SLAU132Y September   2004  – June 2021

 

  1.   Read This First
    1.     About This Manual
    2.     Notational Conventions
    3.     Related Documentation
    4.     Related Documentation From Texas Instruments
    5.     Trademarks
  2. 1Introduction to the Software Development Tools
    1. 1.1 Software Development Tools Overview
    2. 1.2 Compiler Interface
    3. 1.3 ANSI/ISO Standard
    4. 1.4 Output Files
    5. 1.5 Utilities
  3. 2Using the C/C++ Compiler
    1. 2.1  About the Compiler
    2. 2.2  Invoking the C/C++ Compiler
    3. 2.3  Changing the Compiler's Behavior with Options
      1. 2.3.1  Linker Options
      2. 2.3.2  Frequently Used Options
      3. 2.3.3  Miscellaneous Useful Options
      4. 2.3.4  Run-Time Model Options
      5. 2.3.5  Symbolic Debugging Options
      6. 2.3.6  Specifying Filenames
      7. 2.3.7  Changing How the Compiler Interprets Filenames
      8. 2.3.8  Changing How the Compiler Processes C Files
      9. 2.3.9  Changing How the Compiler Interprets and Names Extensions
      10. 2.3.10 Specifying Directories
      11. 2.3.11 Assembler Options
      12. 2.3.12 Deprecated Options
    4. 2.4  Controlling the Compiler Through Environment Variables
      1. 2.4.1 Setting Default Compiler Options (MSP430_C_OPTION)
      2. 2.4.2 Naming One or More Alternate Directories (MSP430_C_DIR)
    5. 2.5  Controlling the Preprocessor
      1. 2.5.1  Predefined Macro Names
      2. 2.5.2  The Search Path for #include Files
        1. 2.5.2.1 Adding a Directory to the #include File Search Path (--include_path Option)
      3. 2.5.3  Support for the #warning and #warn Directives
      4. 2.5.4  Generating a Preprocessed Listing File (--preproc_only Option)
      5. 2.5.5  Continuing Compilation After Preprocessing (--preproc_with_compile Option)
      6. 2.5.6  Generating a Preprocessed Listing File with Comments (--preproc_with_comment Option)
      7. 2.5.7  Generating Preprocessed Listing with Line-Control Details (--preproc_with_line Option)
      8. 2.5.8  Generating Preprocessed Output for a Make Utility (--preproc_dependency Option)
      9. 2.5.9  Generating a List of Files Included with #include (--preproc_includes Option)
      10. 2.5.10 Generating a List of Macros in a File (--preproc_macros Option)
    6. 2.6  Passing Arguments to main()
    7. 2.7  Understanding Diagnostic Messages
      1. 2.7.1 Controlling Diagnostic Messages
      2. 2.7.2 How You Can Use Diagnostic Suppression Options
    8. 2.8  Other Messages
    9. 2.9  Generating Cross-Reference Listing Information (--gen_cross_reference Option)
    10. 2.10 Generating a Raw Listing File (--gen_preprocessor_listing Option)
    11. 2.11 Using Inline Function Expansion
      1. 2.11.1 Inlining Intrinsic Operators
      2. 2.11.2 Inlining Restrictions
    12. 2.12 Using Interlist
    13. 2.13 Controlling Application Binary Interface
    14. 2.14 Enabling Entry Hook and Exit Hook Functions
  4. 3Optimizing Your Code
    1. 3.1  Invoking Optimization
    2. 3.2  Controlling Code Size Versus Speed
    3. 3.3  Performing File-Level Optimization (--opt_level=3 option)
      1. 3.3.1 Creating an Optimization Information File (--gen_opt_info Option)
    4. 3.4  Program-Level Optimization (--program_level_compile and --opt_level=3 options)
      1. 3.4.1 Controlling Program-Level Optimization (--call_assumptions Option)
      2. 3.4.2 Optimization Considerations When Mixing C/C++ and Assembly
    5. 3.5  Automatic Inline Expansion (--auto_inline Option)
    6. 3.6  Link-Time Optimization (--opt_level=4 Option)
      1. 3.6.1 Option Handling
      2. 3.6.2 Incompatible Types
    7. 3.7  Using Feedback Directed Optimization
      1. 3.7.1 Feedback Directed Optimization
        1. 3.7.1.1 Phase 1 -- Collect Program Profile Information
        2. 3.7.1.2 Phase 2 -- Use Application Profile Information for Optimization
