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C64: [VIC2] Fix sprite shift register behavior

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This commit is contained in:
Gyorgy Szombathelyi
2020-04-27 00:35:41 +02:00
parent 34e3f0eb2b
commit 57250c229d
1 changed files with 32 additions and 28 deletions
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60
cores/c64/rtl/video_vicII_656x_a.vhd
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@@ -1122,11 +1122,14 @@ calcBitmap: process(clk)
if phi = '0'
and enaData = '1' then
MCBase <= MCBase_Next;
MDMA <= MDMA_Next;
MYE_ff <= MYE_ff_Next;
MCnt <= MCnt_Next;
MActive <= MActive_Next;
MCBase <= MCBase_Next;
MDMA <= MDMA_Next;
MYE_ff <= MYE_ff_Next;
MCnt <= MCnt_Next;
end if;
if phi = '1'
and enaPixel = '1' then
MActive <= MActive_Next;
end if;
-- 5. If the DMA for a sprite is turned on, three s-accesses are done in
@@ -1156,15 +1159,12 @@ calcBitmap: process(clk)
if rising_edge(clk) then
if enaPixel = '1' then
for i in 0 to 7 loop
--if MPixels(i) = 0 then
--MShift(i) <= false;
--end if;
-- Enable sprites on the correct X position
if MActive_next(i) and rasterXDelay = MX(i) then
if MActive(i) and rasterXDelay = MX(i) then
MShift(i) <= true;
end if;
-- Stop shifting in the s cycles
if (sprite = i and ((vicCycle = cycleSpriteA and phi = '1') or vicCycle = cycleSpriteB)) then
-- Stop shifting in the third s cycle
if sprite = i and phi = '1' and vicCycle = cycleSpriteB then
MShift(i) <= false;
end if;
end loop;
@@ -1177,8 +1177,14 @@ calcBitmap: process(clk)
MC_ff(i) <= (not MC_ff(i)) and MC(i);
if MC_ff(i) = '0' then
MCurrentPixel(i) <= MPixels(i)(23 downto 22);
if MPixels(i) = 0 then
MShift(i) <= false;
end if;
end if;
-- Don't shift in the s cycles (sprite0move.prg, demusinterruptus.prg)
if not (sprite = i and ((vicCycle = cycleSpriteA and phi = '1') or vicCycle = cycleSpriteB)) then
MPixels(i) <= MPixels(i)(22 downto 0) & '0';
end if;
MPixels(i) <= MPixels(i)(22 downto 0) & '0';
end if;
else
MXE_ff(i) <= '0';
@@ -1201,23 +1207,21 @@ calcBitmap: process(clk)
end if;
--
-- Fill Sprite shift-register with new data.
-- Fill Sprite shift-register with new data (even if the sprite is not active)
if enaData = '1' then
if Mactive_Next(to_integer(sprite)) then
case vicCycle is
when cycleSpriteA =>
if phi = '1' then
MPixelStore(15 downto 8) <= di;
end if;
when cycleSpriteB =>
if phi = '0' then
MPixelStore(7 downto 0) <= di;
else
MPixels(to_integer(sprite)) <= MPixelStore & di;
end if;
when others => null;
end case;
end if;
case vicCycle is
when cycleSpriteA =>
if phi = '1' then
MPixelStore(15 downto 8) <= di;
end if;
when cycleSpriteB =>
if phi = '0' then
MPixelStore(7 downto 0) <= di;
else
MPixels(to_integer(sprite)) <= MPixelStore & di;
end if;
when others => null;
end case;
end if;
end if;
end process;