZE
.align 3
__OS_Int_Stack:
.end
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