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C64: [VIC2] change sprite counters as in the VIC-II Addendum

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This commit is contained in:
Gyorgy Szombathelyi
2020-04-01 20:10:18 +02:00
parent d511600ad5
commit b6082dd6fc
1 changed files with 24 additions and 29 deletions
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53
cores/c64/rtl/video_vicII_656x_a.vhd
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@@ -974,7 +974,7 @@ calcBitmap: process(clk)
-- Y expansion flipflop
-- -----------------------------------------------------------------------
process(rasterX, rasterY, MDMA, MCnt, MCBase, MActive, MYE_ff, ME, MY, MYE, vicCycle, sprite)
process(rasterX, rasterY, MDMA, MCnt, MCBase, MCBase_next, MActive, MYE_ff, ME, MY, MYE, vicCycle, sprite)
begin
MCBase_next <= MCBase;
MDMA_next <= MDMA;
@@ -992,36 +992,24 @@ calcBitmap: process(clk)
case vicCycle is
when cycleRefresh5 =>
-- 7. In the first phase of cycle 15, it is checked if the expansion flip flop
-- is set. If so, MCBASE is incremented by 2.
for i in 0 to 7 loop
if MDMA(i) and MYE_ff(i) = '1' then
MCBase_next(i) <= MCBase(i) + 2;
end if;
end loop;
when cycleChar =>
-- 8. In the first phase of cycle 16, it is checked if the expansion flip flop
-- is set. If so, MCBASE is incremented by 1. After that, the VIC checks if
-- MCBASE is equal to 63 and turns of the DMA and the display of the sprite if it is.
-- 7. In the first phase of cycle 16, it is checked if the expansion flip flop
-- is set. If so, MCBASE load from MC (MC->MCBASE), unless the CPU cleared
-- the Y expansion bit in $d017 in the second phase of cycle 15, in which case
-- MCBASE is set to X = (101010 & (MCBASE & MC)) | (010101 & (MCBASE | MC)).
-- After the MCBASE update, the VIC checks if MCBASE is equal to 63 and turns
-- off the DMA of the sprite if it is. (VIC Addendum)
if rasterX(9 downto 3) = "0000010" then
for i in 0 to 7 loop
if MDMA(i) then
if MYE_ff(i) = '1' then
MCBase_next(i) <= MCBase(i) + 1;
if MCBase(i) = 62 then
MDMA_next(i) <= false;
MActive_next(i) <= false;
end if;
else
if MYE(i) = '0' then
-- this is from debugging Robocop fixed cart intro
MCBase_next(i) <= MCBase(i) - 1;
elsif MCBASE(i) = 63 then
MDMA_next(i) <= false;
MActive_next(i) <= false;
end if;
MCBase_next(i) <= MCnt(i);
elsif MYE(i) = '0' then
-- MYE just turned off
MCBase_next(i) <= ("101010" and (MCBase(i) and MCnt(i))) or ("010101" and (MCBase(i) or MCnt(i)));
end if;
if MCBase_next(i) = 63 then
MDMA_next(i) <= false;
end if;
end if;
end loop;
@@ -1061,11 +1049,18 @@ calcBitmap: process(clk)
-- sprite is turned on and the Y coordinate of the sprite matches the lower
-- 8 bits of RASTER. If this is the case, the display of the sprite is
-- turned on.
-- VIC Addendum: the actual disabling of sprite display is likely handled
-- during the first phase of cycle 58 (see rule 4).
if sprite = "000" then
for i in 0 to 7 loop
MCnt_Next(i) <= MCBase(i);
if MDMA(i) and ME(i) = '1' and rasterY(7 downto 0) = MY(i) then
MActive_Next(i) <= true;
if MDMA(i) then
if ME(i) = '1' and rasterY(7 downto 0) = MY(i) then
MActive_Next(i) <= true;
end if;
else
MActive_next(i) <= false;
end if;
end loop;
end if;
@@ -1097,7 +1092,7 @@ calcBitmap: process(clk)
-- MC is incremented by one after each s-access.
if enaData = '1' then
if (vicCycle = cycleSpriteA and phi = '1')
or (vicCycle = cycleSpriteB and phi = '0') then
or (vicCycle = cycleSpriteB) then
if MDMA(to_integer(sprite)) then
MCnt(to_integer(sprite)) <= MCnt(to_integer(sprite)) + 1;
end if;