1@/**************************************************************************/
2@/*                                                                        */
3@/*       Copyright (c) Microsoft Corporation. All rights reserved.        */
4@/*                                                                        */
5@/*       This software is licensed under the Microsoft Software License   */
6@/*       Terms for Microsoft Azure RTOS. Full text of the license can be  */
7@/*       found in the LICENSE file at https://aka.ms/AzureRTOS_EULA       */
8@/*       and in the root directory of this software.                      */
9@/*                                                                        */
10@/**************************************************************************/
11@
12@
13@/**************************************************************************/
14@/**************************************************************************/
15@/**                                                                       */
16@/** ThreadX Component                                                     */
17@/**                                                                       */
18@/**   Thread                                                              */
19@/**                                                                       */
20@/**************************************************************************/
21@/**************************************************************************/
22#ifdef TX_INCLUDE_USER_DEFINE_FILE
23#include "tx_user.h"
24#endif
25
26IRQ_DISABLE     =       0x80                    @ IRQ disable bit
27MODE_MASK       =       0x1F                    @ Mode mask
28SYS_MODE_BITS   =       0x1F                    @ System mode bits
29@
30@
31@/* No 16-bit Thumb mode veneer code is needed for _tx_thread_irq_nesting_start
32@   since it will never be called 16-bit mode.  */
33@
34    .arm
35    .text
36    .align 2
37@/**************************************************************************/
38@/*                                                                        */
39@/*  FUNCTION                                               RELEASE        */
40@/*                                                                        */
41@/*    _tx_thread_irq_nesting_start                         ARM9/GNU       */
42@/*                                                           6.2.1        */
43@/*  AUTHOR                                                                */
44@/*                                                                        */
45@/*    William E. Lamie, Microsoft Corporation                             */
46@/*                                                                        */
47@/*  DESCRIPTION                                                           */
48@/*                                                                        */
49@/*    This function is called by the application from IRQ mode after      */
50@/*    _tx_thread_context_save has been called and switches the IRQ        */
51@/*    processing to the system mode so nested IRQ interrupt processing    */
52@/*    is possible (system mode has its own "lr" register).  Note that     */
53@/*    this function assumes that the system mode stack pointer was setup  */
54@/*    during low-level initialization (tx_initialize_low_level.s).        */
55@/*                                                                        */
56@/*    This function returns with IRQ interrupts enabled.                  */
57@/*                                                                        */
58@/*  INPUT                                                                 */
59@/*                                                                        */
60@/*    None                                                                */
61@/*                                                                        */
62@/*  OUTPUT                                                                */
63@/*                                                                        */
64@/*    None                                                                */
65@/*                                                                        */
66@/*  CALLS                                                                 */
67@/*                                                                        */
68@/*    None                                                                */
69@/*                                                                        */
70@/*  CALLED BY                                                             */
71@/*                                                                        */
72@/*    ISRs                                                                */
73@/*                                                                        */
74@/*  RELEASE HISTORY                                                       */
75@/*                                                                        */
76@/*    DATE              NAME                      DESCRIPTION             */
77@/*                                                                        */
78@/*  09-30-2020     William E. Lamie         Initial Version 6.1           */
79@/*  03-08-2023     Cindy Deng               Modified comment(s), added    */
80@/*                                            #include tx_user.h,         */
81@/*                                            resulting in version 6.2.1  */
82@/*                                                                        */
83@/**************************************************************************/
84@VOID   _tx_thread_irq_nesting_start(VOID)
85@{
86    .global  _tx_thread_irq_nesting_start
87    .type    _tx_thread_irq_nesting_start,function
88_tx_thread_irq_nesting_start:
89    MOV     r3,lr                               @ Save ISR return address
90    MRS     r0, CPSR                            @ Pickup the CPSR
91    BIC     r0, r0, #MODE_MASK                  @ Clear the mode bits
92    ORR     r0, r0, #SYS_MODE_BITS              @ Build system mode CPSR
93    MSR     CPSR_cxsf, r0                       @ Enter system mode
94    STMDB   sp!, {r1, lr}                       @ Push the system mode lr on the system mode stack
95                                                @   and push r1 just to keep 8-byte alignment
96    BIC     r0, r0, #IRQ_DISABLE                @ Build enable IRQ CPSR
97    MSR     CPSR_cxsf, r0                       @ Enter system mode
98    MOV     pc, r3                              @ Return to caller
99@}
100
101