米6体育平台手机版

SPRU513Y August 2001 – June 2022 SM320F28335-EP

Read This First
1. About This Manual
2. How to Use This Manual
3. Notational Conventions
4. Related Documentation From Texas Instruments
5. Trademarks
1 Introduction to the Software Development Tools
1. 1.1 Software Development Tools Overview
2. 1.2 Tools Descriptions
2 Introduction to Object Modules
1. 2.1 Object File Format Specifications
2. 2.2 Executable Object Files
3. 2.3 Introduction to Sections
  1. 2.3.1 Special Section Names
4. 2.4 How the Assembler Handles Sections
5. 2.5 How the Linker Handles Sections
  1. 2.5.1 Combining Input Sections
  2. 2.5.2 Placing Sections
6. 2.6 Symbols
7. 2.7 Symbolic Relocations
  1. 2.7.1 Expressions With Multiple Relocatable Symbols (COFF Only)
8. 2.8 Loading a Program
3 Program Loading and Running
1. 3.1 Loading
  1. 3.1.1 Load and Run Addresses
  2. 3.1.2 Bootstrap Loading
2. 3.2 Entry Point
3. 3.3 Run-Time Initialization
4. 3.4 Arguments to main
5. 3.5 Run-Time Relocation
6. 3.6 Additional Information
4 Assembler Description
1. 4.1 Assembler Overview
2. 4.2 The Assembler's Role in the Software Development Flow
3. 4.3 Invoking the Assembler
4. 4.4 Controlling Application Binary Interface
5. 4.5 Naming Alternate Directories for Assembler Input
  1. 4.5.1 Using the --include_path Assembler Option
  2. 4.5.2 Using the C2000_A_DIR Environment Variable
6. 4.6 Source Statement Format
7. 4.7 Literal Constants
8. 4.8 Assembler Symbols
9. 4.9 Expressions
10. 4.10 Built-in Functions and Operators
  1. 4.10.1 Built-In Math and Trigonometric Functions
11. 4.11 TMS320C28x Assembler Extensions
12. 4.12 Source Listings
13. 4.13 Debugging Assembly Source
14. 4.14 Cross-Reference Listings
15. 4.15 Smart Encoding
16. 4.16 Pipeline Conflict Detection
5 Assembler Directives
1. 5.1 Directives Summary
2. 5.2 Directives that Define Sections
3. 5.3 Directives that Initialize Values
4. 5.4 Directives that Perform Alignment and Reserve Space
5. 5.5 Directives that Format the Output Listings
6. 5.6 Directives that Reference Other Files
7. 5.7 Directives that Enable Conditional Assembly
8. 5.8 Directives that Define Union or Structure Types
9. 5.9 Directives that Define Enumerated Types
10. 5.10 Directives that Define Symbols at Assembly Time
11. 5.11 Miscellaneous Directives
12. 5.12 Directives Reference
  1. .align
  2. .asg/.define/.eval
  3. .asmfunc/.endasmfunc
  4. .bits
  5. .bss
  6. .byte/.ubyte/.char/.uchar
  7. .cdecls
  8. .clink
  9. .common
  10. .copy/.include
  11. .cstruct/.cunion/.endstruct/.endunion/.tag
  12. .data
  13. .drlist/.drnolist
  14. .elfsym
  15. .emsg/.mmsg/.wmsg
  16. .end
  17. .fclist/.fcnolist
  18. .field
  19. .float/.xfloat/.xldouble
  20. .global/.def/.ref
  21. .group/.gmember/.endgroup
  22. .if/.elseif/.else/.endif
  23. .int/.unint/.word/.uword
  24. .label
  25. .length/.width
  26. .list/.nolist
  27. .long/.ulong/.xlong
  28. .loop/.endloop/.break
  29. .macro/.endm
  30. .mlib
  31. .mlist/.mnolist
  32. .newblock
  33. .option
  34. .page
  35. .preserve
  36. .retain / .retainrefs
  37. .sblock
  38. .sect
  39. .set
  40. .space/.bes
  41. .sslist/.ssnolist
  42. .string/.cstring/.pstring
  43. .struct/.endstruct/.tag
  44. .symdepend
  45. .tab
  46. .text
  47. .title
  48. .unasg/.undefine
  49. .union/.endunion/.tag
  50. .usect
  51. .var
  52. .weak
6 Macro Language Description
1. 6.1 Using Macros
2. 6.2 Defining Macros
3. 6.3 Macro Parameters/Substitution Symbols
4. 6.4 Macro Libraries
5. 6.5 Using Conditional Assembly in Macros
6. 6.6 Using Labels in Macros
7. 6.7 Producing Messages in Macros
8. 6.8 Using Directives to Format the Output Listing
9. 6.9 Using Recursive and Nested Macros
10. 6.10 Macro Directives Summary
7 Archiver Description
1. 7.1 Archiver Overview
2. 7.2 The Archiver's Role in the Software Development Flow
3. 7.3 Invoking the Archiver
4. 7.4 Archiver Examples
5. 7.5 Library Information Archiver Description
8 Linker Description
1. 8.1 Linker Overview
2. 8.2 The Linker's Role in the Software Development Flow
3. 8.3 Invoking the Linker
4. 8.4 Linker Options
5. 8.5 Linker Command Files
6. 8.6 Linker Symbols
7. 8.7 Default Placement Algorithm
  1. 8.7.1 How the Allocation Algorithm Creates Output Sections
  2. 8.7.2 Reducing Memory Fragmentation
8. 8.8 Using Linker-Generated Copy Tables
9. 8.9 Linker-Generated CRC Tables and CRC Over Memory Ranges
10. 8.10 Partial (Incremental) Linking
11. 8.11 Linking C/C++ Code
12. 8.12 Linker Example
9 Absolute Lister Description
1. 9.1 Producing an Absolute Listing
2. 9.2 Invoking the Absolute Lister
3. 9.3 Absolute Lister Example
10Cross-Reference Lister Description
1. 10.1 Producing a Cross-Reference Listing
2. 10.2 Invoking the Cross-Reference Lister
3. 10.3 Cross-Reference Listing Example
11Object File Utilities
1. 11.1 Invoking the Object File Display Utility
2. 11.2 Invoking the Disassembler
3. 11.3 Invoking the Name Utility
4. 11.4 Invoking the Strip Utility
12Hex Conversion Utility Description
1. 12.1 The Hex Conversion Utility's Role in the Software Development Flow
2. 12.2 Invoking the Hex Conversion Utility
  1. 12.2.1 Invoking the Hex Conversion Utility From the Command Line
  2. 12.2.2 Invoking the Hex Conversion Utility With a Command File
3. 12.3 Understanding Memory Widths
4. 12.4 The ROMS Directive
  1. 12.4.1 When to Use the ROMS Directive
  2. 12.4.2 An Example of the ROMS Directive
5. 12.5 The SECTIONS Directive
6. 12.6 The Load Image Format (--load_image Option)
  1. 12.6.1 Load Image Section Formation
  2. 12.6.2 Load Image Characteristics
7. 12.7 Excluding a Specified Section
8. 12.8 Assigning Output Filenames
9. 12.9 Image Mode and the --fill Option
10. 12.10 Array Output Format
11. 12.11 Building a Table for an On-Chip Boot Loader
12. 12.12 Using Secure Flash Boot on TMS320F2838x Devices
13. 12.13 Controlling the ROM Device Address
14. 12.14 Control Hex Conversion Utility Diagnostics
15. 12.15 Description of the Object Formats
16. 12.16 Hex Conversion Utility Error Messages
13Sharing C/C++ Header Files With Assembly Source
1. 13.1 Overview of the .cdecls Directive
2. 13.2 Notes on C/C++ Conversions
3. 13.3 Notes on C++ Specific Conversions
4. 13.4 Special Assembler Support
A Symbolic Debugging Directives
1. A.1 DWARF Debugging Format
2. A.2 Debug Directive Syntax
B XML Link Information File Description
1. B.1 XML Information File Element Types
2. B.2 Document Elements
  1. B.2.1 Header Elements
  2. B.2.2 Input File List
  3. B.2.3 Object Component List
  4. B.2.4 Logical Group List
  5. B.2.5 Placement Map
  6. B.2.6 Symbol Table
C CRC Reference Implementation
1. C.1 Compilation Instructions
2. C.2 Reference CRC Calculation Routine
  1. C.2.1 Reference Implementation of a CRC Calculation Function: ref_crc.c
3. C.3 Linker-Generated Copy Tables and CRC Tables
  1. C.3.1 Main Routine for Example Application: main.c
  2. C.3.2 Checking CRC Values: check_crc.c
  3. C.3.3 Task1 Routine: task1.c
  4. C.3.4 Task2 Routine: task2.c
  5. C.3.5 Task3 Routine: task3.c
  6. C.3.6 Example 1 Command File: ex1.cmd (for COFF)
D Glossary
1. D.1 Terminology
E Revision History
499
500
501
502
E Earlier Revisions

