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NAME rev ADDR type chip Description
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DIWHIGH p 1E4 W A D Display window upper bits for start, stop
This is an added register for Hires chips, and allows
larger start & stop ranges. If it is not written, the above
(DIWSTRT,STOP) description holds. If this register is written,
direct start & stop positions anywhere on the screen.
It doesn`t affect the UHRES pointers.
BIT# 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
X X H10 H1 H0 V10 V9 V8 X X H10 H1 H0 V10 V9 V8
(stop) | (start)
Take care (X) bits should always be written to 0 to
maintain upwards compatibility. H1 and H0 values define
70ns amd 35ns increments respectively, and new LISA bits.
Note: In all 3 display window registers, horizontal bit
positions have been renamed to reflect HIRES pixel
increments, e.g. what used to be called H0 is now referred to as H2.