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 AUSEA
: use source AUSEB
: use source BUSEC
: use source CUSED
: use destination DLF
: performed logic function minterm select linesBSH
: shift value of source BDOFF
EFE
: exclusive fillIFE
: inclusive fillFCI
: fill carry inputDESC
: 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 lineLF
: performed logic function minterm select linesTEXTURE
:SIGN
: sign flagSUD
: sometimes up or downSUL
: sometimes up or leftAUL
: always up or leftSING
: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 linesw
: 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 |