跳至主要內容
Knowledgebase
Home
Renesas Electronics Taiwan - Knowledgebase

What is optimization of external variable access?

Latest Updated:02/27/2015

Question:

What is optimization of external variable access?

Answer:

There are two types of optimization of external variable accesses; the –Osmap option for intra-module optimization and the –Omap option for inter-module optimization.

Specifying the –Osmap option leads to the generation of code that includes ep-register-relative access to external variables which have been defined in the same file of source code (the ep register is register r30).

Specifying the –Omap option leads to the generation of code that includes ep-register-relative access to external variables which have been defined in the same file of source code as well as to any other external variable that has been defined in the program. When the external symbol-allocation information file (*.bls) is generated in a build to rebuild the information in the file, access to variables for external reference is also ep-relative access.

Suitable Products
C Compiler Package for RH850 Family