1.1 --- a/ULA.txt Fri Mar 06 01:13:10 2015 +0100
1.2 +++ b/ULA.txt Fri Mar 06 01:13:44 2015 +0100
1.3 @@ -359,8 +359,15 @@
1.4 bottom 6 lines blank.
1.5
1.6 See the description of the display suspend enhancement for a more efficient
1.7 -way of blanking lines whilst allowing the CPU to perform useful work during
1.8 -the blanking period.
1.9 +way of blanking lines than merely blanking the palette whilst allowing the CPU
1.10 +to perform useful work during the blanking period.
1.11 +
1.12 +To control the blanking or suspending of lines at the top and bottom of the
1.13 +display, a memory location could be dedicated to the task: the upper 4 bits
1.14 +could define a blanking region of up to 16 lines at the top of the screen,
1.15 +whereas the lower 4 bits could define such a region at the bottom of the
1.16 +screen. If more lines were required, two locations could be employed, allowing
1.17 +the top and bottom regions to occupy the entire screen.
1.18
1.19 Enhancement: Screen Height Adjustment
1.20 -------------------------------------
1.21 @@ -537,6 +544,10 @@
1.22 performance benefit would be derived from giving the CPU full access to the
1.23 memory bandwidth.
1.24
1.25 +The region blanking feature mentioned above could be implemented using this
1.26 +enhancement instead of employing palette blanking for the affected lines of
1.27 +the display.
1.28 +
1.29 Enhancement: Memory Filling
1.30 ---------------------------
1.31