/*
 * Copyright (c) 2006-2018, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2009-01-20     Bernard      first version
 */

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
    STMFD	sp!, {r4}			; push cpsr
    MRS		r4, spsr
    STMFD	sp!, {r4}			; push spsr

    STR	sp, [r0]				; store sp in preempted tasks TCB
    LDR	sp, [r1]				; get new task stack pointer

    LDMFD	sp!, {r4}			; pop new task spsr
    MSR	spsr_cxsf, r4
    LDMFD	sp!, {r4}			; pop new task cpsr
    MSR	cpsr_cxsf, r4

    LDMFD	sp!, {r0-r12, lr, pc}	; pop new task r0-r12, lr & pc
    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 spsr
    MSR	spsr_cxsf, r4
    LDMFD	sp!, {r4}			; pop new task cpsr
    MSR	cpsr_cxsf, r4

    LDMFD	sp!, {r0-r12, lr, pc}	; pop new task r0-r12, lr & pc
    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

    END