3.1.1 Load and Run Addresses

Consider an embedded device for which the program's load image is burned onto EPROM/ROM. Variable data in the program must be writable, and so must be located in writable memory, typically RAM. However, RAM is volatile, meaning it will lose its contents when the power goes out. If this data must have an initial value, that initial value must be stored somewhere else in the load image, or it would be lost when power is cycled. The initial value must be copied from the non-volatile ROM to its run-time location in RAM before it is used. See Section 9.9 for ways this is done.

The load address is the location of an object in the load image.

The run address is the location of the object as it exists during program execution.

An object is a chunk of memory. It represents a section, segment, function, or data.

The load and run addresses for an object may be the same. This is commonly the case for program code and read-only data, such as the .econst section. In this case, the program can read the data directly from the load address. Sections that have no initial value, such as the .ebss section, do not have load data and are considered to have load and run addresses that are the same. If you specify different load and run addresses for an uninitialized section, the linker provides a warning and ignores the load address.

The load and run addresses for an object may be different. This is commonly the case for writable data, such as the .data section. The .data section's starting contents are placed in ROM and copied to RAM. This often occurs during program startup, but depending on the needs of the object, it may be deferred to sometime later in the program as described in Section 4.6.

Symbols in assembly code and object files almost always refer to the run address. When you look at an address in the program, you are almost always looking at the run address. The load address is rarely used for anything but initialization.

The load and run addresses for a section are controlled by the linker command file and are recorded in the object file metadata.

The load address determines where a loader places the raw data for the section. Any references to the section (such as references to labels in it) refer to its run address. The application must copy the section from its load address to its run address before the first reference of the symbol is encountered at run time; this does not happen automatically simply because you specify a separate run address. For examples that specify load and run addresses, see Section 9.6.6.1.

For an example that illustrates how to move a block of code at run time, see Moving a Function from Slow to Fast Memory at Run Time. To create a symbol that lets you refer to the load-time address, rather than the run-time address, see the .label directive. To use copy tables to copy objects from load-space to run-space at boot time, see Section 9.9.

ELF format executable object files contain segments. See Section 3.4 for information about sections and segments. COFF format executable object files contain sections.