Add feature list
GFX: implement 32 horizontal cell mode
SOUND: bump frequency used for YM2612 (trying to fix bugs)
VDP: handle DMA transfer with 0 bytes
Triple screen output to help debug
VDP: clear codereg when a register is written to
VDP: fix typo in vcounter calculation
VDP: do not generate HINT during vblank
GFX: rewrite draw_plane_ab to mimic the hardware (no behaviour change)
GFX: implement per-column scrolling
VDP: accurate hcounter emulation
MEM: Implement 8bit access to IO
Update
SOUND: fix DAC sounds by running YM2612 emulator each line
GFX: implement correct inter-sprite priorities
Update
Z80: reset YM2612 anytime the reset line is asserted
Sync Z80 on busreq write
VDP: overall improve accuracy (1st page of vdpfifotesting)
VDP: further accuracy fixes (vdpfifotesting page 2)