SPRU514Z July   2001  – October 2023 SM320F28335-EP

 

  1.   1
  2.   Read This First
    1.     About This Manual
    2.     Notational Conventions
    3.     Related Documentation
    4.     Related Documentation From Texas Instruments
    5.     Trademarks
  3. 1 Introduction 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
  4. 2 Using 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 and Profiling 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 (C2000_C_OPTION)
      2. 2.4.2 Naming One or More Alternate Directories (C2000_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_listing 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
      3. 2.11.3 Unguarded Definition-Controlled Inlining
        1. 2.11.3.1 Using the Inline Keyword
      4. 2.11.4 Guarded Inlining and the _INLINE Preprocessor Symbol
        1. 2.11.4.1 Header File string.h
        2. 2.11.4.2 Library Definition File
    12. 2.12 Using Interlist
    13. 2.13 About the Application Binary Interface
    14. 2.14 Enabling Entry Hook and Exit Hook Functions
    15. 2.15 Live Firmware Update (LFU)
  5. 3 Optimizing 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  Special Considerations When Using Optimization
      1. 3.9.1 Use Caution With asm Statements in Optimized Code
      2. 3.9.2 Use the Volatile Keyword for Necessary Memory Accesses
        1. 3.9.2.1 Use Caution When Accessing Aliased Variables
        2. 3.9.2.2 Use the --aliased_variables Option to Indicate That the Following Technique Is Used
        3. 3.9.2.3 On FPU Targets Only: Use restrict Keyword to Indicate That Pointers Are Not Aliased
          1. 3.9.2.3.1 Use of the restrict Type Qualifier With Pointers
          2. 3.9.2.3.2 Use of the restrict Type Qualifier With Pointers
    10. 3.10 Using the Interlist Feature With Optimization
    11. 3.11 Data Page (DP) Pointer Load Optimization
    12. 3.12 Debugging and Profiling Optimized Code
      1. 3.12.1 Profiling Optimized Code
    13. 3.13 Increasing Code-Size Optimizations (--opt_for_space Option)
    14. 3.14 Compiler Support for Re-Entrant VCU Code
    15. 3.15 Compiler Support for Generating DMAC Instructions
      1. 3.15.1 Automatic Generation of DMAC Instructions
      2. 3.15.2 Assertions to Specify Data Address Alignment
      3. 3.15.3 __dmac Intrinsic
    16. 3.16 What Kind of Optimization Is Being Performed?
      1. 3.16.1  Cost-Based Register Allocation
      2. 3.16.2  Alias Disambiguation
      3. 3.16.3  Branch Optimizations and Control-Flow Simplification
      4. 3.16.4  Data Flow Optimizations
      5. 3.16.5  Expression Simplification
      6. 3.16.6  Inline Expansion of Functions
      7. 3.16.7  Function Symbol Aliasing
      8. 3.16.8  Induction Variables and Strength Reduction
      9. 3.16.9  Loop-Invariant Code Motion
      10. 3.16.10 Loop Rotation
      11. 3.16.11 Instruction Scheduling
      12. 3.16.12 Register Variables
      13. 3.16.13 Register Tracking/Targeting
      14. 3.16.14 Tail Merging
      15. 3.16.15 Autoincrement Addressing
      16. 3.16.16 Removing Comparisons to Zero
      17. 3.16.17 RPTB Generation (for FPU Targets Only)
  6. 4 Linking 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 Generating Function Subsections (--gen_func_subsections Compiler Option)
      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 Global Object Constructors
      5. 4.3.5 Specifying the Type of Global Variable Initialization
      6. 4.3.6 Specifying Where to Allocate Sections in Memory
      7. 4.3.7 A Sample Linker Command File
    4. 4.4 Linking C28x and C2XLP Code
  7. 5 Post-Link Optimizer
    1. 5.1 The Post-Link Optimizer’s Role in the Software Development Flow
    2. 5.2 Removing Redundant DP Loads
    3. 5.3 Tracking DP Values Across Branches
    4. 5.4 Tracking DP Values Across Function Calls
    5. 5.5 Other Post-Link Optimizations
    6. 5.6 Controlling Post-Link Optimizations
      1. 5.6.1 Excluding Files (-ex Option)
      2. 5.6.2 Controlling Post-Link Optimization Within an Assembly File
      3. 5.6.3 Retaining Post-Link Optimizer Output (--keep_asm Option)
      4. 5.6.4 Disable Optimization Across Function Calls (-nf Option )
      5. 5.6.5 Annotating Assembly with Advice (--plink_advice_only option)
    7. 5.7 Restrictions on Using the Post-Link Optimizer
    8. 5.8 Naming the Outfile (--output_file Option)
  8. 6 C/C++ Language Implementation
    1. 6.1  Characteristics of TMS320C28x C
      1. 6.1.1 Implementation-Defined Behavior
