[Coco] strange behaviour

Arthur Flexser flexser at fiu.edu
Wed Jun 16 13:00:35 EDT 2004


My memory is a bit hazy here, but I think POLCAT, as called by the vector,
doesn't necessarily assume that input is to be from the keyboard, as
opposed to, say, a disk file.  You may have to clear $6F, the device
number, for it to work as you intend.  Or call POLCAT directly at $A1C1,
which does assume keyboard input.

Art

On Wed, 16 Jun 2004, James Dessart wrote:

> 
> On 15-Jun-04, at 10:59 PM, Roger Taylor wrote:
> 
> > The only place you seem to be setting ___ungetched_char is when you 
> > clear it with clra/sta, yet you're checking it for a character upon 
> > entry into the code.
> 
> That part, believe it or not, is correct. It gets set elsewhere, in 
> another assembly routine. The part that really seems to be giving me 
> trouble is this:
> 
> read_key:
> 	jsr	[0xA000]  ; call POLCAT
> 	beq	read_key
> 
> where the routine will stay in a loop even if I press a key. The BASIC 
> manual says that Z will be 1 upon finding no key pressed, but 0 if it 
> is pressed. But my code doesn't seem to be reacting that way.
> 
> Thanks,
> James
> 
> 
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