HHPOSW/HHPOSR
Address Name Description
DFF1D8 HHPOSW DUAL mode hires Hbeam counter write
DFF1DA HHPOSR DUAL mode hires Hbeam counter read

Overview

This the secondary beam counter for the faster mode, triggering the
UHRES pointers & doing the comparisons for HBSTRT,
HBSTOP, HTOTAL, HSSTRT, HSSTOP (See HTOTAL for bits)

This material is most likely derived from the official Amiga documentation and where applicable copyright remains with the original author.