SPRAC71B February   2019  – October 2023

 

  1.   1
  2. 1 Introduction
    1. 1.1  ABIs for the C28x
    2. 1.2  Scope
    3. 1.3  ABI Variants
    4. 1.4  Toolchains and Interoperability
    5. 1.5  Libraries
    6. 1.6  Types of Object Files
    7. 1.7  Segments
    8. 1.8  C28x Architecture Overview
    9. 1.9  C28x Memory Models
    10. 1.10 Reference Documents
    11. 1.11 Code Fragment Notation
  3. 2 Data Representation
    1. 2.1 Basic Types
    2. 2.2 Data in Registers
    3. 2.3 Data in Memory
    4. 2.4 Pointer Types
    5. 2.5 Complex Types
    6. 2.6 Structures and Unions
    7. 2.7 Arrays
    8. 2.8 Bit Fields
      1. 2.8.1 Volatile Bit Fields
    9. 2.9 Enumeration Types
  4. 3 Calling Conventions
    1. 3.1 Call and Return
      1. 3.1.1 Call Instructions
        1. 3.1.1.1 Indirect Calls
        2. 3.1.1.2 Direct Calls
      2. 3.1.2 Return Instruction
      3. 3.1.3 Pipeline Conventions
      4. 3.1.4 Weak Functions
    2. 3.2 Register Conventions
      1. 3.2.1 Argument Registers
      2. 3.2.2 Callee-Saved Registers
    3. 3.3 Argument Passing
      1. 3.3.1 Passing 16-Bit Arguments
      2. 3.3.2 Passing Longer Arguments
      3. 3.3.3 C++ Argument Passing
      4. 3.3.4 Passing Structs and Unions
      5. 3.3.5 Stack Layout of Arguments Not Passed in Registers
      6. 3.3.6 Frame Pointer
    4. 3.4 Return Values
    5. 3.5 Structures and Unions Passed and Returned by Reference
    6. 3.6 Conventions for Compiler Helper Functions
    7. 3.7 Prolog and Epilog Helper Functions
    8. 3.8 Scratch Registers for Functions Already Seen
    9. 3.9 Interrupt Functions
  5. 4 Data Allocation and Addressing
    1. 4.1 Data Sections and Segments
    2. 4.2 Data Blocking
    3. 4.3 Addressing Modes
    4. 4.4 Allocation and Addressing of Static Data
      1. 4.4.1 Addressing Methods for Static Data
      2. 4.4.2 Placement Conventions for Static Data
        1. 4.4.2.1 Abstract Conventions for Addressing
      3. 4.4.3 Initialization of Static Data
    5. 4.5 Automatic Variables
    6. 4.6 Frame Layout
      1. 4.6.1 Stack Alignment
      2. 4.6.2 Register Save Order
    7. 4.7 Heap-Allocated Objects
  6. 5 Code Allocation and Addressing
    1. 5.1 Computing the Address of a Code Label
    2. 5.2 Calls
      1. 5.2.1 Direct Call
      2. 5.2.2 Far Call Trampoline
      3. 5.2.3 Indirect Calls
  7. 6 Helper Function API
    1. 6.1 Floating-Point Behavior
    2. 6.2 C Helper Function API
    3. 6.3 Floating-Point Helper Functions for C99
  8. 7 Standard C Library API
    1. 7.1  About Standard C Libraries
    2. 7.2  Reserved Symbols
    3. 7.3  <assert.h> Implementation
    4. 7.4  <complex.h> Implementation
    5. 7.5  <ctype.h> Implementation
    6. 7.6  <errno.h> Implementation
    7. 7.7  <float.h> Implementation
    8. 7.8  <inttypes.h> Implementation
    9. 7.9  <iso646.h> Implementation
    10. 7.10 <limits.h> Implementation
    11. 7.11 <locale.h> Implementation
    12. 7.12 <math.h> Implementation
    13. 7.13 <setjmp.h> Implementation
    14. 7.14 <signal.h> Implementation
    15. 7.15 <stdarg.h> Implementation
    16. 7.16 <stdbool.h> Implementation
    17. 7.17 <stddef.h> Implementation
    18. 7.18 <stdint.h> Implementation
    19. 7.19 <stdio.h> Implementation
    20. 7.20 <stdlib.h> Implementation
    21. 7.21 <string.h> Implementation
    22. 7.22 <tgmath.h> Implementation
    23. 7.23 <time.h> Implementation
    24. 7.24 <wchar.h> Implementation
    25. 7.25 <wctype.h> Implementation
  9. 8 C++ ABI
    1. 8.1  Limits (GC++ABI 1.2)
    2. 8.2  Export Template (GC++ABI 1.4.2)
    3. 8.3  Data Layout (GC++ABI Chapter 2)
    4. 8.4  Initialization Guard Variables (GC++ABI 2.8)
    5. 8.5  Constructor Return Value (GC++ABI 3.1.5)
    6. 8.6  One-Time Construction API (GC++ABI 3.3.2)
    7. 8.7  Controlling Object Construction Order (GC++ ABI 3.3.4)
    8. 8.8  Demangler API (GC++ABI 3.4)
    9. 8.9  Static Data (GC++ ABI 5.2.2)
    10. 8.10 Virtual Tables and the Key function (GC++ABI 5.2.3)
    11. 8.11 Unwind Table Location (GC++ABI 5.3)
  10. 9 Exception Handling
    1. 9.1  Overview
    2. 9.2  PREL31 Encoding
    3. 9.3  The Exception Index Table (EXIDX)
      1. 9.3.1 Pointer to Out-of-Line EXTAB Entry
      2. 9.3.2 EXIDX_CANTUNWIND
      3. 9.3.3 Inlined EXTAB Entry
    4. 9.4  The Exception Handling Instruction Table (EXTAB)
      1. 9.4.1 EXTAB Generic Model
      2. 9.4.2 EXTAB Compact Model
      3. 9.4.3 Personality Routines
    5. 9.5  Unwinding Instructions
      1. 9.5.1 Common Sequence
      2. 9.5.2 Byte-Encoded Unwinding Instructions
    6. 9.6  Descriptors
      1. 9.6.1 Encoding of Type Identifiers
      2. 9.6.2 Scope
      3. 9.6.3 Cleanup Descriptor
      4. 9.6.4 Catch Descriptor
      5. 9.6.5 Function Exception Specification (FESPEC) Descriptor
    7. 9.7  Special Sections
    8. 9.8  Interaction With Non-C++ Code
      1. 9.8.1 Automatic EXIDX Entry Generation
      2. 9.8.2 Hand-Coded Assembly Functions
    9. 9.9  Interaction With System Features
      1. 9.9.1 Shared Libraries
      2. 9.9.2 Overlays
      3. 9.9.3 Interrupts
    10. 9.10 Assembly Language Operators in the TI Toolchain
  11. 10DWARF
    1. 10.1 DWARF Register Names
    2. 10.2 Call Frame Information
    3. 10.3 Vendor Names
    4. 10.4 Vendor Extensions
  12. 11ELF Object Files (Processor Supplement)
    1. 11.1 Registered Vendor Names
    2. 11.2 ELF Header
    3. 11.3 Sections
      1. 11.3.1 Section Indexes
      2. 11.3.2 Section Types
      3. 11.3.3 Extended Section Header Attributes
      4. 11.3.4 Subsections
      5. 11.3.5 Special Sections
      6. 11.3.6 Section Alignment
    4. 11.4 Symbol Table
      1. 11.4.1 Symbol Types
      2. 11.4.2 Common Block Symbols
      3. 11.4.3 Symbol Names
      4. 11.4.4 Reserved Symbol Names
      5. 11.4.5 Mapping Symbols
    5. 11.5 Relocation
      1. 11.5.1 Relocation Types
        1. 11.5.1.1 Absolute Relocations
        2. 11.5.1.2 PC-Relative Relocations
        3. 11.5.1.3 Relocations in Data Sections
        4. 11.5.1.4 Relocations for C28x Instructions
        5. 11.5.1.5 Other Relocation Types
      2. 11.5.2 Relocation Operations
      3. 11.5.3 Relocation of Unresolved Weak References
  13. 12ELF Program Loading and Linking (Processor Supplement)
    1. 12.1 Program Header
      1. 12.1.1 Base Address
      2. 12.1.2 Segment Contents
      3. 12.1.3 Thread-Local Storage
    2. 12.2 Program Loading
  14. 13Build Attributes
    1. 13.1 About Build Attributes
    2. 13.2 C28x ABI Build Attribute Subsection
    3. 13.3 Build Attribute Tags
  15. 14Copy Tables and Variable Initialization
    1. 14.1 About Copy Tables
    2. 14.2 Copy Table Format
    3. 14.3 Compressed Data Formats
      1. 14.3.1 RLE
      2. 14.3.2 LZSS Format
    4. 14.4 Variable Initialization
  16. 15Revision History
    1.     188