        3. 3.7.1.3 Generating and Using Profile Information
        4. 3.7.1.4 Example Use of Feedback Directed Optimization
        5. 3.7.1.5 The .ppdata Section
        6. 3.7.1.6 Feedback Directed Optimization and Code Size Tune
        7. 3.7.1.7 Instrumented Program Execution Overhead
        8. 3.7.1.8 Invalid Profile Data
      2. 3.7.2 Profile Data Decoder
      3. 3.7.3 Feedback Directed Optimization API
      4. 3.7.4 Feedback Directed Optimization Summary
    8. 3.8  Using Profile Information to Analyze Code Coverage
      1. 3.8.1 Code Coverage
        1. 3.8.1.1 Phase1 -- Collect Program Profile Information
        2. 3.8.1.2 Phase 2 -- Generate Code Coverage Reports
      2. 3.8.2 Related Features and Capabilities
        1. 3.8.2.1 Path Profiler
        2. 3.8.2.2 Analysis Options
        3. 3.8.2.3 Environment Variables
    9. 3.9  Accessing Aliased Variables in Optimized Code
    10. 3.10 Use Caution With asm Statements in Optimized Code
    11. 3.11 Using the Interlist Feature With Optimization
    12. 3.12 Debugging Optimized Code
    13. 3.13 What Kind of Optimization Is Being Performed?
      1. 3.13.1  Cost-Based Register Allocation
      2. 3.13.2  Alias Disambiguation
      3. 3.13.3  Branch Optimizations and Control-Flow Simplification
      4. 3.13.4  Data Flow Optimizations
      5. 3.13.5  Expression Simplification
      6. 3.13.6  Inline Expansion of Functions
      7. 3.13.7  Function Symbol Aliasing
      8. 3.13.8  Induction Variables and Strength Reduction
      9. 3.13.9  Loop-Invariant Code Motion
      10. 3.13.10 Loop Rotation
      11. 3.13.11 Instruction Scheduling
      12. 3.13.12 Tail Merging
      13. 3.13.13 Integer Division With Constant Divisor
  5. 4Linking C/C++ Code
    1. 4.1 Invoking the Linker Through the Compiler (-z Option)
      1. 4.1.1 Invoking the Linker Separately
      2. 4.1.2 Invoking the Linker as Part of the Compile Step
      3. 4.1.3 Disabling the Linker (--compile_only Compiler Option)
    2. 4.2 Linker Code Optimizations
      1. 4.2.1 Conditional Linking
      2. 4.2.2 Generating Aggregate Data Subsections (--gen_data_subsections Compiler Option)
    3. 4.3 Controlling the Linking Process
      1. 4.3.1 Including the Run-Time-Support Library
        1. 4.3.1.1 Automatic Run-Time-Support Library Selection
          1. 4.3.1.1.1 Using the --issue_remarks Option
        2. 4.3.1.2 Manual Run-Time-Support Library Selection
        3. 4.3.1.3 Library Order for Searching for Symbols
      2. 4.3.2 Run-Time Initialization
      3. 4.3.3 Initialization by the Interrupt Vector
      4. 4.3.4 Initialization of the FRAM Memory Protection Unit
      5. 4.3.5 Initialization of Cinit and Watchdog Timer Hold
      6. 4.3.6 Global Object Constructors
      7. 4.3.7 Specifying the Type of Global Variable Initialization
      8. 4.3.8 Specifying Where to Allocate Sections in Memory
      9. 4.3.9 A Sample Linker Command File
  6. 5C/C++ Language Implementation
    1. 5.1  Characteristics of MSP430 C
      1. 5.1.1 Implementation-Defined Behavior
    2. 5.2  Characteristics of MSP430 C++
    3. 5.3  Using the ULP Advisor
    4. 5.4  Advice on Hardware Configuration
    5. 5.5  Data Types
      1. 5.5.1 Size of Enum Types
    6. 5.6  File Encodings and Character Sets
    7. 5.7  Keywords
      1. 5.7.1 The const Keyword
      2. 5.7.2 The __interrupt Keyword
      3. 5.7.3 The restrict Keyword
      4. 5.7.4 The volatile Keyword
    8. 5.8  C++ Exception Handling
    9. 5.9  Register Variables and Parameters
    10. 5.10 The __asm Statement
    11. 5.11 Pragma Directives
      1. 5.11.1  The BIS_IE1_INTERRUPT
      2. 5.11.2  The CALLS Pragma
      3. 5.11.3  The CHECK_ULP Pragma
      4. 5.11.4  The CODE_ALIGN Pragma
      5. 5.11.5  The CODE_SECTION Pragma
      6. 5.11.6  The DATA_ALIGN Pragma
      7. 5.11.7  The DATA_SECTION Pragma
