The ISPEXEC call interface allows you to specify parameters as symbolic variables. A symbolic variable is one that is preceded by an ampersand (&). Before a scan syntax check of a statement, variable names and the ampersands that precede them are replaced with the values of the corresponding variables. A single scan takes place.
Standard register conventions are used. Registers 2 to 14 are preserved across the call. However, you must use the VL keyword in Assembler call statements.