SPRUJG0B December   2024  – November 2025 F29H850TU , F29H859TU-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Performance Optimization
    1. 2.1 Compiler Settings
      1. 2.1.1 Enabling Debug and Source Inter-Listing
      2. 2.1.2 Optimization Control
      3. 2.1.3 Floating-Point Math
      4. 2.1.4 Fixed-Point Division
      5. 2.1.5 Single vs Double Precision Floating-Point
      6. 2.1.6 Link-Time Optimization (LTO)
    2. 2.2 Memory Settings
      1. 2.2.1 Executing Code From RAM
      2. 2.2.2 Executing Code From Flash
      3. 2.2.3 Data Placement
    3. 2.3 Code Construction and Configuration
      1. 2.3.1 Inlining
      2. 2.3.2 Intrinsics
      3. 2.3.3 Volatile Variables
      4. 2.3.4 Function Arguments
      5. 2.3.5 Enabling Wider Data Accesses
      6. 2.3.6 Auto Code-Generation Tools
      7. 2.3.7 Accurately Profiling Code
    4. 2.4 Application Code Optimization
      1. 2.4.1 Optimized SDK Libraries
      2. 2.4.2 Optimizing Code-Size With Libraries
      3. 2.4.3 C29 Special Instructions
      4. 2.4.4 C29 Parallelism
      5. 2.4.5 32-Bit Variables and Writes Preferred
      6. 2.4.6 Coding Style and Impact on Performance
  6. 3References
  7. 4Revision History

2.4.2 Optimizing Code-Size With Libraries

Applications can include pre-compiled libraries, but can not use all the functions present in those libraries. To make sure the linker excludes unused functions in libraries and application code, make sure both are built with the below compiler option:

-ffunction-sections

Each function is then placed in a specific section, like .text.<function_name>, otherwise each function is placed in .text.

Note: Using __attribute__((section)) puts code into the corresponding section. -ffunction-sections does not affect objects with the section attribute. In such cases, if the user groups multiple functions into the same section, even if one of those functions is used, all the functions mapped to that section are linked into the final executable.