moohost.blogg.se - Sega cd bios bin

SEGA CD BIOS BIN CODE

In GG mode, this port is for the Gear to Gear Cable, and reading it returns what was written in SMS mode, its This BIOS writes and reads two bytes to and from port $02, in order toĭetect if it is in GG mode or SMS mode so it can use the correct

The jump and punch buttons were reversed (to the more common layout where 2 = jump).

The rice cake Alex Kidd eats before each level was changed to a hamburger (to better suit Western audiences).

The title screen copyright date is 1990 instead of 1986.

The game is almost the same as the cartridge version, except that:

SEGA CD BIOS BIN CODE

Game) meant that the checksumming code was minimised and was moreįeasible to insert into unused space in game with an almost-full ROM.

The removed items ("Master System" logo, animation, music, "Snail Maze" The $2 checksum range bug isįixed, even though the previously released incompatible BIOSes meant that Its checking routines are almost identical to those of the US/European This BIOS features a different bumper screen to previous versions, with US/European BIOS with Alex Kidd in Miracle World bumper screen US/European BIOS with Alex Kidd in Miracle World (1990) Has plenty of unused space for the BIOS routines to be added. If no game is found, instead of showing an information screen, it runsĪ copy of Hang On and Safari Hunt built in to the BIOS ROM. Restore the current mapped bank (assuming a Sega It additionally includes support in the checksum routines to save and Lookup table preceding it), which was overlooked in this version, the $2Ĭhecksum range will not be correctly summed. Version (where an opcode's first byte is used as the last byte of the However, due to an overzealous optimization in that This aspect of its operation is almost identical to the US/European Master If not, it checks for valid data on the three slots.

It runs the same "Snail Maze" secret game as the US/European Master If, at the end of this phase,īuttons + + are being pressed on controller 1 (and no other buttons), This BIOS shows the same bumper screen as the US v1.3 BIOS (except theĭate is changed to 1988). US/European BIOS v2.4 with Hang On and Safari Hunt (1988) It doesn't store the commonly used VDP routines (WriteVRAMByte, etc.) at the beginning of the ROM to take advantage of the rst opcodes.Data for the SEGA and Master System logos are stored uncompressed (the Phantasy Star Tile Decoder code is not present).The frame interrupt handler is never called, as the interrupt is never enabled.The ROM detection port is the same as 1.3, except it doesn't read port $dc, and doesn't distinguish between "no ROM" and "invalid region ROM".The detection code is copied and called earlier, and instead of the fixed wait of ~1.67s in 1.3, there is a variable wait based on the size of the ROM detected: no ROM: ~1.67s, 8KB => 1.55 s, 16KB => 1.43 s, 32KB => 1.19 s, 48KB => 0.95 s, 64+KB => no wait.Instead, it displays a simple error screen that just contain the strings "MASTER SYSTEM (c) SEGA 1986", "S/R V1.0", and a blinking "?" If the checksum test fails, there is an extra "CHECK SUM ERROR" string before the "?" Instruction screen when no game is found.Snail Maze game (the game songs are all present, and are almost exactly the same as in 1.3, but the rest of the game is not there).Sound (the entire sound engine code is there, and is almost exactly the same as in 1.3.This BIOS also contains the sound data for an early version of the Sega two-tone "jingle", but it doesn't sound right/finished. Animated SEGA / Master System bumper screen it just appears.