;********************************************************************************************************
;                                               uC/CPU
;                                    CPU CONFIGURATION & PORT LAYER
;
;                    Copyright 2004-2021 Silicon Laboratories Inc. www.silabs.com
;
;                                 SPDX-License-Identifier: APACHE-2.0
;
;               This software is subject to an open source license and is distributed by
;                Silicon Laboratories Inc. pursuant to the terms of the Apache License,
;                    Version 2.0 available at www.apache.org/licenses/LICENSE-2.0.
;
;********************************************************************************************************

;********************************************************************************************************
;
;                                            CPU PORT FILE
;
;                                               RISC-V
;                                           GNU C Compiler
;
; Filename : cpu_a.S
; Version  : V1.32.01
;********************************************************************************************************


;********************************************************************************************************
;                                           PUBLIC FUNCTIONS
;********************************************************************************************************

    PUBLIC  CPU_SR_Save
    PUBLIC  CPU_SR_Restore

    PUBLIC  CPU_IntDis
    PUBLIC  CPU_IntEn


;********************************************************************************************************
;                                                EQUATES
;********************************************************************************************************

CPU_MSTATUS_MIE    DEFINE     0x08


;********************************************************************************************************
;                                      CODE GENERATION DIRECTIVES
;********************************************************************************************************


;********************************************************************************************************
;                                      DISABLE/ENABLE INTERRUPTS
;
; Description : Disable/Enable interrupts.
;
;               (1) (a) For CPU_CRITICAL_METHOD_INT_DIS_EN, interrupts are enabled/disabled WITHOUT saving
;                       or restoring the state of the interrupt status.
;
;
; Prototypes  : void  CPU_IntDis(void);
;               void  CPU_IntEn (void);
;********************************************************************************************************

    SECTION `.text`:CODE:REORDER:NOROOT(2)
    CODE
CPU_IntDis:
; Disable global interupt
    li     t0, CPU_MSTATUS_MIE
    csrrc  zero, mstatus, t0
    ret


    SECTION `.text`:CODE:REORDER:NOROOT(2)
    CODE
CPU_IntEn:
; Enable global interupt
    li     t0, CPU_MSTATUS_MIE
    csrrs  zero, mstatus, t0
    ret



;********************************************************************************************************
;                                      CRITICAL SECTION FUNCTIONS
;
; Description : Disable/Enable interrupts by preserving the state of interrupts.  Generally speaking, the
;               state of the interrupt disable flag is stored in the local variable 'cpu_sr' & interrupts
;               are then disabled ('cpu_sr' is allocated in all functions that need to disable interrupts).
;               The previous interrupt state is restored by copying 'cpu_sr' into the CPU's status register.
;
; Prototypes  : CPU_SR  CPU_SR_Save   (void);
;               void    CPU_SR_Restore(CPU_SR  cpu_sr);
;
; Note(s)     : (1) These functions are used in general like this :
;
;                       void  Task (void  *p_arg)
;                       {
;                           CPU_SR_ALLOC();                     /* Allocate storage for CPU status register */
;                               :
;                               :
;                           CPU_CRITICAL_ENTER();               /* cpu_sr = CPU_SR_Save();                  */
;                               :
;                               :
;                           CPU_CRITICAL_EXIT();                /* CPU_SR_Restore(cpu_sr);                  */
;                               :
;                       }
;********************************************************************************************************

    SECTION `.text`:CODE:REORDER:NOROOT(2)
    CODE
CPU_SR_Save:
; Save the Machine status register
    csrr   a0, mstatus
; Disable global interupt
    li     t0, CPU_MSTATUS_MIE
    csrrc  zero, mstatus, t0
    ret

    SECTION `.text`:CODE:REORDER:NOROOT(2)
    CODE
CPU_SR_Restore:
; restore the Machine status register previous state
    csrw   mstatus, a0
    ret


;********************************************************************************************************
;                                     CPU ASSEMBLY PORT FILE END
;********************************************************************************************************