Procedure Calls

S call id ( Elist )

Elist Elist , E

Elist E

. Calling sequence

- allocate space for activation record

- evaluate arguments

- establish environment pointers

- save status and return address

- jump to the beginning of the procedure

calling sequences

. allocate space for activation record (AR) on stack

. evaluate arguments to procedure and make available at known location

. save state of calling procedure - used to resume execution after call

. save return address (in known location) (instruction following call)

. generate jump to the beginning of the called procedure

return sequence

. if a function, save the result(s) in a known place

. restore the activation record of the calling procedure

. generate a jump to the return address (of calling procedure)