Implement fast video

5 files changed, 109 insertions, 16 deletions

diff --git a/sim/sim.py b/sim/sim.py
index dceabb4..4a1dfa8 100755
--- a/sim/sim.py
+++ b/sim/sim.py
@@ -342,7 +342,7 @@ do_output = module_get('do_output')
 if init := module_get('init'):
     init()
 
-exec_args = [verilated, '--headless', '--dump-regs']
+exec_args = [verilated, '--dump-regs']
 
 cycles = module_get('cycles', 1024)
 if cycles is not None:
@@ -351,6 +351,9 @@ if cycles is not None:
 if not module_get('enable_tty', False):
     exec_args.append('--no-tty')
 
+if not module_get('enable_video', False):
+    exec_args.append('--headless')
+
 for rng in mem_dumps:
     length = rng.stop - rng.start
     assert rng.start >= 0 and rng.stop > rng.start \
diff --git a/tb/sim/descifrador.py b/tb/sim/descifrador.py
index e754f2a..a77375b 100644
--- a/tb/sim/descifrador.py
+++ b/tb/sim/descifrador.py
@@ -7,6 +7,7 @@ loads = {START: FILE}
 consts = {0x30050000: 1, 0x30060000: 0}
 cycles = 23000000
 mem_dumps = [range(START, START + SIZE)]
+enable_video = True
 
 def final():
     words = []
diff --git a/tb/top/conspiracion.cpp b/tb/top/conspiracion.cpp
index f0cfaa2..de43952 100644
--- a/tb/top/conspiracion.cpp
+++ b/tb/top/conspiracion.cpp
@@ -210,6 +210,11 @@ int main(int argc, char **argv)
 		parser, "headless", "Disable video output", {"headless"}
 	);
 
+	args::Flag accurate_video
+	(
+		parser, "accurate-video", "Enable signal-level video emulation", {"accurate-video"}
+	);
+
 	args::Flag no_tty
 	(
 		parser, "no-tty", "Disable TTY takeoveer", {"no-tty"}
@@ -292,16 +297,21 @@ int main(int argc, char **argv)
 		trace.open("trace.vcd");
 	}
 
-	interconnect<Vconspiracion_platform> avl(*top.conspiracion->plat);
-	interconnect<Vconspiracion_vga_domain> avl_vga(*top.conspiracion->plat->vga);
-
 	mem<std::uint32_t> hps_ddr3(0x0000'0000, 512 << 20);
 	jtag_uart ttyJ0(0x3000'0000);
 	interval_timer timer(0x3002'0000);
 	mem<std::uint32_t> vram(0x3800'0000, 64 << 20);
 	null vram_null(0x3800'0000, 64 << 20, 2);
 	window vram_window(vram, 0x0000'0000);
-	display<Vconspiracion_vga_domain> vga(*top.conspiracion->plat->vga, 25'175'000);
+
+	display<Vconspiracion_vga_domain> vga
+	(
+		*top.conspiracion->plat->vga,
+		0x3800'0000, 25'175'000, 50'000'000
+	);
+
+	interconnect<Vconspiracion_platform> avl(*top.conspiracion->plat);
+	interconnect<Vconspiracion_vga_domain> avl_vga(*top.conspiracion->plat->vga);
 
 	std::vector<const_map> consts;
 	for(const auto &init : *const_)
@@ -309,7 +319,8 @@ int main(int argc, char **argv)
 		consts.emplace_back(init.addr, init.value);
 	}
 
-	bool enable_video = !headless;
+	bool enable_fast_video = !headless && !accurate_video;
+	bool enable_accurate_video = !headless && accurate_video;
 
 	avl.attach(hps_ddr3);
 	avl.attach(ttyJ0);
@@ -320,7 +331,10 @@ int main(int argc, char **argv)
 		avl.attach(slave);
 	}
 
-	if(enable_video)
+	if(enable_fast_video)
+	{
+		avl.attach(vga);
+	} else if(enable_accurate_video)
 	{
 		avl.attach(vram);
 		avl_vga.attach(vram_window);
@@ -382,14 +396,14 @@ int main(int argc, char **argv)
 			failed = true;
 		}
 
-		if(enable_video)
+		if(enable_accurate_video)
 		{
 			if(!avl_vga.tick(top.clk_clk))
 			{
 				failed = true;
 			}
 
