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I've spent some time trying to move the NMI interrupt handler & emitter around, and still haven't been able to get things aligned according to the test. I've also made sure to go through the frame timing article in detail, as well as examining the frame timing SVG to make sure that I seem to be ...

(My CPU is passing all of the official opcodes, I just had a screwed up understanding of BIT when reading code... ugg) On to the next problem: I'm passing ppu_vbl_nmi tests 1-4, but on the 5th test (05-nmi_timing.nes) I'm failing, but it's hard for me to understand exactly what the test is doing and...

The mask pattern in A is ANDed with the value in memory to set or clear the zero flag, but the result is not kept. This was my confusion. I forgot that the operand being negative sets P regardless of what the result of the bitwise AND is. However: This wasn't the problem... My debug output was basi...

I'm having trouble getting my (very rough) PPU implementation to pass some of blargg's PPU tests. I'm certain my implementation is to blame, but I'm not sure how to track down the problem. When I run 01-vbl_basics.nes, it does some stuff for awhile and then gets stuck in an infinite loop: E868 2C 02...

Awesome! Thanks guys.

Hey guys and gals, I'm in the process of emulating the CPU. I've been running it against nestest and comparing my CPU state with the Nintendulator log. Finally I've run across something that's stumped me. First: I have emulated no additional hardware. All I'm doing is loading the ROM into memory at ...