THE 'STACK FUNCTION ARGUMENT' SUBROUTINE

This subroutine is called by LOOK-VARS when DEFADD-hi in non-zero, to make a search of the arguments area of a DEF FN statement, before searching in the variables area. If the variable is found in the DEF FN statement, then the parameters of a string variable are stacked and a signal is given that there is no need to call STK/VAR. But it is left to SCANNING to stack the value of a numerical variable at 26DA in the usual way.

2951	STK-F-ARG	LD	HL,(DEFADD)	Point to the 1st character in the
		LD	A,(HL)	arguments area and put it into A.
		CP	+29	Is it a ')'?
		JP	Z.28EF,V-RUN/SYN	Jump to search the variables
				area.
295A	SFA-LOOP	LD	A,(HL)	Get the next argument in the
				loop.
		OR	+60	Set bits 5 & 6, assuming a
		LD	B,A	simple numeric variable; copy it
				to B.
		INC	HL	Point to the next code.
		LD	A,(HL)	Put it into the A register.
		CP	+0E	Is it the 'number marker' code
				0E hex?
		JR	Z,296B,SFA-CP-VR	Jump if so: numeric variable.
		DEC	HL	Ensure that HL points to the
		CALL	28AB,FN-SKPOVR	character, not to a space or
				control code.
		INC	HL	HL now points to the 'number
				marker'.
		RES	5,B	Reset bit 5 of B: string variable.
296B	SFA-CP-VR	LD	A,B	Get the variable name into A.
		CP	C	Is it the one we are looking for?
		JR	Z,2981,SFA-MATCH	Jump if it matches.
		INC	HL	Now pass over the 5 bytes of
		INC	HL	the floating-point number or
		INC	HL	string parameters to get to the
		INC	HL	next argument.
		INC	HL
		CALL	28AB,FN-SKPOVR	Pass on to the next character.
		CP	+29	Is it a ')'?
		JP	Z,28EF,V-RUN/SYN	If so, jump to search the
				variables area.
		CALL	28AB,FN-SKPOVR	Point to the next argument.
		JR	295A,SFA-LOOP	Jump back to consider it.

A match has been found. The parameters of a string variable are stacked, avoiding the need to call the STK-VAR subroutine.

2981	SFA-MATCH	BIT	5,C	Test for a numeric variable.
		JR	NZ,2991,SFA-END	Jump if the variable is numeric;
				SCANNING will stack it.
		INC	HL	Point to the first of the 5
				bytes to be stacked.
		LD	DE,(STKEND)	Point DE to STKEND.
		CALL	33C0,MOVE-FP	Stack the 5 bytes.
		EX	DE,HL	Point HL to the new position
		LD	(STKEND),HL	of STKEND, and reset the
				system variable.
2991	SFA-END	POP	DE	Discard the LOOK-VARS
		POP	DE	pointers (2nd & 1st character
				pointers).
		XOR	A	Return from the search with
		INC	A	both the carry and zero flags
				reset - signalling that a call
				STK-VAR is not required.
		RET		Finished.