1/***************************************************************************
2 * Copyright (c) 2024 Microsoft Corporation
3 *
4 * This program and the accompanying materials are made available under the
5 * terms of the MIT License which is available at
6 * https://opensource.org/licenses/MIT.
7 *
8 * SPDX-License-Identifier: MIT
9 **************************************************************************/
10
11
12/**************************************************************************/
13/**************************************************************************/
14/**                                                                       */
15/** ThreadX Component                                                     */
16/**                                                                       */
17/**   Thread                                                              */
18/**                                                                       */
19/**************************************************************************/
20/**************************************************************************/
21#ifdef TX_INCLUDE_USER_DEFINE_FILE
22#include "tx_user.h"
23#endif
24
25    .syntax unified
26#if defined(THUMB_MODE)
27    .thumb
28#else
29    .arm
30#endif
31
32    .global     _tx_thread_execute_ptr
33    .global     _tx_thread_current_ptr
34    .global     _tx_timer_time_slice
35
36    .text
37    .align 2
38
39#define IRQ_MODE    0x12            // IRQ mode
40#define SVC_MODE    0x13            // SVC mode
41
42/**************************************************************************/
43/*                                                                        */
44/*  FUNCTION                                               RELEASE        */
45/*                                                                        */
46/*    _tx_thread_schedule                                  ARMv7-A        */
47/*                                                           6.4.0        */
48/*  AUTHOR                                                                */
49/*                                                                        */
50/*    William E. Lamie, Microsoft Corporation                             */
51/*                                                                        */
52/*  DESCRIPTION                                                           */
53/*                                                                        */
54/*    This function waits for a thread control block pointer to appear in */
55/*    the _tx_thread_execute_ptr variable.  Once a thread pointer appears */
56/*    in the variable, the corresponding thread is resumed.               */
57/*                                                                        */
58/*  INPUT                                                                 */
59/*                                                                        */
60/*    None                                                                */
61/*                                                                        */
62/*  OUTPUT                                                                */
63/*                                                                        */
64/*    None                                                                */
65/*                                                                        */
66/*  CALLS                                                                 */
67/*                                                                        */
68/*    None                                                                */
69/*                                                                        */
70/*  CALLED BY                                                             */
71/*                                                                        */
72/*    _tx_initialize_kernel_enter          ThreadX entry function         */
73/*    _tx_thread_system_return             Return to system from thread   */
74/*    _tx_thread_context_restore           Restore thread's context       */
75/*                                                                        */
76/*  RELEASE HISTORY                                                       */
77/*                                                                        */
78/*    DATE              NAME                      DESCRIPTION             */
79/*                                                                        */
80/*  09-30-2020     William E. Lamie         Initial Version 6.1           */
81/*  10-15-2021     William E. Lamie         Modified comment(s), added    */
82/*                                            execution profile support,  */
83/*                                            resulting in version 6.1.9  */
84/*  04-25-2022     Zhen Kong                Updated comments,             */
85/*                                            resulting in version 6.1.11 */
86/*  10-31-2023     Tiejun Zhou              Modified comment(s), added    */
87/*                                            #include tx_user.h,         */
88/*                                            resulting in version 6.3.0  */
89/*  12-31-2023     Yajun Xia                Modified comment(s),          */
90/*                                            Added thumb mode support,   */
91/*                                            resulting in version 6.4.0  */
92/*                                                                        */
93/**************************************************************************/
94#if defined(THUMB_MODE)
95    .thumb_func
96#endif
97    .global _tx_thread_schedule
98    .type  _tx_thread_schedule,function
99_tx_thread_schedule:
100
101    /* Enable interrupts.  */
102
103#ifdef TX_ENABLE_FIQ_SUPPORT
104    CPSIE   if                              // Enable IRQ and FIQ interrupts
105#else
106    CPSIE   i                               // Enable IRQ interrupts
107#endif
108
109    /* Wait for a thread to execute.  */
110    LDR     r1, =_tx_thread_execute_ptr     // Address of thread execute ptr
111
112__tx_thread_schedule_loop:
113
114    LDR     r0, [r1]                        // Pickup next thread to execute
115    CMP     r0, #0                          // Is it NULL?
116    BEQ     __tx_thread_schedule_loop       // If so, keep looking for a thread
117    /* Yes! We have a thread to execute.  Lockout interrupts and
118       transfer control to it.  */
119
120#ifdef TX_ENABLE_FIQ_SUPPORT
121    CPSID   if                              // Disable IRQ and FIQ interrupts
122#else
123    CPSID   i                               // Disable IRQ interrupts
124#endif
125
126    /* Setup the current thread pointer.  */
127
128    LDR     r1, =_tx_thread_current_ptr     // Pickup address of current thread
129    STR     r0, [r1]                        // Setup current thread pointer
130
131    /* Increment the run count for this thread.  */
132
133    LDR     r2, [r0, #4]                    // Pickup run counter
134    LDR     r3, [r0, #24]                   // Pickup time-slice for this thread
135    ADD     r2, r2, #1                      // Increment thread run-counter
136    STR     r2, [r0, #4]                    // Store the new run counter
137
138    /* Setup time-slice, if present.  */
139
140    LDR     r2, =_tx_timer_time_slice       // Pickup address of time-slice variable
141    STR     r3, [r2]                        // Setup time-slice
142
143    LDR     sp, [r0, #8]                    // Switch stack pointers
144
145#if (defined(TX_ENABLE_EXECUTION_CHANGE_NOTIFY) || defined(TX_EXECUTION_PROFILE_ENABLE))
146
147    /* Call the thread entry function to indicate the thread is executing. */
148
149    MOV     r5, r0                          // Save r0
150    BL      _tx_execution_thread_enter      // Call the thread execution enter function
151    MOV     r0, r5                          // Restore r0
152#endif
153
154    /* Determine if an interrupt frame or a synchronous task suspension frame is present. */
155
156    POP     {r4, r5}                        // Pickup the stack type and saved CPSR
157    CMP     r4, #0                          // Check for synchronous context switch
158    BEQ     _tx_solicited_return
159
160#if !defined(THUMB_MODE)
