Spectrum ROM: Routine at 1FFC

1FFC: THE 'PRINT ITEMS' SUBROUTINE

This subroutine is called from the PRINT_2 and INPUT routines. The various types of print item are identified and printed.
PR_ITEM_1	1FFC	RST $18	The first character is fetched.
	1FFD	CP $AC	Jump forward unless it is an 'AT'.
	1FFF	JR NZ,PR_ITEM_2	Jump forward unless it is an 'AT'.
Now deal with an 'AT'.
	2001	CALL NEXT_2NUM	The two parameters are transferred to the calculator stack.
	2004	CALL UNSTACK_Z	Return now if checking syntax.
	2007	CALL STK_TO_BC	The parameters are compressed into the BC register pair.
	200A	LD A,$16	The A register is loaded with the AT control character before the jump is taken.
	200C	JR PR_AT_TAB
Next look for a 'TAB'.
PR_ITEM_2	200E	CP $AD	Jump forward unless it is a 'TAB'.
	2010	JR NZ,PR_ITEM_3	Jump forward unless it is a 'TAB'.
Now deal with a 'TAB'.
	2012	RST $20	Get the next character.
	2013	CALL CLASS_06	Transfer one parameter to the calculator stack.
	2016	CALL UNSTACK_Z	Return now if checking syntax.
	2019	CALL FIND_INT2	The value is compressed into the BC register pair.
	201C	LD A,$17	The A register is loaded with the TAB control character.
The 'AT' and the 'TAB' print items are printed by making three calls to PRINT_A_1.
PR_AT_TAB	201E	RST $10	Print the control character.
	201F	LD A,C	Follow it with the first value.
	2020	RST $10	Follow it with the first value.
	2021	LD A,B	Finally print the second value, then return.
	2022	RST $10
	2023	RET
Next consider embedded colour items.
PR_ITEM_3	2024	CALL CO_TEMP_3	Return with carry reset if colour items were found. Continue if none were found.
	2027	RET NC
	2028	CALL STR_ALTER	Next consider if the stream is to be changed.
	202B	RET NC	Continue unless it was altered.
The print item must now be an expression, either numeric or string.
	202C	CALL SCANNING	Evaluate the expression but return now if checking syntax.
	202F	CALL UNSTACK_Z	Evaluate the expression but return now if checking syntax.
	2032	BIT 6,(IY+$01)	Test for the nature of the expression (bit 6 of FLAGS).
	2036	CALL Z,STK_FETCH	If it is a string then fetch the necessary parameters; but if it is numeric then exit via PRINT_FP.
	2039	JP NZ,PRINT_FP
A loop is now set up to deal with each character in turn of the string.
PR_STRING	203C	LD A,B	Return now if there are no characters remaining in the string; otherwise decrease the counter.
	203D	OR C
	203E	DEC BC
	203F	RET Z
	2040	LD A,(DE)	Fetch the code and increment the pointer.
	2041	INC DE	Fetch the code and increment the pointer.
	2042	RST $10	The code is printed and a jump taken to consider any further characters.
	2043	JR PR_STRING