Mega Man 2 + Rockman 2 MMC3 Conversion
Hack of Mega Man 2
| Released By | 5323 |
| Category | Improvement |
| Platform | NES |
| License | CC-BY-SA-4.0 |
| Patching Information | No Special Requirements |
| Genre | Action > Platformer |
| Mods | O |
| Game Date | Dec 24 1988 |
| Patch Version | 1.0 |
| Release Date | Jan 21 2023 |
| Readme | Yes |
| Last Modified | Jan 22 2023 |
Game Description:
Mega Man 2 is a platforming game for the Nintendo Entertainment System.
Following the gameplay of the first Mega Man game, Mega Man 2 has new features, like Robot Master stages increased from 6 to 8, E-cans that replenishes health to 100%, and support items/platforms 1, 2, and 3.
After his defeat, Dr. Wily created his own Robot Masters and continued his desires for world domination. Mega Man is the only one who can stop the evil scientist once again. But before he could reach him, he needs to defeat Dr. Wily's Robot Masters and obtain new powers from them.
Following the gameplay of the first Mega Man game, Mega Man 2 has new features, like Robot Master stages increased from 6 to 8, E-cans that replenishes health to 100%, and support items/platforms 1, 2, and 3.
After his defeat, Dr. Wily created his own Robot Masters and continued his desires for world domination. Mega Man is the only one who can stop the evil scientist once again. But before he could reach him, he needs to defeat Dr. Wily's Robot Masters and obtain new powers from them.
Hack Description:
This patch converts MM2/RM2 to use the MMC3 mapper, allowing both larger ROMs (up to 512 KB PRG-ROM) and 2 switchable 8-KB banks, offering much greater flexibility for derivative hacks. Additionally, while this patch is primarily intended for hackers making their own MM2 hacks, it does slightly reduce lag, reducing CPU usage in the base game by about 0.6%, as well as fix the delay-scroll bug.
There were several motivations to create yet another MM2 MMC3 conversion.
1. Poor optimization. The previous MMC3 conversion adds an additional +25 cycles to each bank switch. While this doesn't sound like much, bank switches are observed to occur up to 25 times per frame (1500 per second). 25x25 cycles/frame add up to over 2% of the CPU, which directly increases lag. In contrast, this patch is actually slightly faster than the original game (-7 cycles per bank switch).
2. The previous conversion's banking implementation is not preemption-safe. That is, it is not safe to use 8 KB banks outside the NMI because the NMI handler reverts to 16 KB banking each frame. This patch provides preemption-safe bank-switching APIs for use outside the NMI.
3. This patch inherently fixes the delay-scroll bug present in the original game and the previous conversion.
Patches for both Mega Man 2 and Rockman 2 are included.
There were several motivations to create yet another MM2 MMC3 conversion.
1. Poor optimization. The previous MMC3 conversion adds an additional +25 cycles to each bank switch. While this doesn't sound like much, bank switches are observed to occur up to 25 times per frame (1500 per second). 25x25 cycles/frame add up to over 2% of the CPU, which directly increases lag. In contrast, this patch is actually slightly faster than the original game (-7 cycles per bank switch).
2. The previous conversion's banking implementation is not preemption-safe. That is, it is not safe to use 8 KB banks outside the NMI because the NMI handler reverts to 16 KB banking each frame. This patch provides preemption-safe bank-switching APIs for use outside the NMI.
3. This patch inherently fixes the delay-scroll bug present in the original game and the previous conversion.
Patches for both Mega Man 2 and Rockman 2 are included.
ROM / ISO Information:
Mega Man 2 (USA):
PRG-ROM CRC32 0FCFC04D / MD5 0527A0EE512F69E08B8DB6DC97964632
File CRC32 5E268761 / MD5 8E4BC5B03FFBD4EF91400E92E50DD294
File CRC32 80E08660 / MD5 302761A666AC89C21F185052D02127D3
File CRC32 A9BD44BC / MD5 CAAEB9EE3B52839DE261FD16F93103E6
-
Rockman 2:
PRG-ROM CRC32 6150517C / MD5 770D55A19AE91DCAA9560D6AA7321737
File CRC32 30B91650 / MD5 055FB8DC626FB1FBADC0A193010A3E3F
PRG-ROM CRC32 0FCFC04D / MD5 0527A0EE512F69E08B8DB6DC97964632
File CRC32 5E268761 / MD5 8E4BC5B03FFBD4EF91400E92E50DD294
File CRC32 80E08660 / MD5 302761A666AC89C21F185052D02127D3
File CRC32 A9BD44BC / MD5 CAAEB9EE3B52839DE261FD16F93103E6
-
Rockman 2:
PRG-ROM CRC32 6150517C / MD5 770D55A19AE91DCAA9560D6AA7321737
File CRC32 30B91650 / MD5 055FB8DC626FB1FBADC0A193010A3E3F
Files:
- Readme File
- Patch File
Screenshots:
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