Load, then add in assembly
The assembler in Code Composer Studio does not use the "=" to indicate a literal operand to an LDR instruction. The gnu assembler does use the "=" but I don't know about other tools.

However, you need additional directives to indicate that you are writing an ARM Thumb-2 function.

There are other problems with your code, but we'll give you time to think about those and ask a specific question.