    2. 6.2  Characteristics of TMS320C28x C++
    3. 6.3  Data Types
      1. 6.3.1 Size of Enum Types
      2. 6.3.2 Support for 64-Bit Integers
      3. 6.3.3 C28x double and long double Floating-Point Types
    4. 6.4  File Encodings and Character Sets
    5. 6.5  Keywords
      1. 6.5.1 The const Keyword
      2. 6.5.2 The __cregister Keyword
      3. 6.5.3 The __interrupt Keyword
      4. 6.5.4 The restrict Keyword
      5. 6.5.5 The volatile Keyword
    6. 6.6  C++ Exception Handling
    7. 6.7  Register Variables and Parameters
    8. 6.8  The __asm Statement
    9. 6.9  Pragma Directives
      1. 6.9.1  The CALLS Pragma
      2. 6.9.2  The CLINK Pragma
      3. 6.9.3  The CODE_ALIGN Pragma
      4. 6.9.4  The CODE_SECTION Pragma
      5. 6.9.5  The DATA_ALIGN Pragma
      6. 6.9.6  The DATA_SECTION Pragma
        1. 6.9.6.1 Using the DATA_SECTION Pragma C Source File
        2. 6.9.6.2 Using the DATA_SECTION Pragma C++ Source File
        3. 6.9.6.3 Using the DATA_SECTION Pragma Assembly Source File
      7. 6.9.7  The Diagnostic Message Pragmas
      8. 6.9.8  The FAST_FUNC_CALL Pragma
      9. 6.9.9  The FORCEINLINE Pragma
      10. 6.9.10 The FORCEINLINE_RECURSIVE Pragma
      11. 6.9.11 The FUNC_ALWAYS_INLINE Pragma
      12. 6.9.12 The FUNC_CANNOT_INLINE Pragma
      13. 6.9.13 The FUNC_EXT_CALLED Pragma
      14. 6.9.14 The FUNCTION_OPTIONS Pragma
      15. 6.9.15 The INTERRUPT Pragma
      16. 6.9.16 The LOCATION Pragma
      17. 6.9.17 The MUST_ITERATE Pragma
        1. 6.9.17.1 The MUST_ITERATE Pragma Syntax
        2. 6.9.17.2 Using MUST_ITERATE to Expand Compiler Knowledge of Loops
      18. 6.9.18 The NOINIT and PERSISTENT Pragmas
      19. 6.9.19 The NOINLINE Pragma
      20. 6.9.20 The NO_HOOKS Pragma
      21. 6.9.21 The once Pragma
      22. 6.9.22 The RETAIN Pragma
      23. 6.9.23 The SET_CODE_SECTION and SET_DATA_SECTION Pragmas
      24. 6.9.24 The UNROLL Pragma
      25. 6.9.25 The WEAK Pragma
    10. 6.10 The _Pragma Operator
    11. 6.11 Application Binary Interface
    12. 6.12 Object File Symbol Naming Conventions (Linknames)
    13. 6.13 Initializing Static and Global Variables in COFF ABI Mode
      1. 6.13.1 Initializing Static and Global Variables With the Linker
      2. 6.13.2 Initializing Static and Global Variables With the const Type Qualifier
    14. 6.14 Changing the ANSI/ISO C/C++ Language Mode
      1. 6.14.1 C99 Support (--c99)
      2. 6.14.2 C11 Support (--c11)
      3. 6.14.3 Strict ANSI Mode and Relaxed ANSI Mode (--strict_ansi and --relaxed_ansi)
    15. 6.15 GNU and Clang Language Extensions
      1. 6.15.1 Extensions
      2. 6.15.2 Function Attributes
      3. 6.15.3 For Loop Attributes
      4. 6.15.4 Variable Attributes
      5. 6.15.5 Type Attributes
      6. 6.15.6 Built-In Functions
      7. 6.15.7 Using the Byte Peripheral Type Attribute
    16. 6.16 Compiler Limits
  9. 7 Run-Time Environment
    1. 7.1  Memory Model
      1. 7.1.1 Sections
      2. 7.1.2 C/C++ System Stack
      3. 7.1.3 Allocating .econst to Program Memory
      4. 7.1.4 Dynamic Memory Allocation
      5. 7.1.5 Initialization of Variables
      6. 7.1.6 Allocating Memory for Static and Global Variables
      7. 7.1.7 Field/Structure Alignment
      8. 7.1.8 Character String Constants
    2. 7.2  Register Conventions
      1. 7.2.1 TMS320C28x Register Use and Preservation
      2. 7.2.2 Status Registers
    3. 7.3  Function Structure and Calling Conventions
      1. 7.3.1 How a Function Makes a Call
      2. 7.3.2 How a Called Function Responds
      3. 7.3.3 Special Case for a Called Function (Large Frames)
      4. 7.3.4 Accessing Arguments and Local Variables
      5. 7.3.5 Allocating the Frame and Accessing 32-Bit Values in Memory
    4. 7.4  Accessing Linker Symbols in C and C++
    5. 7.5  Interfacing C and C++ With Assembly Language
      1. 7.5.1 Using Assembly Language Modules With C/C++ Code
      2. 7.5.2 Accessing Assembly Language Functions From C/C++
        1. 7.5.2.1 Calling an Assembly Language Function From a C/C++ Program
        2. 7.5.2.2 Assembly Language Program Called by
        3.       261
      3. 7.5.3 Accessing Assembly Language Variables From C/C++
        1. 7.5.3.1 Accessing Assembly Language Global Variables
          1. 7.5.3.1.1 Assembly Language Variable Program
          2. 7.5.3.1.2 C Program to Access Assembly Language From
        2.       266
        3. 7.5.3.2 Accessing Assembly Language Constants
