/*
 * Copyright (c) 2006-2022, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2006-03-13     Bernard      first version
 */

#define NOINT           0xc0

/*
 * rt_base_t rt_hw_interrupt_disable()/*
 */
.globl rt_hw_interrupt_disable
rt_hw_interrupt_disable:
    mrs r0, cpsr
    orr r1, r0, #NOINT
    msr cpsr_c, r1
    mov pc, lr

/*
 * void rt_hw_interrupt_enable(rt_base_t level)/*
 */
.globl rt_hw_interrupt_enable
rt_hw_interrupt_enable:
    msr cpsr, r0
    mov pc, lr

/*
 * void rt_hw_context_switch(rt_uint32 from, rt_uint32 to)/*
 * r0 --> from
 * r1 --> to
 */
.globl rt_hw_context_switch
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 */

/*
 * void rt_hw_context_switch_to(rt_uint32 to)/*
 * r0 --> to
 */
.globl rt_hw_context_switch_to
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 */

/*
 * void rt_hw_context_switch_interrupt(rt_uint32 from, rt_uint32 to)/*
 */
.globl rt_thread_switch_interrupt_flag
.globl rt_interrupt_from_thread
.globl rt_interrupt_to_thread
.globl rt_hw_context_switch_interrupt
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]
    mov     pc, lr