.CH "Operators Useful in the Procedure Definition Stream"
.ti
.op "PROC_DEFN_OP            50"
int 50
int object_id
int number_of_args
string proc_name
tree argument_list
tree code
.bd
Each procedure to be generated by the code generator is defined by
a PROC_DEFN_OP.
The 'object_id' is an integer identifier that must be used on calls
to the procedure and other references to its entry control block
(for example, pointers to functions as used in C).
'Number_of_args' should be self-explanatory.
'Proc_name' is a string (in the IMF, a length followed by ASCII
character values) giving the internal name of the procedure.
(This information is used to print trace information during debugging.)
Each formal parameter (argument) is described by a PROC_DEFN_ARG_OP;
'argument_list' is simply a linked list of those descriptions.
'Code' is a subtree containing the body of the procedure:
local variable definitions and expressions to be evaluated.
.bx
Example:  the following C function

         main (argc, argv)
         int argc;
         char **argv;
            {
            int i;
            i = 4;
            }

         50       PROC_DEFN_OP
         1           Procedure is object number 1
         2           Procedure has 2 arguments
         4           Procedure name is 4 characters long
         237            m
         225            a
         233            i
         238            n
         49          PROC_DEFN_ARG_OP
         2              Argument is object number 2
         1              INT_MODE
         0              VAL_DISP; pass argument by value
         1              Argument is 1 word long
         49          PROC_DEFN_ARG_OP
         3              Argument is object number 3
         4              LONG_UNS_MODE (a pointer)
         1              REF_DISP; pass argument by reference
         2              Argument is 2 words long
         39          NULL_OP; end of argument description list
         59          SEQ_OP; beginning of procedure code
         13             DEFINE_DYNM_OP
         4                 Object id is 4
         39                NULL_OP; no initializers
         1                 Object is 1 word long
         59          SEQ_OP; procedure code continues
         5              ASSIGN_OP
         1                 INT_MODE
         40                OBJECT_OP
         1                    INT_MODE
         4                    Object id is 4
         9                 CONST_OP
         1                    INT_MODE
         1                    Constant is 1 word long
         4                    Constant has value 4
         1                 Assignment transfers 1 word
         39          NULL_OP; end of procedure code
.ex
.op "PROC_DEFN_ARG_OP        49"
int 49
int object_id
int mode
int disposition
int length
tree next_argument
.bd
Formal parameters to procedures are described by this operator.
The 'object_id' is an integer identifier that must be supplied on
subsequent references to the parameter (see OBJECT_OP).
The 'mode' is the machine data type of the parameter.
'Disposition' indicates how the argument is to be treated on the
call;
the two alternatives at the moment are 0 (VALUE_DISP) for pass-by-value
(aka copy in) and 1 (REF_DISP) for pass-by-reference.
'Length' gives the size of the argument in 16-bit words;
it is primarily necessary for handling of STOWED arguments that
are passed by value.
'Next_argument' is simply a link to the next PROC_DEFN_ARG_OP
in a procedure's argument descriptor list, or a NULL_OP.
.bx
See PROC_DEFN_OP for examples of PROC_DEFN_ARG_OP.
.ex
.EV
.fo //- # -//