Spectrum ROM: Routine at 2089

The address of this routine is found in the parameter table.

This routine allows for values entered from the keyboard to be assigned to variables. It is also possible to have print items embedded in the INPUT statement and these items are printed in the lower part of the display.

The address of this routine is found in the parameter table. This routine allows for values entered from the keyboard to be assigned to variables. It is also possible to have print items embedded in the INPUT statement and these items are printed in the lower part of the display.
INPUT	2089	CALL SYNTAX_Z	Jump forward if syntax is being checked.
	208C	JR Z,INPUT_1	Jump forward if syntax is being checked.
	208E	LD A,$01	Open channel 'K'.
	2090	CALL CHAN_OPEN	Open channel 'K'.
	2093	CALL CLS_LOWER	The lower part of the display is cleared.
INPUT_1	2096	LD (IY+$02),$01	Signal that the lower screen is being handled (set bit 0 of TV-FLAG and reset all other bits).
	209A	CALL IN_ITEM_1	Call the subroutine to deal with the INPUT items.
	209D	CALL CHECK_END	Move on to the next statement if checking syntax.
	20A0	LD BC,($5C88)	Fetch the current print position (S-POSN).
	20A4	LD A,($5C6B)	Jump forward if the current position is above the lower screen (see DF-SZ).
	20A7	CP B
	20A8	JR C,INPUT_2
	20AA	LD C,$21	Otherwise set the print position to the top of the lower screen.
	20AC	LD B,A
INPUT_2	20AD	LD ($5C88),BC	Reset S-POSN.
	20B1	LD A,$19	Now set the scroll counter (SCR-CT).
	20B3	SUB B
	20B4	LD ($5C8C),A
	20B7	RES 0,(IY+$02)	Signal 'main screen' (reset bit 0 of TV-FLAG).
	20BB	CALL CL_SET	Set the system variables and exit via CLS_LOWER.
	20BE	JP CLS_LOWER	Set the system variables and exit via CLS_LOWER.
The INPUT items and embedded PRINT items are dealt with in turn by the following loop.
IN_ITEM_1	20C1	CALL PR_POSN_1	Consider first any position control characters.
	20C4	JR Z,IN_ITEM_1	Consider first any position control characters.
	20C6	CP "("	Jump forward if the present character is not a '('.
	20C8	JR NZ,IN_ITEM_2	Jump forward if the present character is not a '('.
	20CA	RST $20	Fetch the next character.
	20CB	CALL PRINT_2	Now call the PRINT command routine to handle the items inside the brackets.
	20CE	RST $18	Fetch the present character.
	20CF	CP ")"	Give report C unless the character is a ')'.
	20D1	JP NZ,REPORT_C	Give report C unless the character is a ')'.
	20D4	RST $20	Fetch the next character and jump forward to see if there are any further INPUT items.
	20D5	JP IN_NEXT_2
Now consider whether INPUT LINE is being used.
IN_ITEM_2	20D8	CP $CA	Jump forward if it is not 'LINE'.
	20DA	JR NZ,IN_ITEM_3	Jump forward if it is not 'LINE'.
	20DC	RST $20	Advance CH-ADD.
	20DD	CALL CLASS_01	Determine the destination address for the variable.
	20E0	SET 7,(IY+$37)	Signal 'using INPUT LINE' (set bit 7 of FLAGX).
	20E4	BIT 6,(IY+$01)	Give report C unless using a string variable (bit 6 of FLAGS reset).
	20E8	JP NZ,REPORT_C
	20EB	JR IN_PROMPT	Jump forward to issue the prompt message.
Proceed to handle simple INPUT variables.
IN_ITEM_3	20ED	CALL ALPHA	Jump to consider going round the loop again if the present character is not a letter.
	20F0	JP NC,IN_NEXT_1
	20F3	CALL CLASS_01	Determine the destination address for the variable.
	20F6	RES 7,(IY+$37)	Signal 'not INPUT LINE' (reset bit 7 of FLAGX).
The prompt message is now built up in the work space.
IN_PROMPT	20FA	CALL SYNTAX_Z	Jump forward if only checking syntax.
	20FD	JP Z,IN_NEXT_2	Jump forward if only checking syntax.
	2100	CALL SET_WORK	The work space is set to null.
	2103	LD HL,$5C71	This is FLAGX.
	2106	RES 6,(HL)	Signal 'string result'.
	2108	SET 5,(HL)	Signal 'INPUT mode'.
	210A	LD BC,$0001	Allow the prompt message only a single location.
	210D	BIT 7,(HL)	Jump forward if using 'LINE'.
	210F	JR NZ,IN_PR_2	Jump forward if using 'LINE'.
	2111	LD A,($5C3B)	Jump forward if awaiting a numeric entry (bit 6 of FLAGS set).