          1. 7.5.3.2.1 Accessing an Assembly Language Constant From C
          2. 7.5.3.2.2 Assembly Language Program for
          3.        270
      4. 7.5.4 Sharing C/C++ Header Files With Assembly Source
      5. 7.5.5 Using Inline Assembly Language
    6. 7.6  Using Intrinsics to Access Assembly Language Statements
      1. 7.6.1 Floating Point Conversion Intrinsics
      2. 7.6.2 Floating Point Unit (FPU) Intrinsics
      3. 7.6.3 Trigonometric Math Unit (TMU) Intrinsics
      4. 7.6.4 Fast Integer Division Intrinsics
    7. 7.7  Interrupt Handling
      1. 7.7.1 General Points About Interrupts
      2. 7.7.2 Using C/C++ Interrupt Routines
    8. 7.8  Integer Expression Analysis
      1. 7.8.1 Operations Evaluated With Run-Time-Support Calls
      2. 7.8.2 Division Operations with Fast Integer Division Support
      3. 7.8.3 C/C++ Code Access to the Upper 16 Bits of 16-Bit Multiply
    9. 7.9  Floating-Point Expression Analysis
    10. 7.10 System Initialization
      1. 7.10.1 Boot Hook Functions for System Pre-Initialization
      2. 7.10.2 Run-Time Stack
      3. 7.10.3 Automatic Initialization of Variables for COFF
        1. 7.10.3.1 Initialization Tables
        2.       291
        3. 7.10.3.2 Autoinitialization of Variables at Run Time for COFF
        4. 7.10.3.3 Initialization of Variables at Load Time for COFF
        5. 7.10.3.4 Global Constructors
      4. 7.10.4 Automatic Initialization of Variables for EABI
        1. 7.10.4.1 Zero Initializing Variables
        2. 7.10.4.2 Direct Initialization for EABI
        3. 7.10.4.3 Autoinitialization of Variables at Run Time for EABI
        4. 7.10.4.4 Autoinitialization Tables for EABI
          1. 7.10.4.4.1 Length Followed by Data Format
          2. 7.10.4.4.2 Zero Initialization Format
          3. 7.10.4.4.3 Run Length Encoded (RLE) Format
          4. 7.10.4.4.4 Lempel-Ziv-Storer-Szymanski Compression (LZSS) Format
        5. 7.10.4.5 Initialization of Variables at Load Time
        6. 7.10.4.6 Global Constructors
  10. 8 Using Run-Time-Support Functions and Building Libraries
    1. 8.1 C and C++ Run-Time Support Libraries
      1. 8.1.1 Linking Code With the Object Library
      2. 8.1.2 Header Files
      3. 8.1.3 Modifying a Library Function
      4. 8.1.4 Support for String Handling
      5. 8.1.5 Minimal Support for Internationalization
      6. 8.1.6 Support for Time and Clock Functions
      7. 8.1.7 Allowable Number of Open Files
      8. 8.1.8 Library Naming Conventions
    2. 8.2 The C I/O Functions
      1. 8.2.1 High-Level I/O Functions
        1. 8.2.1.1 Formatting and the Format Conversion Buffer
      2. 8.2.2 Overview of Low-Level I/O Implementation
        1.       open
        2.       close
        3.       read
        4.       write
        5.       lseek
        6.       unlink
        7.       rename
      3. 8.2.3 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. 8.2.4 Adding a User-Defined Device Driver for C I/O
        1. 8.2.4.1 Mapping Default Streams to Device
      5. 8.2.5 The device Prefix
        1.       add_device
        2.       339
        3. 8.2.5.1 Program for C I/O Device
    3. 8.3 Handling Reentrancy (_register_lock() and _register_unlock() Functions)
    4. 8.4 Reinitializing Variables During a Warm Start
    5. 8.5 Library-Build Process
      1. 8.5.1 Required Non-Texas Instruments Software
      2. 8.5.2 Using the Library-Build Process
        1. 8.5.2.1 Automatic Standard Library Rebuilding by the Linker
        2. 8.5.2.2 Invoking mklib Manually
          1. 8.5.2.2.1 Building Standard Libraries
          2. 8.5.2.2.2 Shared or Read-Only Library Directory
          3. 8.5.2.2.3 Building Libraries With Custom Options
          4. 8.5.2.2.4 The mklib Program Option Summary
      3. 8.5.3 Extending mklib
        1. 8.5.3.1 Underlying Mechanism
        2. 8.5.3.2 Libraries From Other Vendors
  11. 9 C++ Name Demangler
    1. 9.1 Invoking the C++ Name Demangler
    2. 9.2 Sample Usage of the C++ Name Demangler
  12. 10CLA Compiler
    1. 10.1 How to Invoke the CLA Compiler
      1. 10.1.1 CLA-Specific Options
    2. 10.2 CLA C Language Implementation
      1. 10.2.1 Variables and Data Types
      2. 10.2.2 Pragmas, Keywords, and Intrinsics
      3. 10.2.3 Optimizations with the CLA Compiler
      4. 10.2.4 C Language Restrictions
      5. 10.2.5 Memory Model - Sections
      6. 10.2.6 Function Structure and Calling Conventions
  13.   A Glossary
    1.     369
  14.   B Revision History
  15.   B Earlier Revisions

