Index Modification Writes to System Device

What does 1103 mean?

This error occurs in Basic model QCPU, High Performance model QCPU, Process CPU, and Redundant CPU when data, after being modified by an index register, attempts to write to a device reserved for system use. While device range checks aren't always conducted, writing to a system device specifically triggers this error, indicating a critical memory access violation and potential system instability.

• Program logic using indexing (e.g., X10Z0) results in an address pointing to a system-reserved device range.
• An indexed write operation bypasses standard device range checks and targets a protected system memory area.
• Improper calculation of indexed addresses leads to an unintended memory overwrite.

Click steps to track your progress.

1. 1

   Review the program logic where index registers (e.g., Z0) are used in conjunction with write instructions.

2. 2

   Carefully calculate the maximum possible address that an indexed instruction can access in a given program segment.

3. 3

   Adjust device assignments or limit the range of index registers to prevent access to system-reserved device ranges.

4. 4

   Verify the CPU type and its specific handling of device range checks during indexed operations.