        1. 5.11.7.1 Using the DATA_SECTION Pragma C Source File
        2. 5.11.7.2 Using the DATA_SECTION Pragma C++ Source File
        3. 5.11.7.3 Using the DATA_SECTION Pragma Assembly Source File
      8. 5.11.8  The Diagnostic Message Pragmas
      9. 5.11.9  The FORCEINLINE Pragma
      10. 5.11.10 The FORCEINLINE_RECURSIVE Pragma
      11. 5.11.11 The FUNC_ALWAYS_INLINE Pragma
      12. 5.11.12 The FUNC_CANNOT_INLINE Pragma
      13. 5.11.13 The FUNC_EXT_CALLED Pragma
      14. 5.11.14 The FUNC_IS_PURE Pragma
      15. 5.11.15 The FUNC_NEVER_RETURNS Pragma
      16. 5.11.16 The FUNC_NO_GLOBAL_ASG Pragma
      17. 5.11.17 The FUNC_NO_IND_ASG Pragma
      18. 5.11.18 The FUNCTION_OPTIONS Pragma
      19. 5.11.19 The INTERRUPT Pragma
      20. 5.11.20 The LOCATION Pragma
      21. 5.11.21 The MUST_ITERATE Pragma
        1. 5.11.21.1 The MUST_ITERATE Pragma Syntax
        2. 5.11.21.2 Using MUST_ITERATE to Expand Compiler Knowledge of Loops
      22. 5.11.22 The NOINIT and PERSISTENT Pragmas
      23. 5.11.23 The NOINLINE Pragma
      24. 5.11.24 The NO_HOOKS Pragma
      25. 5.11.25 The once Pragma
      26. 5.11.26 The pack Pragma
      27. 5.11.27 The PROB_ITERATE Pragma
      28. 5.11.28 The RESET_ULP Pragma
      29. 5.11.29 The RETAIN Pragma
      30. 5.11.30 The SET_CODE_SECTION and SET_DATA_SECTION Pragmas
      31. 5.11.31 The UNROLL Pragma
      32. 5.11.32 The vector Pragma
      33. 5.11.33 The WEAK Pragma
    12. 5.12 The _Pragma Operator
    13. 5.13 Application Binary Interface
    14. 5.14 Object File Symbol Naming Conventions (Linknames)
    15. 5.15 Changing the ANSI/ISO C/C++ Language Mode
      1. 5.15.1 C99 Support (--c99)
      2. 5.15.2 C11 Support (--c11)
      3. 5.15.3 Strict ANSI Mode and Relaxed ANSI Mode (--strict_ansi and --relaxed_ansi)
    16. 5.16 GNU and Clang Language Extensions
      1. 5.16.1 Extensions
      2. 5.16.2 Function Attributes
      3. 5.16.3 For Loop Attributes
      4. 5.16.4 Variable Attributes
      5. 5.16.5 Type Attributes
      6. 5.16.6 Built-In Functions
    17. 5.17 Compiler Limits
  7. 6Run-Time Environment
    1. 6.1  Memory Model
      1. 6.1.1 Code Memory Models
      2. 6.1.2 Data Memory Models
      3. 6.1.3 Support for Near Data
      4. 6.1.4 Sections
      5. 6.1.5 C/C++ Software Stack
      6. 6.1.6 Dynamic Memory Allocation
    2. 6.2  Object Representation
      1. 6.2.1 Data Type Storage
        1. 6.2.1.1 Pointer to Member Function Types
        2. 6.2.1.2 Structure and Array Alignment
        3. 6.2.1.3 Field/Structure Alignment
        4. 6.2.1.4 C Code Definition of var
      2. 6.2.2 Character String Constants
    3. 6.3  Register Conventions
    4. 6.4  Function Structure and Calling Conventions
      1. 6.4.1 How a Function Makes a Call
      2. 6.4.2 How a Called Function Responds
      3. 6.4.3 Accessing Arguments and Local Variables
    5. 6.5  Accessing Linker Symbols in C and C++
    6. 6.6  Interfacing C and C++ With Assembly Language
      1. 6.6.1 Using Assembly Language Modules With C/C++ Code
      2. 6.6.2 Accessing Assembly Language Functions From C/C++
        1. 6.6.2.1 Calling an Assembly Language Function From a C/C++ Program
        2. 6.6.2.2 Assembly Language Program Called by Section 1
        3.       227
      3. 6.6.3 Accessing Assembly Language Variables From C/C++
        1. 6.6.3.1 Accessing Assembly Language Global Variables
          1. 6.6.3.1.1 Assembly Language Variable Program
          2. 6.6.3.1.2 C Program to Access Assembly Language From Section 1
        2.       232
        3. 6.6.3.2 Accessing Assembly Language Constants
          1. 6.6.3.2.1 Accessing an Assembly Language Constant From C
          2. 6.6.3.2.2 Assembly Language Program for Section 1
          3.        236
      4. 6.6.4 Sharing C/C++ Header Files With Assembly Source
      5. 6.6.5 Using Inline Assembly Language
    7. 6.7  Interrupt Handling
