CALL	24FB,SCANNING	The string is treated as a 'next
				expression' and a 'last value'
				produced.
		POP	HL	The original value of CH-ADD is
		LD	(CH-ADD),HL	restored.
		JR	35BF,STK-PNTRS	The subroutine exits via STK-
				PNTRS which resets the pointers.

THE 'STR$' FUNCTION
(Offset 2E: 'str$')

This subroutine handles the function STR$ X and returns a 'last value' which is a set of parameters that define a string containing what would appear on the screen if X were displayed by a PRINT command.

361F	str$	LD	BC,+0001	One space is made in the work
		RST	0030,BC-SPACES	space and its address is copied
		LD	(K-CUR),HL	to K-CUR, the address of the
				cursor.
		PUSH	HL	This address is saved on the
				stack too.
		LD	HL,(CURCHL)	The current channel address is
		PUSH	HL	saved on the machine stack.
		LD	A,+FF	Channel 'R' is opened, allowing
		CALL	1601,CHAN-OPEN	the string to be 'printed' out
				into the work space.
		CALL	2DE3,PRINT-FP	The 'last value', X, is now
				printed out in the work space
				amd the work space is expanded
				with each character.
		POP	HL	Restore CURCHL to HL and
		CALL	1615,CHAN-FLAG	restore the flags that are
				appropriate to it.
		POP	DE	Restore the start address of the
				string.
		LD	HL,(K-CUR)	Now the cursor address is one
		AND	A	past the end of the string and
		SBC	HL,DE	hence the difference is the
				length.
		LD	B,H	Transfer the length to BC.
		LD	C,L	
		CALL	2AB2,STK-STO-$	Pass the parameters of the new
				string to the calculator stack.
		EX	DE,HL	Reset the pointers.
		RET		Finished.

Note: See PRINT-FP for an explanation of the 'PRINT "A"+STR$ 0.1' error.

THE 'READ-IN' SUBROUTINE
(Offset 1A: 'read-in')

This subroutine is called via the calculator offset through the first line of the S-INKEY$ routine in SCANNING. It appears to provide for the reading in of data through different streams from those available on the standard Spectrum. Like INKEY$ the subroutine returns a string.

3654	read-in	CALL	1E94,FIND-INT1	The numerical parameter is
				compressed into the A register.
		CP	+10	Is it smaller than 16 decimal?
		JP	NC,1E9F,REPORT-B	If not , report the error.
		LD	HL,(CURCHL)	The current channel address is
		PUSH	HL	saved on the machine stack.
		CALL	1601,CHAN-OPEN	The channel specified by the
				parameter is opened.