====== Programming Blitter ======

''BLTCON''

^15^14^13^12^11^10^9^8^7^6^5^4^3^2^1^0^ ^15^14^13^12^11^10^9^8^7^6^5^4^3^2^1^0^
|  ASH  |||| usea | useb | usec | used |  LF  |||||||| |  BSH  |||| 0|0|0|0| doff | 0|0| efe | ife | fci | desc | 0 |
(normal mode)
  * ''ASH'': shift value of source A
  * ''USEA'': use source A
  * ''USEB'': use source B
  * ''USEC'': use source C
  * ''USED'': use destination D
  * ''LF'': performed logic function minterm select lines
  * ''BSH'': shift value of source B
  * ''DOFF''
  * ''EFE'': exclusive fill
  * ''IFE'': inclusive fill
  * ''FCI'': fill carry input
  * ''DESC'': descending address mode

^15^14^13^12^11^10^9^8^7^6^5^4^3^2^1^0^ ^15^14^13^12^11^10^9^8^7^6^5^4^3^2^1^0^
|  START  |||| 1 | 0 | 1 | 1 |  LF  |||||||| |  TEXTURE  |||| 0|0|0|0| sign | 0|0| sud | sul | aul | sing | 1 |
(line mode)
  * ''START'': sttarting point of line
  * ''LF'': performed logic function minterm select lines
  * ''TEXTURE'':
  * ''SIGN'': sign flag
  * ''SUD'': sometimes up or down
  * ''SUL'': sometimes up or left
  * ''AUL'': always up or left
  * ''SING'':single bit per horizontal line (for filling)


BLTSIZE, BLTSIZEV, BLTSIZEH
^15^14^13^12^11^10^9^8^7^6^5^4^3^2^1^0^
|  h  ||||||||||  w  ||||||

  * ''h'': height in vertical lines
  * ''w'': width in horizontal pixels



===== Blitter's Registers =====
|  BLTCON  | 040  |  2 words  |
|  BLTAFWM  | 044  |  word  |
|  BLTALWM  | 046  |  word  |
|  BLTCPT  | 048  |  2 words  |
|  BLTBPT  | 04E  |  2 words  |
|  BLTAPT  | 050  |  2 words  |
|  BLTDPT  | 054  |  2 words  |
|  BLTSIZE  | 058  |  word  |
|  BLTCONSIZV  | 05C  |  word  |
|  BLTCONSIZH  | 05E  |  word  |
|  BLTCMOD  | 060  |  word  |
|  BLTBMOD  | 062  |  word  |
|  BLTAMOD  | 064  |  word  |
|  BLTDMOD  | 066  |  word  |