readme_threadx.txt
1 Microsoft's Azure RTOS ThreadX for Cortex-M23
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3 Using the IAR Tools
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61. Building the ThreadX run-time Library
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8Import all ThreadX common and port-specific source files into an IAR project.
9Configure the project to build a library rather than an executable. This
10results in the ThreadX run-time library file tx.a, which is needed by
11the application.
12Files tx_thread_stack_error_handler.c and tx_thread_stack_error_notify.c
13replace the common files of the same name.
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152. Demonstration System
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17No demonstration is provided because the IAR EWARM 8.50 simulator does
18not simulate the Cortex-M23 correctly.
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213. System Initialization
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23The entry point in ThreadX for the Cortex-M23 using IAR tools is at label
24__iar_program_start. This is defined within the IAR compiler's startup code.
25In addition, this is where all static and global preset C variable
26initialization processing takes place.
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28The ThreadX tx_initialize_low_level.s file is responsible for setting up
29various system data structures, and a periodic timer interrupt source.
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31The _tx_initialize_low_level function inside of tx_initialize_low_level.s
32also determines the first available address for use by the application, which
33is supplied as the sole input parameter to your application definition function,
34tx_application_define. To accomplish this, a section is created in
35tx_initialize_low_level.s called FREE_MEM, which must be located after all
36other RAM sections in memory.
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394. Register Usage and Stack Frames
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41The following defines the saved context stack frames for context switches
42that occur as a result of interrupt handling or from thread-level API calls.
43All suspended threads have the same stack frame in the Cortex-M23 version of
44ThreadX. The top of the suspended thread's stack is pointed to by
45tx_thread_stack_ptr in the associated thread control block TX_THREAD.
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47 Stack Offset Stack Contents
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49 0x00 LR Interrupted LR (LR at time of PENDSV)
50 0x04 r8
51 0x08 r9
52 0x0C r10
53 0x10 r11
54 0x14 r4
55 0x18 r5
56 0x1C r6
57 0x20 r7
58 0x24 r0 (Hardware stack starts here!!)
59 0x28 r1
60 0x2C r2
61 0x30 r3
62 0x34 r12
63 0x38 lr
64 0x3C pc
65 0x40 xPSR
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685. Improving Performance
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70To make ThreadX and the application(s) run faster, you can enable
71all compiler optimizations.
72
73In addition, you can eliminate the ThreadX basic API error checking by
74compiling your application code with the symbol TX_DISABLE_ERROR_CHECKING
75defined.
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786. Interrupt Handling
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80The Cortex-M23 vectors start at the label __vector_table and is typically defined in a
81startup.s file (or similar). The application may modify the vector area according to its needs.
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846.1 Managed Interrupts
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86ISRs for Cortex-M using the IAR tools can be written completely in C (or assembly
87language) without any calls to _tx_thread_context_save or _tx_thread_context_restore.
88These ISRs are allowed access to the ThreadX API that is available to ISRs.
89
90ISRs written in C will take the form (where "your_C_isr" is an entry in the vector table):
91
92void your_C_isr(void)
93{
94
95 /* ISR processing goes here, including any needed function calls. */
96}
97
98ISRs written in assembly language will take the form:
99
100 PUBLIC your_assembly_isr
101your_assembly_isr:
102
103 PUSH {r0, lr}
104
105 ; ISR processing goes here, including any needed function calls.
106
107 POP {r0, r1}
108 MOV lr, r1
109 BX lr
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1127. IAR Thread-safe Library Support
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114Thread-safe support for the IAR tools is easily enabled by building the ThreadX library
115and the application with TX_ENABLE_IAR_LIBRARY_SUPPORT. Also, the linker control file
116should have the following line added (if not already in place):
117
118initialize by copy with packing = none { section __DLIB_PERTHREAD }; // Required in a multi-threaded application
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1217. IAR Thread-safe Library Support
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123Thread-safe support for the IAR tools is easily enabled by building the ThreadX library
124and the application with TX_ENABLE_IAR_LIBRARY_SUPPORT. Also, the linker control file
125should have the following line added (if not already in place):
126
127initialize by copy with packing = none { section __DLIB_PERTHREAD }; // Required in a multi-threaded application
128
129The project options "General Options -> Library Configuration" should also have the
130"Enable thread support in library" box selected.
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1338. Revision History
134
135For generic code revision information, please refer to the readme_threadx_generic.txt
136file, which is included in your distribution. The following details the revision
137information associated with this specific port of ThreadX:
138
13906-02-2021 Release 6.1.7 changes:
140 tx_thread_secure_stack_initialize.s New file
141 tx_thread_schedule.s Added secure stack initialize to SVC hander
142 tx_thread_secure_stack.c Fixed stack pointer save, initialize in handler mode
143
14404-02-2021 Release 6.1.6 changes:
145 tx_port.h Updated macro definition
146 tx_thread_schedule.s Added low power support
147
14803-02-2021 The following files were changed/added for version 6.1.5:
149 tx_port.h Added ULONG64_DEFINED
150
15109-30-2020 Initial ThreadX 6.1 version for Cortex-M23 using IAR's ARM tools.
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154Copyright(c) 1996-2020 Microsoft Corporation
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157https://azure.com/rtos
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