arrow keys off routine

[Marius]

Hi!

 

Is there a way of switching the Arrow Keys off?

 

I am writing a routine with some input fields. I don't want that the user can WALK over the screen with the cursor.

 

The only thing I can think of is check ROWCRS ($54) and COLCRS ($55, $56) all the time, and reset those registers when someone walks out of the range.

 

Break can be switched off by disableng the IRQ for that.

Is there such a solution for the ARROW keys too?

 

Thanks

M.

[Rybags]

There's a few things you could do:

 

1. On the XL/XE only, the keyboard definition table can be user-provided in RAM, so you could have an alternate map without cursor movement.

 

2. DIY keyboard IRQ routine that masks out cursor keys.

 

3. Easiest way - just use K: for input instead of E:, mask out the keys you don't want, then echo input to E:

Advantage there is you could also put a limit on input field size, disadvantage is you still need to handle Backspace, and you'd need to read the input off the screen once the user presses Return.

 

Problem with 1 & 2 is with cursor keys disabled you can still get runaway conditions e.g. where the user just enters hundreds of characters worth of input, but of course E: will never return more than 3 screen lines worth of data.

[Marius]

@Rybags

 

Wow. Thanks for your feedback. That is a lot of interesting information.

 

I will think it over. Thanks a lot!

 

Greetz

M.

[Fox-1 / mnx]

Use address $02FC.

 

INPUT
LDA #$FF
STA $02FC ; Reset register
LOOP
LDA $02FC ; CH  holds last key press
CMP #$06 ; left arrow
BEQ LOOP
CMP #$07 ; right arrow
BEQ LOOP
etc...
CMP #$FF ; No key pressed
BEQ LOOP
INPUT_ROUTINE_GOES_HERE
..
..
JMP INPUT

 

 

If you have a lot of keys you want to exclude it's better to create a table of internal key (characters) values and walk through that. Also, you need to input one character at a time in your routine, not whole words at once.

 

 

edit: readability...

Edited February 24, 2011 by Fox-1 / mnx