2.3.4 Run-Time Model Options

These options are specific to the TMS320C28x toolset. See the referenced sections for more information. TMS320C28x-specific assembler options are listed in Section 2.3.11.

The C28x compiler supports both the COFF ABI and the Embedded Application Binary Interface (EABI) ABI. EABI uses the ELF object format and the DWARF debug format.

--abi={eabi|coffabi} Specifies the application binary interface (ABI). The default ABI is COFF. EABI is also supported. See Section 2.13. Refer to the C28x Embedded Application Binary Interface (SPRAC71) application report.

All code in an EABI application must be built for EABI. Make sure all your libraries are available in EABI mode before migrating your existing COFF ABI systems to EABI.
--cla_support={cla0|cla1|cla2} Specifies TMS320C28x Control Law Accelerator (CLA) Type 0, Type 1, or Type 2 support. This option is used to compile or assemble code written for the CLA. This option does not require any special library support when linking; the libraries used for C28x with/without FPU support should be sufficient.
--float_support={ fpu32 | fpu64 | softlib } Specifies use of TMS320C28x 32-bit or 64-bit hardware floating-point support. Using --float_support=fpu32 specifies the C28x architecture with 32-bit hardware floating-point support. Using --float_support=fpu64 specifies the C28x architecture with 64-bit hardware floating-point support. FPU64 is supported only when using EABI.
If the --tmu_support option is used to enable support for the Trigonometric Math Unit, the --float_support option is automatically set to fpu32. The default is softlib, which performs floating-point calculations without special hardware support.
--idiv_support={ none | idiv0 } Enables support for fast integer division using hardware extensions to provide a set of instructions to accelerate integer division. If this hardware is available, use --idiv_support=idiv0 to cause these instructions to be used. The default is none. Datasheets for devices that include this hardware contain the words "Support for Fast Integer Division (FINTDIV)." (EABI only.)

When this option is enabled, the built-in integer division and modulo operators ("/" and "%") use the appropriate faster instructions. See Section 7.8.2 for more about such cases.