      1. 6.7.1 Saving Registers During Interrupts
      2. 6.7.2 Using C/C++ Interrupt Routines
        1.       242
      3. 6.7.3 Using Assembly Language Interrupt Routines
      4. 6.7.4 Interrupt Vectors
      5. 6.7.5 Other Interrupt Information
    8. 6.8  Using Intrinsics to Access Assembly Language Statements
      1. 6.8.1 MSP430 Intrinsics
      2. 6.8.2 Floating Point Conversion Intrinsics
      3. 6.8.3 Deprecated Intrinsics
      4. 6.8.4 The __delay_cycle Intrinsic
      5. 6.8.5 The __never_executed Intrinsic
        1. 6.8.5.1 Using __never_executed With a Vector Generator
          1. 6.8.5.1.1 TBIV Vector Generator
          2.        254
        2. 6.8.5.2 Using __never_executed With General Switch Expressions
          1. 6.8.5.2.1 General Switch Statement
          2.        257
    9. 6.9  System Initialization
      1. 6.9.1 Boot Hook Functions for System Pre-Initialization
      2. 6.9.2 Run-Time Stack
      3. 6.9.3 Automatic Initialization of Variables
        1. 6.9.3.1 Zero Initializing Variables
        2. 6.9.3.2 Direct Initialization
        3. 6.9.3.3 Autoinitialization of Variables at Run Time
        4. 6.9.3.4 Autoinitialization Tables
          1. 6.9.3.4.1 Length Followed by Data Format
          2. 6.9.3.4.2 Zero Initialization Format
          3. 6.9.3.4.3 Run Length Encoded (RLE) Format
          4. 6.9.3.4.4 Lempel-Ziv-Storer-Szymanski Compression (LZSS) Format
        5. 6.9.3.5 Initialization of Variables at Load Time
        6. 6.9.3.6 Global Constructors
      4. 6.9.4 Initialization Tables
    10. 6.10 Compiling for 20-Bit MSP430X Devices
  8. 7Using Run-Time-Support Functions and Building Libraries
    1. 7.1 C and C++ Run-Time Support Libraries
      1. 7.1.1 Linking Code With the Object Library
      2. 7.1.2 Header Files
      3. 7.1.3 Modifying a Library Function
      4. 7.1.4 Support for String Handling
      5. 7.1.5 Minimal Support for Internationalization
      6. 7.1.6 Support for Time and Clock Functions
      7. 7.1.7 Allowable Number of Open Files
      8. 7.1.8 Nonstandard Header Files in the Source Tree
      9. 7.1.9 Library Naming Conventions
    2. 7.2 The C I/O Functions
      1. 7.2.1 High-Level I/O Functions
        1. 7.2.1.1 Formatting and the Format Conversion Buffer
      2. 7.2.2 Overview of Low-Level I/O Implementation
        1.       open
        2.       close
        3.       read
        4.       write
        5.       lseek
        6.       unlink
        7.       rename
      3. 7.2.3 Device-Driver Level I/O Functions
        1.       DEV_open
        2.       DEV_close
        3.       DEV_read
        4.       DEV_write
        5.       DEV_lseek
        6.       DEV_unlink
        7.       DEV_rename
      4. 7.2.4 Adding a User-Defined Device Driver for C I/O
        1. 7.2.4.1 Mapping Default Streams to Device
      5. 7.2.5 The device Prefix
        1.       add_device
        2.       308
        3. 7.2.5.1 Program for C I/O Device
    3. 7.3 Handling Reentrancy (_register_lock() and _register_unlock() Functions)
    4. 7.4 Library-Build Process
      1. 7.4.1 Required Non-Texas Instruments Software
      2. 7.4.2 Using the Library-Build Process
        1. 7.4.2.1 Automatic Standard Library Rebuilding by the Linker
        2. 7.4.2.2 Invoking mklib Manually
          1. 7.4.2.2.1 Building Standard Libraries
          2. 7.4.2.2.2 Shared or Read-Only Library Directory
          3. 7.4.2.2.3 Building Libraries With Custom Options
          4. 7.4.2.2.4 The mklib Program Option Summary
      3. 7.4.3 Extending mklib
        1. 7.4.3.1 Underlying Mechanism
        2. 7.4.3.2 Libraries From Other Vendors
  9. 8C++ Name Demangler
    1. 8.1 Invoking the C++ Name Demangler
    2. 8.2 Sample Usage of the C++ Name Demangler
  10.   A Glossary
    1.     A.1 Terminology
  11.   B Revision History
  12.   329
  13.   330

