Window Streams in ASM?

[Typhon]

Dear all,

How do you work with window streams in Assembler using the Firmware? I've got the following piece of code to set up a Window #1 over the top half of the screen:

        ld      a, 1                    ; Switch to Stream #1
        call    TXT_STR_SELECT 
        ld      h, 1
        ld      d, 39
        ld      l, 2
        ld      e, 21
        call    TXT_WIN_ENABLE          ; Define a Window over the Playing Area
                                        ; as Stream #1
        ld      a, 0
        call    TXT_SET_PAPER                 
        ld      a, 0                    ; Swap back to the default Stream (#0)
        call    TXT_STR_SELECT

However, selecting the stream using TXT STR SELECT and then clearing it with TXT CLEAR WINDOW doesn't seem to clear it. (these defines are to the corresponding firmware calls from SOFT968)

        ld      a, 1                    ; Switch to Stream #1
        call    TXT_STR_SELECT
        ld      a, 0
        call    TXT_SET_PAPER
        call    TXT_CLEAR_WINDOW        ; Clear it
        ld      a, 0
        call    TXT_STR_SELECT          ; Switch back to Default Stream (#0)

What am I missing?

[Rabs]

Seems to work ok for me.

I simply added the TxtClearWindow call to one of my routines which uses streams and the selected window was cleared.

This is the firmware call I used;

Code Select Expand

/*
036   &BB6C   TXT CLEAR WINDOW
      Action: Clears the window (of the current stream) and moves the
              cursor to the top left corner of the window
      Entry:  No entry conditions
      Exit:   AF, BC, DE  and  HL  are  corrupt,  and  alI others are
              preserved

*/
TxtClearWindow=#BB6C
And this is the code where I call it and sure enough it clears that window. Only difference is I don't have the Set Paper call before it, I just clear the window.

Code Select Expand

; Print PIO Port A Value in Window 1
;
;
PrintPIOPortA:  
   ;Select window 1
    ld a,1
    call FwTxtStrSelect

    ld a, (PIOPortA)
    call Bin2Hex
   
    ;Print Most Significant Char
    ld a,h
    call FwTxtWrChar

    ;Print List Significant Char
    ld a,l
    call FwTxtWrChar

    ld a,#0D
    call FwTxtOutput
    ld a,#0A
    call FwTxtOutput

    call TxtClearWindow

   ret
You can see the effect below where the window for Port A is now cleared, should have text in it.

You cannot view this attachment.

[Typhon]

Let me look at my code further, and remove the paper call, there might be a logic issue or something. That example you have is very well explained. Thank you once again!

[Typhon]

Still doesn't work for some reason, but I think it might be a timing issue. In any case, I'm not going to worry about it. There WAS a missing call to erase some old characters anyway, so things weren't right anyway.

[Rabs]

You defined txt clear window as;

TXT_CLEAR_WINDOW EQU #BB63 ; Clear the current Window

I have it as BB6C.

BB63 is TXT SET GRAPHIC.

[Typhon]

Ahahahahaha! How did I miss that! That's exactly what the problem was!

I'm such a pillock.

THANK YOU.