161    MSR     SPSR_cxsf, r5                   // Setup SPSR for return
162#else
163    CPS     #IRQ_MODE                       // Enter IRQ mode
164    MSR     SPSR_cxsf, r5                   // Setup SPSR for return
165    LDR     r1, [r0, #8]                    // Get thread SP
166    LDR     lr, [r1, #0x40]                 // Get thread PC
167    CPS     #SVC_MODE                       // Enter SVC mode
168#endif
169
170#ifdef TX_ENABLE_VFP_SUPPORT
171    LDR     r2, [r0, #144]                  // Pickup the VFP enabled flag
172    CMP     r2, #0                          // Is the VFP enabled?
173    BEQ     _tx_skip_interrupt_vfp_restore  // No, skip VFP interrupt restore
174    VLDMIA  sp!, {D0-D15}                   // Recover D0-D15
175    VLDMIA  sp!, {D16-D31}                  // Recover D16-D31
176    LDR     r4, [sp], #4                    // Pickup FPSCR
177    VMSR    FPSCR, r4                       // Restore FPSCR
178_tx_skip_interrupt_vfp_restore:
179#endif
180
181#if !defined(THUMB_MODE)
182    LDMIA   sp!, {r0-r12, lr, pc}^          // Return to point of thread interrupt
183#else
184    POP     {r0-r12, lr}                    // Restore registers
185    ADD     sp, #4                          // Fix stack pointer (skip PC saved on stack)
186    CPS     #IRQ_MODE                       // Enter IRQ mode
187    SUBS    pc, lr, #0                      // Return to point of thread interrupt
188#endif
189
190_tx_solicited_return:
191
192#ifdef TX_ENABLE_VFP_SUPPORT
193    LDR     r1, [r0, #144]                  // Pickup the VFP enabled flag
194    CMP     r1, #0                          // Is the VFP enabled?
195    BEQ     _tx_skip_solicited_vfp_restore  // No, skip VFP solicited restore
196    VLDMIA  sp!, {D8-D15}                   // Recover D8-D15
197    VLDMIA  sp!, {D16-D31}                  // Recover D16-D31
198    LDR     r4, [sp], #4                    // Pickup FPSCR
199    VMSR    FPSCR, r4                       // Restore FPSCR
200_tx_skip_solicited_vfp_restore:
201#endif
202
203    MSR     CPSR_cxsf, r5                   // Recover CPSR
204    POP     {r4-r11, lr}                    // Restore registers
205    BX      lr                              // Return to caller
206
207#ifdef TX_ENABLE_VFP_SUPPORT
208
209#if defined(THUMB_MODE)
210    .thumb_func
211#endif
212    .global tx_thread_vfp_enable
213    .type  tx_thread_vfp_enable,function
214tx_thread_vfp_enable:
215    MRS     r0, CPSR                            // Pickup current CPSR
216#ifdef TX_ENABLE_FIQ_SUPPORT
217    CPSID   if                                  // Disable IRQ and FIQ
218#else
219    CPSID   i                                   // Disable IRQ
220#endif
221    LDR     r2, =_tx_thread_current_ptr     // Build current thread pointer address
222    LDR     r1, [r2]                        // Pickup current thread pointer
223    CMP     r1, #0                          // Check for NULL thread pointer
224    BEQ     restore_ints                    // If NULL, skip VFP enable
225    MOV     r2, #1                          // Build enable value
226    STR     r2, [r1, #144]                  // Set the VFP enable flag (tx_thread_vfp_enable field in TX_THREAD)
227    B       restore_ints
228
229#if defined(THUMB_MODE)
230    .thumb_func
231#endif
232    .global tx_thread_vfp_disable
233    .type  tx_thread_vfp_disable,function
234tx_thread_vfp_disable:
235    MRS     r0, CPSR                            // Pickup current CPSR
236#ifdef TX_ENABLE_FIQ_SUPPORT
237    CPSID   if                                  // Disable IRQ and FIQ
238#else
239    CPSID   i                                   // Disable IRQ
240#endif
241    LDR     r2, =_tx_thread_current_ptr     // Build current thread pointer address
242    LDR     r1, [r2]                        // Pickup current thread pointer
243    CMP     r1, #0                          // Check for NULL thread pointer
244    BEQ     restore_ints                    // If NULL, skip VFP disable
245    MOV     r2, #0                          // Build disable value
246    STR     r2, [r1, #144]                  // Clear the VFP enable flag (tx_thread_vfp_enable field in TX_THREAD)
247
248restore_ints:
249    TST     r0, #IRQ_MASK
250    BNE     no_irq
251    CPSIE   i
252no_irq:
253#ifdef TX_ENABLE_FIQ_SUPPORT
254    TST     r0, #FIQ_MASK
255    BNE     no_fiq
256    CPSIE   f
257no_fiq:
258#endif
259    BX      lr
260
261#endif
262