C51: Data Overlaying with RTOS applications

Information in this article applies to:

• C51 Version 7.50
• BL51 Version 5.5
• LX51 Version 3.5

QUESTION

I am a long-time user of the C51 Compiler suite for applications in a multitasking environment. The OVERLAY linker directive seems to be interpreted differently in V7.50. My application uses several tasks that run in parallel. On previous C51 versions, to keep tasks from being overlaid, I use this linker directive as follows:

OVERLAY (* ! (task1, task2, task3))

But version 7.50 overlays the data of the different tasks which results in run-time errors in my application.

How can I solve this problem?

ANSWER

The change in the behavior of the OVERLAY directive is documented in the Release-Notes file under C51 Version 7.50 Release. To get the old behavior, change the OVERLAY directive to:

OVERLAY (* ! task1, * ! task2, * ! task3)

MORE INFORMATION

• Refer to OVERLAY in the BL51 User's Guide.
• Refer to Data Overlaying in the BL51 User's Guide.

SEE ALSO

• C51: Removing Linker Warning L16 (Uncalled Segment)

Last Reviewed: Thursday, February 25, 2021