-			vga.tick(top.clk_clk);
+			vga.signal_tick(top.clk_clk);
 		}
 
 		if(enable_trace)
diff --git a/tb/vga.hpp b/tb/vga.hpp
index 92446ca..578dd17 100644
--- a/tb/vga.hpp
+++ b/tb/vga.hpp
@@ -8,6 +8,8 @@
 #include <SDL2/SDL_surface.h>
 #include <SDL2/SDL_video.h>
 
+#include "avalon.hpp"
+
 namespace taller::vga
 {
 	struct timings
@@ -26,14 +28,19 @@ namespace taller::vga
 	};
 
 	template<class Crtc>
-	class display
+	class display : public avalon::slave
 	{
 		public:
-			display(Crtc &crtc, std::uint32_t clock_hz) noexcept;
+			display(Crtc &crtc, std::uint32_t base, std::uint32_t clock_hz, std::uint32_t bus_hz = 0) noexcept;
 
 			~display() noexcept;
 
-			void tick(bool clk) noexcept;
+			virtual void tick() noexcept final override;
+
+			virtual bool read(std::uint32_t addr, std::uint32_t &data) noexcept final override;
+			virtual bool write(std::uint32_t addr, std::uint32_t data, unsigned byte_enable) noexcept final override;
+
+			void signal_tick(bool clk) noexcept;
 
 			inline bool key(std::size_t index)
 			{
@@ -41,6 +48,9 @@ namespace taller::vga
 			}
 
 		private:
+			unsigned            ticks         = 0;
+			unsigned            refresh_ticks = 0;
+			unsigned            max_addr      = 0;
 			Crtc&               crtc;
 			SDL_Window         *window     = nullptr;
 			const video_mode   *mode       = nullptr;
diff --git a/tb/vga.impl.hpp b/tb/vga.impl.hpp
index 9c3294c..988259a 100644
--- a/tb/vga.impl.hpp
+++ b/tb/vga.impl.hpp
@@ -11,6 +11,8 @@
 #include <SDL2/SDL_surface.h>
 #include <SDL2/SDL_video.h>
 
+#include "avalon.hpp"
+
 namespace
 {
 	// https://web.mit.edu/6.111/www/s2004/NEWKIT/vga.shtml
@@ -35,10 +37,26 @@ namespace
 namespace taller::vga
 {
 	template<class Crtc>
-	display<Crtc>::display(Crtc &crtc, std::uint32_t clock_hz) noexcept
-	: crtc(crtc),
+	display<Crtc>::display(Crtc &crtc, std::uint32_t base, std::uint32_t clock_hz, std::uint32_t bus_hz) noexcept
+	: avalon::slave(base, 64 << 20, 4),
+	  crtc(crtc),
 	  clock_hz(clock_hz)
-	{}
+	{
+		if(bus_hz > 0)
+		{
+			mode = &MODES[0];
+			max_addr = mode->h.active * mode->v.active;
+
+			refresh_ticks =
+				static_cast<float>(bus_hz)
+				/ mode->pixel_clk
+				* (mode->h.active + mode->h.front_porch + mode->h.sync + mode->h.back_porch)
+				* (mode->v.active + mode->v.front_porch + mode->v.sync + mode->v.back_porch);
+
+			ticks = refresh_ticks - 1;
+			update_window();
+		}
+	}
 
 	template<class Crtc>
 	display<Crtc>::~display() noexcept
@@ -48,7 +66,54 @@ namespace taller::vga
 	}
 
 	template<class Crtc>
-	void display<Crtc>::tick(bool clk) noexcept
+	void display<Crtc>::tick() noexcept
+	{
+		if(++ticks == refresh_ticks)
+		{
+			ticks = 0;
+			if(!window)
+			{
+				update_window();
+			}
+
+			if(window)
+			{
+				::SDL_UpdateWindowSurface(window);
+			}
+		}
+	}
+
+	template<class Crtc>
+	bool display<Crtc>::read(std::uint32_t addr, std::uint32_t &data) noexcept
+	{
+		return true;
+	}
+
+	template<class Crtc>
+	bool display<Crtc>::write(std::uint32_t addr, std::uint32_t data, unsigned byte_enable) noexcept
+	{
+		if(!window || !mode)
+		{
+			return true;
+		}
+
+		auto *surface = ::SDL_GetWindowSurface(window);
+		if(!surface)
+		{
+			return true;
+		}
+
+		auto *pixels = static_cast<std::uint32_t*>(surface->pixels);
+		if(addr < max_addr)
+		{
+			pixels[addr] = data;
+		}
+
+		return true;
+	}
+
+	template<class Crtc>
+	void display<Crtc>::signal_tick(bool clk) noexcept
 	{
 		if(!clk)
 		{