This is a post on a bug that broke Fatal Rewind for the Sega Genesis, a port of the Amiga/Atari ST game The Killing Game Show.
I’m not sure why some Amiga-to-Genesis ports changed the game’s title. Leander is another one, which got ported to Genesis under the title Galahad.
Rather than covering a single game, this is a topic post that covers six different bugs in my implementation of the Game Boy Color’s HDMA feature (HBlank direct memory access). Not every GBC game uses this feature, but a decent number do, and a few games will break pretty badly if it’s not emulated fairly accurately (moreso in terms of behavior than timing).
This is maybe the start of a series of posts on games/software that exposed bugs in one of my emulators, depending on how many I find interesting enough to write about. In most cases I think the interesting part is usually the game behavior that triggered the bug rather than the bug itself.
Donkey Kong Country 2 has a pretty well-known bug in the old SNES emulator ZSNES where some stages have spinning barrels that don’t work properly. One of the earliest pictured here, in the first stage of Krem Quay (third world):
After you jump into the barrel, you’re supposed to be able to completely control its rotation by pressing left and right on the d-pad, with the barrel only rotating while you’re holding left or right.
This is the seventh and final post in a series on emulating the main Sega Genesis sound chip, the YM2612.
Part 1 - Interface Part 2 - Phase Part 3 - Envelopes Part 4 - Digital Output Part 5 - Analog Output Part 6 - LFO This post will cover the envelope generator’s SSG-EG mode.
This is the sixth in a series of posts on emulating the main Sega Genesis sound chip, the YM2612.
Part 1 - Interface Part 2 - Phase Part 3 - Envelopes Part 4 - Digital Output Part 5 - Analog Output This post will cover the hardware timers, the LFO (low frequency oscillator), and synthesized effects powered by the LFO.
This is the fifth in a series of posts on emulating the main Sega Genesis sound chip, the YM2612.
Part 1 - Interface Part 2 - Phase Part 3 - Envelopes Part 4 - Digital Output This post will cover a few aspects of the YM2612’s audio hardware, particularly the DAC (digital-to-analog converter), that are not strictly related to sample generation but do noticeably affect the sound of the final output.
This is the fourth in a series of posts on emulating the main Sega Genesis sound chip, the YM2612.
Part 1 - Interface Part 2 - Phase Part 3 - Envelopes This post will describe how the chip computes operator and channel outputs given the phase generator and envelope generator outputs.
This is the third in a series of posts on emulating the main Sega Genesis sound chip, the YM2612.
Part 1 - Interface
Part 2 - Phase
This post will describe how the ADSR envelope generators work.
ADSR Each of the YM2612’s 24 operators has its own ADSR envelope generator that automatically adjusts the operator’s volume over time.
This is the second in a series of posts on emulating the main Sega Genesis sound chip, the YM2612.
Part 1 - Interface
This post will describe the FM synthesis channels’ phase generators.
Phase Generation Each of the YM2612’s 24 operators contains a phase generator and an ADSR envelope generator.