2.3.4 Run-Time Model Options

These options are specific to the MSP430 toolset. See the referenced sections for more information. MSP430-specific assembler options are listed in Section 3.4.11.

The MSP430 compiler now supports only the Embedded Application Binary Interface (EABI) ABI, which uses the ELF object format and the DWARF debug format. If you want support for the legacy COFF ABI, please use the MSP430 v4.4 Code Generation Tools and refer to SLAU132J and SLAU131J for documentation.

--common={on|off} When on (the default ), uninitialized file scope variables are emitted as common symbols. When off, common symbols are not created. The benefit of allowing common symbols to be created is that generated code can remove unused variables that would otherwise increase the size of the .bss section. (Uninitialized variables of a size larger than 32 bytes are separately optimized through placement in separate subsections that can be omitted from a link.) Variables cannot be common symbols if they are assigned to a section other than .bss .
--code_model={large|small} Specifies the code memory model: small (16-bit function pointers and low 64K memory) or large (20-bit function pointers and 1MB address space). See Section 7.2.1 for details.
--data_model={restricted|large|
small}		 Specifies the data memory model: small (16-bit data pointers and low 64K memory), restricted (32-bit data pointers, objects restricted to 64K, and 1MB memory), and large (32-bit data pointers and 1MB memory). See Section 7.2.2 for details.
--disable_interrupts_around_hw_mpy=off Setting this option to off leaves interrupts enabled during inlined hardware multiplication. (Inlined hardware multiplication is controlled by the --use_hw_mpy and --opt_for_speed options.)

This option should only be used if all ISRs in the application do not use multiplication and do not call other functions. By default, if hardware multiplication is inlined, interrupts are disabled during hardware multiplication, because such operations are not re-entrant.

