Common use of Activation Record Clause in Contracts

Activation Record. An activation record is where a C subroutine stores its local data, saved registers and return address, etc. A typical DSP563CCC activation record consists of the following elements and is illustrated in Figure 4-2 1. Parameter data space. Information passed to C subroutines is stored in a parameter data space which is similar to the local data space (see Figure 4-2). However, the data is in reverse order and each parameter is referenced via a negative offset from the stack pointer. Actual parameters are pushed onto the activation record in reverse order by the calling subroutine. 2. Return address — which is pushed on the DSP’s system stack high (ssh) register. This is the return address to the calling subroutine. The return Program Area 3. address is not saved for subroutines that have been determined to be a leaf. A leaf subroutine is one that makes no subroutine calls. 4. Local data space. The location of C variables that have a lifetime that extends only as long as the subroutine is active and that could not be explicitly promoted to register storage class by the optimizer. 5. Register spill and compiler temporary space. This area is utilized by the compiler to store intermediate results and preserve registers.