Programming the Atari XL/XE - Part 11 - Display List Basics (2015)

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  • Опубликовано: 28 янв 2025

Комментарии • 11

  • @timmyt1232
    @timmyt1232 2 года назад

    Hey, Peter. You are an awesome teacher. :)

  • @SimmeringPotpourri
    @SimmeringPotpourri 8 лет назад +2

    Great work! I've read three different books and none of them explained the display list this well.

  • @ascrvideo
    @ascrvideo 6 лет назад

    I have a question like changing a letter of the message "hello world", after an event?

    • @jacofwudsn
      @jacofwudsn  6 лет назад

      What type of event do you mean? Pushsing a fire button or so?

    • @ascrvideo
      @ascrvideo 6 лет назад +1

      clear, or by pressing one of the keys on the keyboard. Remember that the text is already defined but if you want to make it dynamic?

    • @jacofwudsn
      @jacofwudsn  6 лет назад +1

      Now I see. The example of the video show how you can let ANTIC get the data from any memory location. To keep the example short, I've assembled the text there directly.
      Wait for key:
      LDA #$FF
      STA 764
      WAIT_KEY: CMP 764
      BEQ 764
      To change the text you'd simply overwrite it in the memory.
      Means you have to texts prepared in the code and you copy them to the memory location ("screen memory") you defined with the LMS in instruction in the DL
      ldx #7
      copy_text:
      lda new_text,x
      sta screen_memory,x
      dex
      bne copy_text
      new_text: .byte "New text"

    • @ascrvideo
      @ascrvideo 6 лет назад

      thanks for the explanation, following the example of this video I would have to use STA sm, x to change the first eight characters of Hello World, and if I want to change only the first one would be LDA '*' and STA SM to change the letter H for a *, did I understand well?

    • @jacofwudsn
      @jacofwudsn  6 лет назад +2

      Correct, except it would be LDA #"*" or LDA #'* depending on the assembler. # indicates a constant.