Search found 177 matches

by albailey
Thu Feb 11, 2010 11:59 am
Forum: General Stuff
Topic: your development environment
Replies: 27
Views: 7271

I use vi in cygwin as my editor. I use CA65 as my assembler I use my own tools for graphics. I dont do music. I primarily use FCEUltra 0.98 as my emulator. This is because I find it the easiest to view the memory in. Since I busted my powerpak, I'll likely go back to eproms and test carts for real h...
by albailey
Thu Oct 08, 2009 10:43 am
Forum: NESdev
Topic: M.C. Kids and old platform game programming concepts
Replies: 11
Views: 4830

BTW, players should be able to move up through air... don't characters jump in your game? =) Actually, I got sick of re-writing the engine over and over so I've attempted to go with a table based approach. Unfortunately I think this has limitations too, but I wont know till I hit them. My player ha...
by albailey
Tue Oct 06, 2009 8:47 am
Forum: NESdev
Topic: M.C. Kids and old platform game programming concepts
Replies: 11
Views: 4830

I've been wondering about techniques for this as well. For example, I've tried declaring certain areas of my map as different object types. At the moment I support 4. - Air - Solid - Stairs - Cover My player can move left and right and down(fall) through air, but not up. He cannot move at all throug...
by albailey
Fri Sep 04, 2009 3:03 pm
Forum: NESemdev
Topic: 6502 Instruction Timing Tests
Replies: 45
Views: 19698

Sorry to bump an old thread, but I'm encountering an error in cpu_timing_test6 and the readme says to post questions and I'm not sure what I'm doing wrong. Fail OP: $40 UNKNOWN ERROR $FEDF $40 is an RTI and the readme says that RTI can be a special case that might reveal non timing problems in an em...
by albailey
Wed Aug 19, 2009 6:20 pm
Forum: NESemdev
Topic: Is there a test rom for CPU timing (ie extra branch cycles)
Replies: 6
Views: 5896

Wow. That folder has all sorts of goodies. Thanks (and Thanks to Blargg as well)

And yes, by isolate I meant "unit test" individual instructions.
It turns out I'm not as close to completing the CPU as I thought.

Al
by albailey
Wed Aug 19, 2009 7:30 am
Forum: NESemdev
Topic: Is there a test rom for CPU timing (ie extra branch cycles)
Replies: 6
Views: 5896

Thanks. Using the one by Blargg I can now see I still have more errors to fix.

Is there anything that isolates page boundary crossed opcode timing
(ex: adding a cycle when certain instructions like ADC Absolute,X crosses a page boundary)

Al
by albailey
Tue Aug 18, 2009 5:36 pm
Forum: NESemdev
Topic: Is there a test rom for CPU timing (ie extra branch cycles)
Replies: 6
Views: 5896

Is there a test rom for CPU timing (ie extra branch cycles)

I have nestest running and all the tests are passing. I've been working on my PPU and wanted to start to run some of those test ROMS, but I've discovered I'm not going to be able to pass many of the PPU timing tests since my CPU instructions are not actually timed properly. For example, I was forget...
by albailey
Mon May 25, 2009 10:04 am
Forum: Newbie Help Center
Topic: Question about detecting a PAL or NTSC environment
Replies: 17
Views: 7412

Brian, have you tried clearing $4000 and $4001 using your routine.
I dont know if it will change anything, but if it does it might imply an unknown state of those registers during reset.
Al
by albailey
Mon Mar 23, 2009 12:20 pm
Forum: Newbie Help Center
Topic: Least Hassle-free way for a run of cartridges?
Replies: 15
Views: 6747

I did a run of 100 carts using donors and I can guarantee I would never do it that way again.

On the plus side, I eventually got good at using de-soldering braid.

Go with retrozone.

Al
by albailey
Thu Feb 26, 2009 2:40 pm
Forum: Newbie Help Center
Topic: Writing bits 12-14 in VRAM address via $2006
Replies: 22
Views: 10867

I second that.
Al
by albailey
Wed Feb 04, 2009 2:16 pm
Forum: NESemdev
Topic: What ROMs should I use when writing an emulator
Replies: 2
Views: 2740

What ROMs should I use when writing an emulator

I've noticed that a lot of people mention a particular game to verify that a particular feature of their emulator is working. Is there a list or checklist for this anywhere? I am thinking each mapper has a particular rom that works best at excercising all that mapper's features, but many roms might ...
by albailey
Tue Jan 13, 2009 7:35 am
Forum: Newbie Help Center
Topic: Controller Input Subroutines: How many?
Replies: 33
Views: 9716

Here's a good method. Store the address of the controller routine at say $40/$41 in ZP. Then when you want to go to the controller routine, do JMP ($40). So if you want to point to a different controller routine, change $40/$41 to the address of the desired routine. I use this approach for a lot of...
by albailey
Mon Jan 05, 2009 1:08 pm
Forum: Newbie Help Center
Topic: What do we need to know to create a NES emulator?
Replies: 4
Views: 2381

I actually started working on an emulator not too long ago. I started with the 6502 CPU. The problem was, how to test it. So I worked on a disassembler, which is really just a tracer. I had my own code which I could compare to the traced output. It ended up helping a lot. I ended up breaking the dis...
by albailey
Tue Dec 30, 2008 8:58 am
Forum: NESemdev
Topic: PPU scanline cycles question
Replies: 1
Views: 2187

PPU scanline cycles question

So I spent last weekend getting a PPU working. I can now see some basics, but I still have a way to go. Much thanks to all you guys who have contributed so much solid information. I am trying to figure out the proper behaviour for each PPU cycle of a visible scanline. I checked the wiki and it has s...
by albailey
Wed Dec 10, 2008 11:33 am
Forum: NESdev
Topic: Artificial Blank - How can it be done.
Replies: 8
Views: 3688

I suspect what is he asking is about doing a split screen effect. You can use sprite 0 to do this for one split. I think he wants two. So what I think he wants to do is that after that first hit occurs, clear the sprite 0 hit bit, set a new location for sprite 0 (through DMA or the gbaguy way with w...