Subject: Re: [stella] .byte and B&W questions From: Eckhard Stolberg <Eckhard_Stolberg@xxxxxxxxxxxxxxxxxxxxx> Date: Sat, 17 Jan 1998 16:15:06 +0100 |
>Okay, well, work has begun on my game. And I've got two quick questions. > First, what's the format for ".byte" commands? Specificly, is there any >set number of bytes that must come after (eg, multiple of two, 1, 8, etc)? There are no restrictions. It can be anything between one and whatever you can fit into the codeline. You can usually even mix different number forms like decimal and hexadecimal. >He didn't bother to check the game switches, and goodness knows I haven't >added that yet. What are some possibilities for this mix-up? I've tried >a number of different colors for the background and PF. Right now the >bkgd is black and the PF is off-white. The original program ran in >color. I've got the .bin of my project on my web pages. My mail >handler, Em@iler, won't send attachments unless you compress them, and >.zip isn't an option (I could .hqx for you Mac folk, but it's really not >worth it! ;). In cases like this, sending the souce code would have helped, since it makes analyzing your program a lot easier. But if you want to send BINs you could try UUencoding them by hand and include them in your message. UUencoders and decoders should be available for every operating system. Your program just displays a black screen in PCAE. From what I have seen, you do the colour setting with lines like: LDA $06 STA COLUPF You should change that to: LDA #$06 STA COLUPF The # sign tells the assembler to interpret the following as a number instead of an address. If you leave it out, your program would read the value, that is in the zeropage address 06, and store it into the colour register. Address 06 is for reading collission detection and would have an undefined value. Also your program turns the Vsync signal off for three scanlines before it turns it on for another three scanlines. That is unnessessary. One STA Wsync before the STA Vsync to make sure the Vsync starts at the beginning of the scanline should be enough. Then your program sets the Tim64T timer during the three lines after the STA Vsync. Some TV sets can not sync to that and will produce a rolling picture. To make sure your program will work with most TVs the syncronizing sequence should look like: LDA #$02 LDX #$00 STA VBLANK STA WSYNC STA VSYNC STA WSYNC STA WSYNC STA WSYNC STX VSYNC with nothing between the three STA WSYNC lines. Ciao, Eckhard Stolberg -- Stella list is Administered by krishna@xxxxxxxxxxxx <Glenn Saunders> Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/stella.html +-shameless plugs-------------------------------------------------------+ | Stella documentary at http://www.primenet.com/~krishna | | Nick's VCS links via http://www.primenet.com/~nickb/atariprg.htm | | Write the best game, win framed autographs of famous Atari alumni!! | +-----------------------------------------------------------------------+
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