ports/arm9/ac5/src/tx_thread_fiq_nesting_end.s


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;/***************************************************************************
; * Copyright (c) 2024 Microsoft Corporation
; *
; * This program and the accompanying materials are made available under the
; * terms of the MIT License which is available at
; * https://opensource.org/licenses/MIT.
; *
; * SPDX-License-Identifier: MIT
; **************************************************************************/
;
;
;/**************************************************************************/
;/**************************************************************************/
;/**                                                                       */
;/** ThreadX Component                                                     */
;/**                                                                       */
;/**   Thread                                                              */
;/**                                                                       */
;/**************************************************************************/
;/**************************************************************************/
;
;
;#define TX_SOURCE_CODE
;
;
;/* Include necessary system files.  */
;
;#include "tx_api.h"
;#include "tx_thread.h"
;
;
    IF  :DEF:TX_ENABLE_FIQ_SUPPORT
DISABLE_INTS    EQU     0xC0                    ; Disable IRQ & FIQ interrupts
    ELSE
DISABLE_INTS    EQU     0x80                    ; Disable IRQ interrupts
    ENDIF
MODE_MASK       EQU     0x1F                    ; Mode mask
FIQ_MODE_BITS   EQU     0x11                    ; FIQ mode bits
;
;
        AREA ||.text||, CODE, READONLY
;/**************************************************************************/
;/*                                                                        */
;/*  FUNCTION                                               RELEASE        */
;/*                                                                        */
;/*    _tx_thread_fiq_nesting_end                           ARM9/AC5       */
;/*                                                           6.1          */
;/*  AUTHOR                                                                */
;/*                                                                        */
;/*    William E. Lamie, Microsoft Corporation                             */
;/*                                                                        */
;/*  DESCRIPTION                                                           */
;/*                                                                        */
;/*    This function is called by the application from FIQ mode after      */
;/*    _tx_thread_fiq_nesting_start has been called and switches the FIQ   */
;/*    processing from system mode back to FIQ mode prior to the ISR       */
;/*    calling _tx_thread_fiq_context_restore.  Note that this function    */
;/*    assumes the system stack pointer is in the same position after      */
;/*    nesting start function was called.                                  */
;/*                                                                        */
;/*    This function assumes that the system mode stack pointer was setup  */
;/*    during low-level initialization (tx_initialize_low_level.s).        */
;/*                                                                        */
;/*    This function returns with FIQ interrupts disabled.                 */
;/*                                                                        */
;/*  INPUT                                                                 */
;/*                                                                        */
;/*    None                                                                */
;/*                                                                        */
;/*  OUTPUT                                                                */
;/*                                                                        */
;/*    None                                                                */
;/*                                                                        */
;/*  CALLS                                                                 */
;/*                                                                        */
;/*    None                                                                */
;/*                                                                        */
;/*  CALLED BY                                                             */
;/*                                                                        */
;/*    ISRs                                                                */
;/*                                                                        */
;/**************************************************************************/
;VOID   _tx_thread_fiq_nesting_end(VOID)
;{
    EXPORT  _tx_thread_fiq_nesting_end
_tx_thread_fiq_nesting_end
    MOV     r3,lr                               ; Save ISR return address
    MRS     r0, CPSR                            ; Pickup the CPSR
    ORR     r0, r0, #DISABLE_INTS               ; Build disable interrupt value
    MSR     CPSR_cxsf, r0                       ; Disable interrupts
    LDMIA   sp!, {r1, lr}                       ; Pickup saved lr (and r1 throw-away for
                                                ;   8-byte alignment logic)
    BIC     r0, r0, #MODE_MASK                  ; Clear mode bits
    ORR     r0, r0, #FIQ_MODE_BITS              ; Build IRQ mode CPSR
    MSR     CPSR_cxsf, r0                       ; Re-enter IRQ mode
    IF  {INTER} = {TRUE}
    BX      r3                                  ; Return to caller
    ELSE
    MOV     pc, r3                              ; Return to caller
    ENDIF
;}
;
    END