Triangle Drawing Registers - Fujitsu MB86R02 Jade-D Hardware Manual

MB86R02 'Jade-D' Hardware Manual V1.64
18.11.7

Triangle drawing registers

Each register is used by the drawing commands. The registers cannot be accessed from the CPU or
using the SetRegister command.
(XY coordinates register)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Register Address
Ys 0000 S S S S
H
Xs 0004 S S S S
H
dXdy 0008 S S S S
H
XUs 000c S S S S
H
dXUdy 0010 S S S S
H
XLs 0014 S S S S
H
dXLdy 0018 S S S S
H
USN 001b 0 0 0 0
H
LSN 0020 0 0 0 0
H
Address Offset value from DrawBaseAddress
S Sign bit or sign extension
0 Not used or 0 extension
Int Integer or integer part of fixed point data
Frac Fraction part of fixed point data
Sets (X, Y) coordinates for triangle drawing
Ys Y coordinates start position of long edge
Xs X coordinates start position of long edge corresponding to Ys
dXdy X DDA value of long edge direction
XUs X coordinates start position of upper edge
dXUdy X DDA value of upper edge direction
XLs X coordinates start position of lower edge
dXLdy X DDA value of lower edge direction
USN Count of spans of upper triangle. If this value is "0", the upper triangle is not drawn.
LSN Count of spans of lower triangle. If this value is "0", the lower triangle is not drawn.
18-228
Int
Int
Int
Int
Int
Int
Int
Int
Int
Frac
Frac
Frac
Frac
Frac
Frac
Frac
0
0