Atari ST series Technical Reference Manual page 338

Mode
Logic Operation
D1 = D
9
10 D1 = S XOR D
11 D1 = S OR D
12 D1 = NOT (S OR D)'
D1 = NOT (S XOR D)
13
14 D1 = NOT D
15 D1 = S OR (NOT D)
16 D1 = NOT S
17 D1 = (NOT S) OR D
D1 = NOR (S AND D)
18
19 D1 = 1
+ 038 to +039
This location, and the three following, are often used to hold
x and y coordinates for drawing.
+ 040 to +041
See above.
+ 042 to +043
See above.
+ 044 to +045
See above.
+ 046 to +049
Pointer to the current fill pattern.
+ 050 to +051
This value is ANDed with Y l, and used as an index into the
fill pattern. In most cases, the correct value will be the length
of the pattern (in lines) minus one.
+ 052 to +053
Multiplane fill pattern flag. A zero indicates a single plane fill
330
APPENDIX H
Destination unchanged
XOR mode
Transparent mode
Reverse transparent mode
Fill destination block
XI
Y1
X2
Y2
PATPTR
PATMSK
MFILL
Description
( + $026 to +$027)
( + $028 to +$029)
( + $02A to + $02B)
( + 02C to + $02D)
( + $02E to +$031)
( + $032 to +$033)
( + 034 to + $035)