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C64: [VIC2] implement border flip-flops

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Passes border open timing VICE tests in PAL mode
Seems the pixel generator outputs wrong colors in open borders
This commit is contained in:
Gyorgy Szombathelyi
2020-03-20 10:58:15 +01:00
parent 08fdc65d69
commit 11679a3e2b
1 changed files with 50 additions and 38 deletions
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88
cores/c64/rtl/video_vicII_656x_a.vhd
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@@ -98,8 +98,9 @@ architecture rtl of video_vicii_656x is
signal spriteColors: spriteColorsDef;
-- borders and blanking
signal LRBorder: std_logic;
signal MainBorder: std_logic;
signal TBBorder: std_logic;
signal setTBBorder: boolean;
signal hBlack: std_logic;
signal vBlanking : std_logic;
signal hBlanking : std_logic;
@@ -136,6 +137,8 @@ architecture rtl of video_vicii_656x is
-- Raster counters
signal rasterX : unsigned(9 downto 0) := (others => '0');
signal rasterY : unsigned(8 downto 0) := (others => '0');
signal rasterY_next : unsigned(8 downto 0);
signal cycleLast : boolean;
-- Light pen
signal lightPenHit: std_logic;
@@ -643,6 +646,9 @@ vicStateMachine: process(clk)
-- -----------------------------------------------------------------------
-- X/Y Raster counter
-- -----------------------------------------------------------------------
cycleLast <= (vicCycle = cycleSpriteB) and (sprite = 2);
rasterY_next <= (others => '0') when lastLineFlag else RasterY + 1;
rasterCounters: process(clk)
begin
if rising_edge(clk) then
@@ -661,12 +667,8 @@ rasterCounters: process(clk)
if phi = '1'
and enaData = '1'
and baSync = '0' then
if (vicCycle = cycleSpriteB)
and (sprite = 2) then
rasterY <= rasterY + 1;
if lastLineFlag then
rasterY <= (others => '0');
end if;
if cycleLast then
rasterY <= rasterY_next;
end if;
end if;
end if;
@@ -780,48 +782,58 @@ doHBlanking: process(clk)
-- Borders
-- -----------------------------------------------------------------------
calcBorders: process(clk)
variable newTBBorder: std_logic;
variable newTBBorder: std_logic;
begin
if rising_edge(clk) then
if enaPixel = '1' then
--
-- Calc top/bottom border
newTBBorder := TBBorder;
-- if (rasterY = 55) and (RSEL = '0') and (rasterEnable = '1') then
if (rasterY = 55) and (rasterEnable = '1') then
-- 1. If the X coordinate reaches the right comparison value, the main border
-- flip flop is set.
if (rasterX = (335+1) and CSEL = '0') or (rasterX = (344+1) and CSEL = '1') then
MainBorder <= '1';
end if;
-- 2. If the Y coordinate reaches the bottom comparison value in cycle 63, the
-- vertical border flip flop is set. FIX: compare during the whole line, but set at cycle 63
-- 3. If the Y coordinate reaches the top comparison value in cycle 63 and the
-- DEN bit in register $d011 is set, the vertical border flip flop is
-- reset. FIX: compare during the whole line and act immediately
if (rasterY = 247 and RSEL = '0') or (rasterY = 251 and RSEL = '1') then
setTBBorder <= true;
end if;
if ((rasterY = 55 and RSEL = '0') or (rasterY = 51 and RSEL = '1')) and DEN = '1' then
newTBBorder := '0';
end if;
if (rasterY = 51) and (RSEL = '1') and (rasterEnable = '1') then
newTBBorder := '0';
if cycleLast then
if setTBBorder then
newTBBorder := '1';
setTBBorder <= false;
end if;
end if;
if (rasterY = 247) and (RSEL = '0') then
newTBBorder := '1';
end if;
if (rasterY = 251) and (RSEL = '1') then
newTBBorder := '1';
end if;
--
-- Calc left/right border
if (rasterX = (31+1)) and (CSEL = '0') then
LRBorder <= newTBBorder;
TBBorder <= newTBBorder;
end if;
if (rasterX = (24+1)) and (CSEL = '1') then
LRBorder <= newTBBorder;
TBBorder <= newTBBorder;
end if;
if (rasterX = (335+1)) and (CSEL = '0') then
LRBorder <= '1';
end if;
if (rasterX = (344+1)) and (CSEL = '1') then
LRBorder <= '1';
if (rasterX = (31+1) and CSEL = '0') or (rasterX = (24+1) and CSEL = '1') then
-- 4. If the X coordinate reaches the left comparison value and the Y
-- coordinate reaches the bottom one, the vertical border flip flop is set.
-- FIX: act on the already triggered condition
if setTBBorder then
newTBBorder := '1';
setTBBorder <= false;
end if;
-- 5. If the X coordinate reaches the left comparison value and the Y
-- coordinate reaches the top one and the DEN bit in register $d011 is set,
-- the vertical border flip flop is reset.
if ((rasterY = 55 and RSEL = '0') or (rasterY = 51 and RSEL = '1')) and DEN = '1' then
newTBBorder := '0';
end if;
-- 6. If the X coordinate reaches the left comparison value and the vertical
-- border flip flop is not set, the main flip flop is reset.
if newTBBorder = '0' and setTBBorder = false then
MainBorder <= '0';
end if;
end if;
TBBorder <= newTBBorder;
end if;
end if;
end process;
-- -----------------------------------------------------------------------
-- Pixel generator for Text/Bitmap screen
-- -----------------------------------------------------------------------
@@ -1139,7 +1151,7 @@ calcBitmap: process(clk)
-- if (cs = '1' and aRegisters = "011100") then
-- colorIndex <= "1111";
-- end if;
if (LRBorder = '1') or (TBBorder = '1') then
if MainBorder = '1' then
colorIndex <= EC;
end if;
if (hBlack = '1') then