diff options
author | RobertoFresca <robbie@mamedev.org> | 2016-05-28 13:09:29 -0300 |
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committer | RobertoFresca <robbie@mamedev.org> | 2016-05-28 13:09:29 -0300 |
commit | cc87a10563fb115e6d6366efd2e73faf687aebdc (patch) | |
tree | efe77d100078b7ae9e9be9878c111c0ca745d73b | |
parent | 958731ef5aef0e2357bd03f597e0ec06f893d309 (diff) |
Me Tarzan, you Jane....
-rw-r--r-- | src/mame/drivers/magicfly.cpp | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/src/mame/drivers/magicfly.cpp b/src/mame/drivers/magicfly.cpp index 149f3864806..4dec074f4ed 100644 --- a/src/mame/drivers/magicfly.cpp +++ b/src/mame/drivers/magicfly.cpp @@ -253,23 +253,23 @@ ******************************************************************************* - After check the last bit of $1800, code jump into a loop ($DA30)... + After check the last bit of $1800, the code jumps into a loop ($DA30)... BEHAVIOUR OF BOOT CHECK (magicfly): - 1) Fill the video RAM with spaces (0x20), and color RAM with 0x15. - 2) Check bit 7 of $1800 (video RAM, 1st offset) if activated. + 1) Fills the video RAM with spaces (0x20), and color RAM with 0x15. + 2) Checks bit 7 of $1800 (video RAM, 1st offset) if it's active. 3) If true, go to $DA30 (incremented fill infinite loop). - 4) If not, fill the video RAM with spaces (0x20), and color RAM with 0x1F. - 5) Check bit 7 of $1800 (video RAM, 1st offset) if activated. + 4) If not, fills the video RAM with spaces (0x20), and color RAM with 0x1F. + 5) Checks bit 7 of $1800 (video RAM, 1st offset) if it's active. 6) If not, go to $DA30 (incremented fill infinite loop). - 7) If true, returns and continue to NORMAL GAME. + 7) If true, returns and continues to NORMAL GAME. Since bits 0-2 are for regular colors, seems that bit 3 in color RAM (bit 2 for 7mezzo) is mirrored to bit 7 through a kind of device. This is the only explanation I found to allow a normal boot, and seems to be - created as a protection method that don't allow owners to use a ROM-swap on + created as a protection method that doesn't allow owners to do a ROM-swap on their boards, converting from one game to another. |