View source for User:PostNES

[http://bootgod.dyndns.org:7777/stats.php?page=6 NesCartDB: Top 10 mappers used]:
{|
! by usage
|-
|{{mapper|001}} <br /> {{mapper|004}} <br /> {{mapper|002}} <br /> {{mapper|000}} <br /> {{mapper|003}} <br /> {{mapper|007}} <br /> {{mapper|206}} <br /> {{mapper|011}} <br /> {{mapper|005}} <br /> {{mapper|019}} <br />
|}
{|
! ascending
|-
|{{mapper|000}} <br /> {{mapper|001}} <br /> {{mapper|002}} <br /> {{mapper|003}} <br /> {{mapper|004}} <br /> {{mapper|005}} <br /> {{mapper|007}} <br /> {{mapper|011}} <br /> {{mapper|019}} <br /> {{mapper|206}} <br />
|}

== Mapper ideas ==

* CHR hardware scrolling unit
** Scrolls portions of pattern table with wrapping for hardware accelerated parallax effects
*** implementation: two CHR ROMs with alternately stored tiles (VRAM address <tt>%0AAAAA AAAcBBBB</tt> -> ROM <tt>%c</tt>, address in ROM <tt>%AAAAAAAABBBB</tt>) for parallel fetching of pixel rows

* CHR color remapping unit
** ExGraphix-like, with each byte in ExRAM storing a color index (0-3) to be remapped to in a character, for every source color index (0-3). This would allow to conserve some palette/CHR-ROM space in some cases. <br /> Example: 
<pre>
ExRAM byte = %01010000, or 1100 in quaternary system: remap 0 to 0, 1 to 0, 2 to 1, 3 to 1

Original character:
.defchr $00000000,
        $02233200,
        $02100120,
        $03000030,
        $03333310,
        $03000030,
        $03000030,
        $03222210

Remapped:
.defchr $00000000,
        $01111100,
        $01000010,
        $01000010,
        $01111100,
        $01000010,
        $01000010,
        $01111100
</pre>

* DPCM converter
** Converts any on-cartridge audio to DPCM and returns it to CPU on sample reads so that there's audio expansion on NES!
*** DMC rate control would coarsely alter pitch if the conversion rate is constant

* DPCM hardware mixer
** Plays back (by returning to CPU on sample read) multiple samples at different speeds