If this option is set to off and an ISR uses multiplication, the linker issues a warning that multiplication within the ISR will use the RTS software multiply routine instead of the RTS hardware multiply routine.

If this option is set to off and an ISR calls other functions, the linker generates a non-fatal error diagnostic indicating that the option --disable_interrupts_around_hw_mpy=off cannot be used if the application includes ISRs with calls to other functions. The reason for this is that if an ISR calls a routine that does multiplication using the hardware multiplier, then the inlined hardware multipliers with interrupts left enabled are no longer safe.
--enum_type={packed|unpacked} By default, the compiler uses --enum_type=unpacked, which means the compiler uses an integer type no smaller than 16 bits (int, long, or long long) to store enumerated type variables. The --enum_type=packed option causes the compiler to use an 8-bit integer type if the enumeration constant values can fit into that 8-bit type. For details about enumerated type sizes, see Section 6.6.1.

Do not link object files compiled with the --enum_type=packed option with object files that have been compiled without it. If you are using the --enum_type=packed option, you must use it consistently to compile all of your C/C++ files; otherwise, you will encounter errors that cannot be detected until run-time.

--large_memory_model This option is deprecated. Use --data_model=large.
--near_data={globals|none} Specifies that global read/write data must be located in the first 64K of memory. See Section 7.2.3 for details.
--pending_instantiations=# Specify the number of template instantiations that may be in progress at any given time. Use 0 to specify an unlimited number.
--plain_char={unsigned|signed} Specifies how to treat C/C++ plain char variables. Default is unsigned.
--ramfunc={on|off} If set to on, specifies that all functions should be placed in the .TI.ramfunc section, which is placed in RAM. If set to off, only functions with the ramfunc function attribute are treated this way. See Section 6.17.2.

Newer TI linker command files support the --ramfunc option automatically by placing functions in the .TI.ramfunc section. If you have a linker command file that does not include a section specification for the .TI.ramfunc section, you can modify the linker command file to place this section in RAM. See the MSP430 Assembly Language Tools User's Guide for details on section placement.
--silicon_version Selects the instruction set version. Using --silicon_version=mspx generates code for MSP430X devices (20-bit code addressing). Using --silicon_version=msp generates code for 16-bit MSP430 devices.

Modules assembled/compiled for 16-bit MSP430 devices are not compatible with modules that are assembled/compiled for 20-bit MSPx devices. The linker generates errors if an attempt is made to combine incompatible object files.
--use_hw_mpy[= 16,32,F5,none] This option is a compiler option. It should be placed on the command line before the -z option.

MSP430 devices do not have a multiply instruction, and some devices have no hardware multiply at all. Multiplication is performed by a library function that either uses the hardware multiply capability or simulates it in software. By default, the compiler generates references to the version that does not use the hardware multiplier peripheral that is available on some versions of the MSP430 device. If your MSP430 device has multiply hardware, you can choose to use the library routine matching your hardware for best performance. When compiling for a device where the hardware multiplier is available, use the --use_hw_mpy compiler option.

At compile time, using this option causes hardware multiply calls to be inlined during code generation if --opt_for_speed is set to 4 or 5 and --opt_level is set to any value other than "off". See the --disable_interrupts_around_hw_mpy=off option if you want to control whether interrupts are enabled during inlined hardware multiplication.

If inlining is not enabled but other optimization is enabled (--opt_for_speed is set to 1, 2, or 3), using this option causes the linker to replace all references to the default multiply routine with the version of the multiply routine that uses the hardware multiplier support.

The optional argument indicates which version of the hardware multiply is being used and must be one of the following:

  • 16 uses the F1xx/2xx/4xx family 16-bit hardware multiplier (default)
  • 32 uses the F4xx 32-bit hardware multiplier
  • F5 uses the F5xx/6xx family 32-bit hardware multiplier
  • none = does not use a hardware multiplier

For more information regarding the hardware multiplier, see the Family User’s Guide for the MSP430x1xx, MSP430x3xx, MSP430x4xx, and MSP430x5xx.