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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 08329 CALL SYNTAX_Z Jump forward if syntax is being checked.
08332 JR Z,INPUT_1
08334 LD A,1 Open channel 'K'.
08339 CALL CLS_LOWER The lower part of the display is cleared.
INPUT_1 08342 LD (IY+2),1 Signal that the lower screen is being handled (set bit 0 of TV-FLAG and reset all other bits).
08346 CALL IN_ITEM_1 Call the subroutine to deal with the INPUT items.
08349 CALL CHECK_END Move on to the next statement if checking syntax.
08352 LD BC,(23688) Fetch the current print position (S-POSN).
08356 LD A,(23659) Jump forward if the current position is above the lower screen (see DF-SZ).
08359 CP B
08360 JR C,INPUT_2
08362 LD C,33 Otherwise set the print position to the top of the lower screen.
08364 LD B,A
INPUT_2 08365 LD (23688),BC Reset S-POSN.
08369 LD A,25 Now set the scroll counter (SCR-CT).
08371 SUB B
08372 LD (23692),A
08375 RES 0,(IY+2) Signal 'main screen' (reset bit 0 of TV-FLAG).
08379 CALL CL_SET 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 08385 CALL PR_POSN_1 Consider first any position control characters.
08388 JR Z,IN_ITEM_1
08390 CP "(" Jump forward if the present character is not a '('.
08392 JR NZ,IN_ITEM_2
08394 RST 32 Fetch the next character.
08395 CALL PRINT_2 Now call the PRINT command routine to handle the items inside the brackets.
08398 RST 24 Fetch the present character.
08399 CP ")" Give report C unless the character is a ')'.
08404 RST 32 Fetch the next character and jump forward to see if there are any further INPUT items.
08405 JP IN_NEXT_2
Now consider whether INPUT LINE is being used.
IN_ITEM_2 08408 CP 202 Jump forward if it is not 'LINE'.
08410 JR NZ,IN_ITEM_3
08412 RST 32 Advance CH-ADD.
08413 CALL CLASS_01 Determine the destination address for the variable.
08416 SET 7,(IY+55) Signal 'using INPUT LINE' (set bit 7 of FLAGX).
08420 BIT 6,(IY+1) Give report C unless using a string variable (bit 6 of FLAGS reset).
08427 JR IN_PROMPT Jump forward to issue the prompt message.
Proceed to handle simple INPUT variables.
IN_ITEM_3 08429 CALL ALPHA Jump to consider going round the loop again if the present character is not a letter.
08432 JP NC,IN_NEXT_1
08435 CALL CLASS_01 Determine the destination address for the variable.
08438 RES 7,(IY+55) Signal 'not INPUT LINE' (reset bit 7 of FLAGX).
The prompt message is now built up in the work space.
IN_PROMPT 08442 CALL SYNTAX_Z Jump forward if only checking syntax.
08445 JP Z,IN_NEXT_2
08448 CALL SET_WORK The work space is set to null.
08451 LD HL,23665 This is FLAGX.
08454 RES 6,(HL) Signal 'string result'.
08456 SET 5,(HL) Signal 'INPUT mode'.
08458 LD BC,1 Allow the prompt message only a single location.
08461 BIT 7,(HL) Jump forward if using 'LINE'.
08463 JR NZ,IN_PR_2
08465 LD A,(23611) Jump forward if awaiting a numeric entry (bit 6 of FLAGS set).
08468 AND 64
08470 JR NZ,IN_PR_1
08472 LD C,3 A string entry will need three locations.
IN_PR_1 08474 OR (HL) Bit 6 of FLAGX will become set for a numeric entry.
08475 LD (HL),A
IN_PR_2 08476 RST 48 The required number of locations is made available.
08477 LD (HL),13 A 'carriage return' goes into the last location.
08479 LD A,C Test bit 6 of the C register and jump forward if only one location was required.
08480 RRCA
08481 RRCA
08482 JR NC,IN_PR_3
08484 LD A,"\"" A 'double quotes' character goes into the first and second locations.
08486 LD (DE),A
08487 DEC HL
08488 LD (HL),A
IN_PR_3 08489 LD (23643),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.
08492 BIT 7,(IY+55) Jump forward with 'INPUT LINE' (bit 7 of FLAGX set).
08496 JR NZ,IN_VAR_3
08498 LD HL,(23645) Save the current values of CH-ADD and ERR-SP on the machine stack.
08501 PUSH HL
08502 LD HL,(23613)
08505 PUSH HL
IN_VAR_1 08506 LD HL,8506 This will be the 'return point' in case of errors.
08509 PUSH HL
08510 BIT 4,(IY+48) Only change the error stack pointer (ERR-SP) if using channel 'K' (bit 4 of FLAGS2 set).
08514 JR Z,IN_VAR_2
08516 LD (23613),SP
IN_VAR_2 08520 LD HL,(23649) 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.)
08526 LD (IY+0),255 Signal 'no error yet' by resetting ERR-NR.
08530 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.
08533 RES 7,(IY+1)
08540 JR IN_VAR_4
IN_VAR_3 08542 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 08545 LD (IY+34),0 The cursor address (K-CUR) is reset.
08549 CALL IN_CHAN_K The jump is taken if using other than channel 'K'.
08552 JR NZ,IN_VAR_5
08554 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.
08557 LD BC,(23682)
IN_VAR_5 08564 LD HL,23665 This is FLAGX.
08567 RES 5,(HL) Signal 'edit mode'.
08569 BIT 7,(HL) Jump forward if handling an INPUT LINE.
08571 RES 7,(HL)
08573 JR NZ,IN_VAR_6
08575 POP HL Drop the address IN-VAR-1.
08576 POP HL Reset the ERR-SP to its original address.
08577 LD (23613),HL
08580 POP HL Save the original CH-ADD address in X-PTR.
08581 LD (23647),HL
08584 SET 7,(IY+1) Now with the syntax/run flag (bit 7 of FLAGS) indicating 'run' make the assignment.
08591 LD HL,(23647) Restore the original address to CH-ADD and clear X-PTR.
08594 LD (IY+38),0
08598 LD (23645),HL
08601 JR IN_NEXT_2 Jump forward to see if there are further INPUT items.
IN_VAR_6 08603 LD HL,(23651) The length of the 'LINE' in the work space is found (STKBOT-WORKSP-1).
08606 LD DE,(23649)
08610 SCF
08611 SBC HL,DE
08613 LD B,H DE points to the start and BC holds the length.
08614 LD C,L
08615 CALL STK_STO These parameters are stacked and the actual assignment made.
08618 CALL LET
08621 JR IN_NEXT_2 Also jump forward to consider further items.
Further items in the INPUT statement are considered.
IN_NEXT_1 08623 CALL PR_ITEM_1 Handle any print items.
IN_NEXT_2 08626 CALL PR_POSN_1 Handle any position controllers.
08629 JP Z,IN_ITEM_1 Go around the loop again if there are further items; otherwise return.
08632 RET
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