Routines
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34499: Display the code entry screen
Used by the routine at 34463. Displays the code entry screen and waits for a code to be entered. Returns with the zero flag set if the code entered is correct.
Input
IX Address of the message to print (34187 or 34219)
34499 LD DE,18432 Print the message pointed to by IX at (8,0)
34502 LD C,32
34504 CALL 38528
34507 LD HL,18498 Print the graphic for the '1' key at (10,2)
34510 LD DE,39680
34513 LD C,0
34515 CALL 37974
34518 LD HL,18501 Print the graphic for the '2' key at (10,5)
34521 CALL 37974
34524 LD HL,18504 Print the graphic for the '3' key at (10,8)
34527 CALL 37974
34530 LD HL,18507 Print the graphic for the '4' key at (10,11)
34533 CALL 37974
34536 LD HL,39808 Copy the 128 attribute bytes from 39808 to the screen (lines 8, 9, 10 and 11)
34539 LD DE,22784
34542 LD BC,128
34545 LDIR
34547 LD A,(23672) Collect the LSB of the system variable FRAMES
34550 ADD A,37 Add 37 to this value and replace it; this ensures that the value collected on the second pass through this routine is different from the value collected on the first pass
34552 LD (23672),A
34555 CP 179 Is the value between 0 and 178?
34557 JR C,34561 Jump if so
34559 SUB 180 Otherwise subtract 180; note that if the original value of the LSB of the system variable FRAMES was 142, this leaves A holding 255, which is a bug
34561 LD L,A Now L holds either 255 or some number between 0 and 178
34562 LD H,158 Point HL at one of the entries in the table at 40448 (or at 40703 if L=255)
34564 LD A,(HL) Pick up the table entry
34565 ADD A,L Add L to obtain the actual code
34566 LD (34276),A Store the code at 34276
34569 LD C,L Copy the code index to C; this will be used to compute the grid location
34570 LD E,47 Calculate the ASCII code of the grid location number (0-9) in E
34572 INC E
34573 LD A,C
34574 CP 18
34576 JR C,34583
34578 SUB 18
34580 LD C,A
34581 JR 34572
34583 LD A,E Print the grid location number at (8,30)
34584 LD DE,18462
34587 CALL 38545
34590 LD A,C Calculate the ASCII code of the grid location letter (A-R) in A
34591 ADD A,65
34593 LD DE,18461 Print the grid location letter at (8,29)
34596 CALL 38545
Here we enter a loop that prints a 2x2 coloured block at (10,16), (10,19), (10,22) or (10,25) whenever '1', '2', '3' or '4' is pressed, or returns to the calling routine at 34463 if ENTER is pressed.
34599 LD IX,22864 Point IX at the attribute file location of the first coloured block at (10,16)
34603 CALL 34620 Print a coloured block when '1', '2', '3' or '4' is pressed, or return to 34463 if ENTER is pressed
34606 INC IX Move IX along to the location of the next coloured block
34608 INC IX
34610 INC IX
34612 LD A,IXl Have we just printed the fourth coloured block at (10,25)?
34614 CP 92
34616 JR NZ,34603 If not, jump back to print the next one
34618 JR 34599 Otherwise rewind IX to the location of the first coloured block
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