BL51: LOCATING CONSTANT (CODE) VARIABLES IN A CODE BANK

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Information in this article applies to:

• C51 Version 5.50a
• C51 Version 6.01

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QUESTION

How do I locate a constant variable in a code bank? I have a source file with a table declared as follows:

unsigned char const code table [10] = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j' };

When I compile and link, the functions in this source file are located in the correct bank, but the table is located in the common area.

ANSWER

When you compile a source file (for example MYCODE.C), the compiler creates program segments for your functions and code segments for your code-based variables.

Each function will be located in a segment named ?PR?function_name?source_file_name.

All code variables will be located in a segment named ?CO?source_file_name.

The linker has commands that let you automatically locate all of the program code from a source file in a code bank. However, the code segments from that file are NOT located in the code bank. You must do that manually.

To locate the code variables in a particular bank, link using a similar command line:

bl51 ... bankarea (0x8000,0xFFFF) BANK0(?CO?MYCODE (0x8000)) ...

or

bl51 ... bankarea (0x8000,0xFFFF) BANK0(0x8000, ?CO?MYCODE) ...

If you use the µVision IDE, enter the following in the Misc Controls input box in the L51 Misc dialog box.

BANK0(?CO?MYCODE (0x8000))

This locates the code variables from MYCODE.C in BANK0.

MORE INFORMATION

• Refer to BANKx in the BL51 User's Guide.

SEE ALSO

• C51: CREATING CODE BANKING PROGRAMS
• BL51: USING FUNCTION POINTERS WITH CODE BANKING
• C51: INDIRECT FUNCTION CALLS WITH CODE BANKING
• C51: CALCULATING CODE SPACE FOR BANK SWITCHING
• µVision1: SPECIFYING CODE BANKS FOR BANK SWITCHING
• BL51: THE CODE BANKING MECHANISM

FORUM THREADS

The following Discussion Forum threads may provide information related to this topic.

• C51:Code banking string problem
• locating code constants in bank1
• how to easily locate constant in bank easily?

Last Reviewed: Friday, July 15, 2005

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