changelog

 [05/25/03]
 - Fixed a typo that made Z80 banked access to the VDP registers always fail.

 [05/17/03]
 - Modified the rendering code to handle unaligned longword access to memory.

 [04/20/03]
 - Modified 68000 emulator to prevent 'tas.b $mem' from writing data back
   after a read (fixes Gargoyles).
 - Fixed bug in 68000 emulator to swap order of words written for address
   register indirect pre-decremented writes (fixes Jim Power graphics).
 - Added support for 240-line displays (for Super Skidmarks).
 - Rewrote part of the interrupt handling (fixes some raster effects).
 - Removed sprite collision detection code (never really worked).
 - Optimized sprite rendering inner loop.

 [04/13/03]
 - Finished up memory map for VDP DMA V-bus reads.
 - Fixed handling of 68000 writes to I/O chip at even addresses.
 - Fixed bit 7 handling of control register in I/O chip.
 - Finished up Z80 memory map.
 - Added code to handle Genesis hardware lock-ups.
 - Removed some faulty code from the 68000 memory map handlers.

 [03/22/03]
 - Completed implementation of Z80 banked memory handlers.