11.5.1 Relocation Types

Relocation types are described in two tables. Table 11-5 gives numeric values for the relocation types and summarizes the computation of the relocated value. Following that table is a description of the relocation types and examples of their use. Table 11-6 describes, for each type, the exact computation, including extraction and insertion of the relocation field, overflow checking, and any scaling or other adjustments.

The following notations are used in Table 11-5.

SThe value of the symbol associated with the relocation, specified by the symbol table index contained in the r_info field in the relocation entry.
AThe addend used to compute the value of the relocatable field. For Elf32_rel relocations, A is encoded into the relocatable field according to Table 11-6. For Elf32_Rela relocations, A is given by the r_addend field of the relocation entry.
PCThe address of the container containing the field. This may not be the same as the address of the instruction containing the relocation.
Table 11-5 C28x Relocation Types
NameValueOperationConstraints
R_C28X_NONE0
R_C28X_ABS81S + A
R_C28X_ABS162S + A
R_C28X_ABS323S + A
R_C28X_ABSLO64S+A
R_C28X_ABSLO6_BLKD4S+ADuplicate, but indicates blocked access
R_C28X_ABS225S+A
R_C28X_ABS22_BR5S+ADuplicate, but used in function calls only
R_C28X_HI66S+ARela only
R_C28X_DP_HI107S+A-PCRela only
R_C28X_DP_HI168S+A
R_C28X_PCREL169S+A-PC
R_C28X_PCREL810S+A-PC
R_C28X_HI1611S+ARela only
R_C28X_NEGWORD12special
R_C28X_NEGBYTE13special
R_C28X_ABS8_HI14
R_C28X_ABS13_SE1615special
R_CLA_ABS1616S+A
R_C28X_ABSLO717S+A
R_C28X_PREL3118S+A-PC