CEEVROND — run on downward-growing stack

This CWI is invoked from a non-XPLINK routine running on the upward-growing stack. It is used to invoke an XPLINK routine that runs on the downward-growing stack. It performs stack swapping, moves the parameter list, and loads appropriate parameters into registers before invoking the routine. After the routine returns, it will adjust the return value and swap the stacks back.

This CWI has two entry points: +0 for standard linkage and +16 for FASTLINK linkage.

Linkage	Input/Output	Register	Used for
Standard	Input Registers	R0	Function descriptor
		R1	Parameter List
		R2 - R11	Not used
		R12	CAA address
		R13	Caller's DSA
		R14	Return address
		R15	Entry point (CEEVROND)
	Output Registers	R0	Extended return value
		R1 - R14	Unchanged
		R15	Return value
FASTLINK	Input Registers	R0	Function descriptor
		R1 - R3	Parameters
		R4 - R11	Not used
		R12	CAA address
		R13	Caller's DSA
		R14	Return address
		R15	Entry point (CEEVROND)
		NAB + BC	Parameter list
	Output Registers	R0	Not preserved
		R1 - R3	Return value
		R4 - R14	Unchanged
		R15	Not preserved

CEEVROND

Call this CWI interface as follows:

L     15,CEECAACELV-CEECAA(,12)   Address of CAA in R12
L     15,3408(,15)
BALR  14,15

This CWI will return control to its invoker at the return address:

BR    14

Function descriptor: A 24 byte function descriptor that contains the environment and entry point for the XPLINK routine to be invoked at offset +16 ('10'x).
Parameter List: The parameter list for the routine to be invoked.

Note: CEEVROND has a stub called @@ROND.