	2114	AND $40
	2116	JR NZ,IN_PR_1
	2118	LD C,$03	A string entry will need three locations.
IN_PR_1	211A	OR (HL)	Bit 6 of FLAGX will become set for a numeric entry.
	211B	LD (HL),A	Bit 6 of FLAGX will become set for a numeric entry.
IN_PR_2	211C	RST $30	The required number of locations is made available.
	211D	LD (HL),$0D	A 'carriage return' goes into the last location.
	211F	LD A,C	Test bit 6 of the C register and jump forward if only one location was required.
	2120	RRCA
	2121	RRCA
	2122	JR NC,IN_PR_3
	2124	LD A,"\""	A 'double quotes' character goes into the first and second locations.
	2126	LD (DE),A
	2127	DEC HL
	2128	LD (HL),A
IN_PR_3	2129	LD ($5C5B),HL	The position of the cursor (K-CUR) can now be saved.
In the case of INPUT LINE the EDITOR can be called without further preparation but for other types of INPUT the error stack has to be changed so as to trap errors.
	212C	BIT 7,(IY+$37)	Jump forward with 'INPUT LINE' (bit 7 of FLAGX set).
	2130	JR NZ,IN_VAR_3	Jump forward with 'INPUT LINE' (bit 7 of FLAGX set).
	2132	LD HL,($5C5D)	Save the current values of CH-ADD and ERR-SP on the machine stack.
	2135	PUSH HL
	2136	LD HL,($5C3D)
	2139	PUSH HL
IN_VAR_1	213A	LD HL,$213A	This will be the 'return point' in case of errors.
	213D	PUSH HL	This will be the 'return point' in case of errors.
	213E	BIT 4,(IY+$30)	Only change the error stack pointer (ERR-SP) if using channel 'K' (bit 4 of FLAGS2 set).
	2142	JR Z,IN_VAR_2
	2144	LD ($5C3D),SP
IN_VAR_2	2148	LD HL,($5C61)	Set HL to the start of the INPUT line (WORKSP) and remove any floating-point forms. (There will not be any except perhaps after an error.)
	214B	CALL REMOVE_FP
	214E	LD (IY+$00),$FF	Signal 'no error yet' by resetting ERR-NR.
	2152	CALL EDITOR	Now get the INPUT and with the syntax/run flag (bit 7 of FLAGS) indicating syntax, check the INPUT for errors; jump if in order; return to IN_VAR_1 if not.
	2155	RES 7,(IY+$01)
	2159	CALL IN_ASSIGN
	215C	JR IN_VAR_4
IN_VAR_3	215E	CALL EDITOR	Get a 'LINE'.
All the system variables have to be reset before the actual assignment of a value can be made.
IN_VAR_4	2161	LD (IY+$22),$00	The cursor address (K-CUR) is reset.
	2165	CALL IN_CHAN_K	The jump is taken if using other than channel 'K'.
	2168	JR NZ,IN_VAR_5	The jump is taken if using other than channel 'K'.
	216A	CALL ED_COPY	The input-line is copied to the display and the position in ECHO-E made the current position in the lower screen.
	216D	LD BC,($5C82)
	2171	CALL CL_SET
IN_VAR_5	2174	LD HL,$5C71	This is FLAGX.
	2177	RES 5,(HL)	Signal 'edit mode'.
	2179	BIT 7,(HL)	Jump forward if handling an INPUT LINE.
	217B	RES 7,(HL)
	217D	JR NZ,IN_VAR_6
	217F	POP HL	Drop the address IN-VAR-1.
	2180	POP HL	Reset the ERR-SP to its original address.
	2181	LD ($5C3D),HL	Reset the ERR-SP to its original address.
	2184	POP HL	Save the original CH-ADD address in X-PTR.
	2185	LD ($5C5F),HL	Save the original CH-ADD address in X-PTR.
	2188	SET 7,(IY+$01)	Now with the syntax/run flag (bit 7 of FLAGS) indicating 'run' make the assignment.
	218C	CALL IN_ASSIGN
	218F	LD HL,($5C5F)	Restore the original address to CH-ADD and clear X-PTR.
	2192	LD (IY+$26),$00
	2196	LD ($5C5D),HL
	2199	JR IN_NEXT_2	Jump forward to see if there are further INPUT items.
IN_VAR_6	219B	LD HL,($5C63)	The length of the 'LINE' in the work space is found (STKBOT-WORKSP-1).
	219E	LD DE,($5C61)
	21A2	SCF
	21A3	SBC HL,DE
	21A5	LD B,H	DE points to the start and BC holds the length.
	21A6	LD C,L	DE points to the start and BC holds the length.
	21A7	CALL STK_STO	These parameters are stacked and the actual assignment made.
	21AA	CALL LET
	21AD	JR IN_NEXT_2	Also jump forward to consider further items.
Further items in the INPUT statement are considered.
IN_NEXT_1	21AF	CALL PR_ITEM_1	Handle any print items.
IN_NEXT_2	21B2	CALL PR_POSN_1	Handle any position controllers.
	21B5	JP Z,IN_ITEM_1	Go around the loop again if there are further items; otherwise return.
	21B8	RET