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C64: [VIC2] don't enable SR reload outside the display area

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This commit is contained in:
Gyorgy Szombathelyi
2020-04-24 18:31:56 +02:00
parent 51da86634c
commit 3e7e798774
1 changed files with 10 additions and 3 deletions
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13
cores/c64/rtl/video_vicII_656x_a.vhd
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@@ -47,6 +47,7 @@ architecture rtl of video_vicii_656x is
signal vicCycle : vicCycles := cycleRefresh1;
signal sprite : unsigned(2 downto 0) := "000";
signal shiftChars : boolean;
signal shiftLoadEna : boolean;
signal idle: std_logic := '1';
signal rasterIrqDone : std_logic; -- Only one interrupt each rasterLine
signal rasterEnable: std_logic;
@@ -623,15 +624,21 @@ vicStateMachine: process(clk)
end process;
-- -----------------------------------------------------------------------
-- Generate ShiftChars flag
-- Generate ShiftChars and ShiftLoadEna flags
-- -----------------------------------------------------------------------
process(rasterX)
process(rasterX, rasterXDelay)
begin
shiftChars <= false;
if rasterX(9 downto 3) > "0000001"
and rasterX(9 downto 3) <= "0101001" then
shiftChars <= true;
end if;
shiftLoadEna <= false;
if rasterXDelay(9 downto 3) > "0000010"
and rasterXDelay(9 downto 3) <= "0101010" then
shiftLoadEna <= true;
end if;
end process;
-- -----------------------------------------------------------------------
@@ -918,7 +925,7 @@ calcBitmap: process(clk)
--
-- Reload shift register when xscroll=rasterX
-- otherwise shift pixels
if xscroll = rasterXDelay(2 downto 0) then
if shiftLoadEna and xscroll = rasterXDelay(2 downto 0) then
shifting_ff <= '0';
shiftingChar <= waitingChar_r;
shiftingPixels <= waitingPixels_r;