nesdev.org

THANK YOU SO MUCH!

Thank You!

well, yes, nintendulator is usually under that message screen. But, here and now, i just see the next window opened behind it. No nintendulator at all (but it says it is running at the bottom of the screen ) Thank you.

hi Now, after you open up Nintendulator, you cant see it. You can only see the window that opens saying "Emulation switched to NTSC". Clicking maximize brings it back, but it's full screen. i cant really use it like that. Please, how can this be fixed? i've tried deleting Nintendulator and...

Just did a test while shooting up. FF.04 (a value for decrementing each time) * 1.80 (movement speed) ----------- 17E.8600 (a new value for decrementing each time) That's the answer that Windows Calculator gives. Well, it matches my programs answer.. 7E.86 So the multiplication is correct. And decre...

When multiplying aa.bb by cc.dd, aa.bb is the spead variable and cc.dd is the value added to the y value each time. aa is 1, for now, so i dont have to worry about sign extending bb. But, cc might need to be signextended if cc is 0. So i added this code after (giving speed variable a value) and befo...

Yes, Thank You, it should be FE80. But, the numbers, after multiplying, add up to 7E80. The multiply procedure works. So the code that figures out aa.bb * cc.dd could not be working. But, it only messes up when firing in a decreasing direction.

This one is really hard.

ok, i hope this is the question i should ask. When shooting directly down, for the y-values, it reads: 48, 49, 4B, 4C, 4E (constant addition of $0180 (not including decimal part for these examples)) When shooting directly up, for the y-values, it reads: 92, 10, 8F, 0D, 8C (constant addition of $7E80...

Thank You for telling me about cmp! :) My game has a very odd problem now. If i fly toward the bottom of the screen and fire directly up, the bullet disappears mid screen. While at the bottom and firing up, first the y value is $A0. And as it continues flying up the yvalue decreases to $94, then $8B...

You should think about printing this out.

http://users.telenet.be/kim1-6502/6502/pm-apndx.html

and this one is quick and to the point (greatly helped me with addressing modes):

http://nesdev.com/6502guid.txt

(Thank You tepples, the classic multiplying 16 bits by 16 bits algorithm really helped me!) How do you set boundaries? After increasing the speed of my bullet, i noticed that sometimes it will cross the screen two or three times. My code for checking the y boundary of the screen is like this: lda bu...

Multiplying two two byte numbers is hard. Here is my attempt (A,B,C,and D are variables.) A.B x C.D ----- step1 = D * B step2 = carry_from_step3 + C * A step3 = C * B step4 = carry_from_step1 + D * A step1 x 1 = val1 step2 x 100 = val2 step3 x 10 = val3 step4 x 10 = val4 val1 + val2 + val3 + val4 = ...

Having problems. Here's the code: ;************** ; movement_speed start ;************** lda #$10 sta speed lda y_portion_decimal ;sta look2 sta multiplicand lda speed asl asl asl asl ;sta look4 jsr multiply lda product ;sta look6 sta bullettable+1 ;y_portion_decimal lda y_portion ;sta look sta mult...

www.freewebs.com/the_bott/ScrollSpeedTest.nes That was useful to me for figuring out how fast and slow the one byte speed method could go. (7+15/16th and 1/16th) ---------- Well, i tried the one byte method and it ended up using two bytes. Here's what's there: lda $18 sta speed lda speed and #%0000...

That is interesting! Here is some code: Although machines often have efficient built-in instructions for performing arithmetic and logical operations, in fact all these operations can be performed just by combining the bitwise operators and zero-testing in various ways. For example, here is a pseudo...