When this option is enabled, you can also use the fast integer division intrinsics described in Section 7.6.4. In order to use these intrinsics, your code must include the stdlib.h header file.
--no_rpt Prevents the compiler from generating repeat (RPT) instructions. By default, repeat instructions are generated for certain memcpy, division, and multiply-accumulate operations. However, repeat instructions are not interruptible.
--pending_instantiations=# Specify the number of template instantiations that may be in progress at any given time. Use 0 to specify an unlimited number.
--protect_volatile=num Enables volatile reference protection. Pipeline conflicts may occur between non-local variables that have been declared volatile. A conflict can occur between a write to one volatile variable that is followed by a read from a different volatile variable. The --protect_volatile option allows at least num instructions to be placed between the two volatile references to ensure the write occurs before the read. The num is optional. If no num is given, the default value is 2. For example, if --protect_volatile=4 is used, volatile writes and volatile reads are protected by at least 4 instructions.

The peripheral pipeline protection hardware protects all internal peripherals and XINTF zone 1. If you connect peripherals to Xintf zone 0, 2, 6, 7 then you may need to use the --protect_volatile option. Hardware protection or using this option is not required for memories.
--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 6.15.2.
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 TMS320C28x Assembly Language Tools User's Guide for details on section placement.
--rpt_threshold=k Generates RPT loops that iterate k times or less (k is a constant between 0 and 256). Multiple RPT’s may be generated for the same loop, if iteration count is more than k and if code size does not increase too much. Using this option when optimizing for code size disables RPT loop generation for loops whose iteration count can be greater than k.
Note that inlined memcpy calls now support >255 words through the use of RPT with a register operand. This allows inlining of memcpy of up to 65535 words. If you set the --no_rpt or --rpt_threshold option, such inlining is disabled or reduced, respectively. The maximum value that may be specified with --rpt_threshold is still 256.
--silicon_errata_fpu1_
workaround=on|off		 Enabling this option prevents FPU register write conflicts that can occur during certain instructions. CPU-to-FPU register writes cannot occur during FRACF32, F32TOUI32, or UI16TOF32 instructions. If you enable this option, the compiler adds five NOP instructions before these instructions to prevent conflicts.
This option is disabled by default if any of the following options are enabled: --float_support=fpu64, --tmu_support, or --vcu_support=vcu2|vcrc.
--silicon_version=28 Generates code for the TMS320C28x architecture. The only value accepted is 28. This is the default, so this option is no longer required on command lines.
--unified_memory Use the --unified_memory (-mt) option if your memory map is configured as a single unified space; this allows the compiler to generate RPT PREAD instructions for most memcpy calls and structure assignments. This also allows MAC instructions to be generated. The --unified_memory option also allows more efficient data memory instructions to be used to access switch tables. Even with unified memory, memory for some peripherals and some RAM associated with those peripherals is allocated only in data memory.
If –unified_memory is enabled, you can prevent program memory address access to specific symbols by declaring symbols as volatile. Struct assigns between volatile and non-volatile symbols have different effects on the instructions used depending on the direction of the assignment. Struct assigns from non-volatile to volatile can use RPT with PREAD, which uses the program bus to read the non-volatile source operand. Struct assigns from volatile to non-volatile can use RPT with PWRITE, which uses the program bus to write to the non-volatile destination operand.
--tmu_support[=tmu0|tmu1] Enables support for the Trigonometric Math Unit (TMU). Using this option automatically enables FPU32 support (as with the --float_support=fpu32 option). When TMU support is enabled, intrinsics are available to perform trigonometric instructions on the TMU.
There are algorithmic differences between the TMU hardware instructions and the library routines, so the results of operations may differ slightly.
The tmu1 setting is available with EABI only. The tmu1 setting adds support for the LOG2F32 and IEXP2F32 intrinsics in addition to the intrinsics supported with the tmu0 setting.
In relaxed floating point mode, RTS library calls are replaced with the corresponding TMU hardware instructions for the following floating-point operations: floating point division, sqrt, sin, cos, atan, and atan2. Additionally, if the --tmu_support=tmu1 option is used with --fp_mode=relaxed, special versions of the following 32-bit float math functions are used: exp2f(), expf(), log2f(), logf(), and powf(). Relaxed versions that work with EABI's 64-bit double types are not provided.
--vcu_support[=vcu0|vcu2|vcrc] The vcu0 and vcu2 settings specify there is support for Type 0 or Type 2 of the Viterbi, Complex Math and CRC Unit (VCU). Note that there is no VCU Type 1. The default is vcu0.
The vcrc setting specifies support for Cyclic Redundancy Check (CRC) algorithms only. Support for vcrc is available only if FPU32 or FPU64 is used.
This option is useful only if the source is in assembly code, written for the VCU. The option is ignored for C/C++ code. This option does not need any special library support when linking; the libraries used for C28x with/without VCU support should be sufficient. Also note that there is no VCU Type 1.