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-rw-r--r--tb/vga.impl.hpp420
1 files changed, 0 insertions, 420 deletions
diff --git a/tb/vga.impl.hpp b/tb/vga.impl.hpp
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--- a/tb/vga.impl.hpp
+++ /dev/null
@@ -1,420 +0,0 @@
-#ifndef TALLER_VGA_IMPL_HPP
-#define TALLER_VGA_IMPL_HPP
-
-#include <array>
-#include <cassert>
-#include <cmath>
-#include <cstdio>
-#include <cstdio>
-
-#include <SDL2/SDL.h>
-#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
- constexpr std::array<taller::vga::video_mode, 13> MODES
- {{
- {25'175'000, { 640, 16, 96, 48}, {480, 11, 2, 31}},
- {31'500'000, { 640, 24, 40, 128}, {480, 9, 3, 28}},
- {31'500'000, { 640, 16, 96, 48}, {480, 11, 2, 32}},
- {36'000'000, { 640, 32, 48, 112}, {480, 1, 3, 25}},
- {38'100'000, { 800, 32, 128, 128}, {600, 1, 4, 14}},
- {40'000'000, { 800, 40, 128, 88}, {600, 1, 4, 23}},
- {50'000'000, { 800, 56, 120, 64}, {600, 37, 6, 23}},
- {49'500'000, { 800, 16, 80, 160}, {600, 1, 2, 21}},
- {56'250'000, { 800, 32, 64, 152}, {600, 1, 3, 27}},
- {65'000'000, {1024, 24, 136, 160}, {768, 3, 6, 29}},
- {75'000'000, {1024, 24, 136, 144}, {768, 3, 6, 29}},
- {78'750'000, {1024, 16, 96, 176}, {768, 1, 3, 28}},
- {94'500'000, {1024, 48, 96, 208}, {768, 1, 3, 36}}
- }};
-}
-
-namespace taller::vga
-{
- template<class 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;
- }
- }
-
- template<class Crtc>
- display<Crtc>::~display() noexcept
- {
- mode = nullptr;
- update_window();
- }
-
- template<class Crtc>
- 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)
- {
- return;
- }
-
- put_pixel();
- move_pos();
- scan_syncs();
-
- last_hsync = crtc.vga_hsync;
- last_vsync = crtc.vga_vsync;
-
- ::SDL_Event event;
- while(::SDL_PollEvent(&event))
- {
- bool value;
- switch(event.type)
- {
- case SDL_KEYDOWN:
- value = false;
- break;
-
- case SDL_KEYUP:
- value = true;
- break;
-
- default:
- continue;
- }
-
- std::size_t index;
- switch(event.key.keysym.sym)
- {
- case SDLK_1:
- index = 0;
- break;
-
- case SDLK_2:
- index = 1;
- break;
-
- case SDLK_3:
- index = 2;
- break;
-
- case SDLK_4:
- index = 3;
- break;
-
- default:
- continue;
- }
-
- keys[index] = value;
- }
- }
-
- template<class Crtc>
- void display<Crtc>::move_pos() noexcept
- {
- if(!mode)
- {
- if(found_line && ++col >= hsync_lo + hsync_hi)
- {
- col = 0;
- }
-
- return;
- }
-
- auto dots = mode->h.active + mode->h.front_porch + mode->h.sync + mode->h.back_porch;
- auto lines = mode->v.active + mode->v.front_porch + mode->v.sync + mode->v.back_porch;
-
- if((col + 1 != mode->h.sync || (!last_hsync && crtc.vga_hsync)) && ++col >= dots)
- {
- col = 0;
- if(row + 1 != mode->v.sync && ++row >= lines)
- {
- row = 0;
- }
- }
-
- if(!last_vsync && crtc.vga_vsync)
- {
- ++row;
- if(window)
- {
- ::SDL_UpdateWindowSurface(window);
- }
- }
- }
-
- template<class Crtc>
- void display<Crtc>::scan_syncs() noexcept
- {
- if(hsync_lo == 0)
- {
- hsync_lo += last_hsync && !crtc.vga_hsync;
- } else if(hsync_hi == 0)
- {
- if(crtc.vga_hsync)
- {
- scan_vsync();
- } else
- {
- ++hsync_lo;
- }
- } else
- {
- scan_vsync();
- }
- }
-
- template<class Crtc>
- void display<Crtc>::scan_vsync() noexcept
- {
- if(found_line && crtc.vga_hsync != (col >= hsync_lo))
- {
- signal_lost();
- } else if(!found_line)
- {
- if(crtc.vga_hsync)
- {
- ++hsync_hi;
- } else
- {
- found_line = true;
- }
- } else if(vsync_lo == 0)
- {
- vsync_lo += last_vsync && !crtc.vga_vsync;
- } else if(last_hsync && !crtc.vga_hsync)
- {
- if(crtc.vga_vsync)
- {
- ++vsync_hi;
- } else if(vsync_hi == 0)
- {
- ++vsync_lo;
- } else
- {
- guess_mode();
-
- hsync_lo = hsync_hi = vsync_lo = vsync_hi = 0;
- found_line = false;
-
- scan_syncs();
- }
- }
- }
-
- template<class Crtc>
- void display<Crtc>::put_pixel() noexcept
- {
- if(!mode)
- {
- return;
- }
-
- auto start_h = mode->h.sync + mode->h.back_porch;
- auto start_v = mode->v.sync + mode->v.back_porch;
-
- if(col < start_h
- || col >= start_h + mode->h.active
- || row < start_v
- || row >= start_v + mode->v.active)
- {
- return;
- }
-
- auto *surface = window ? ::SDL_GetWindowSurface(window) : nullptr;
- if(!window || !surface)
- {
- return;
- }
-
- assert(surface->format->format == SDL_PIXELFORMAT_RGB888);
-
- auto *pixels = static_cast<std::uint32_t*>(surface->pixels);
- auto *pixel = pixels + (row - start_v) * mode->h.active + (col - start_h);
- *pixel = (crtc.vga_r & 0xff) << 16 | (crtc.vga_g & 0xff) << 8 | (crtc.vga_b & 0xff);
- }
-
- template<class Crtc>
- void display<Crtc>::guess_mode() noexcept
- {
- auto timings_match = [this](const video_mode &candidate)
- {
- int dots = candidate.h.active + candidate.h.front_porch + candidate.h.back_porch;
- int lines = candidate.v.active + candidate.v.front_porch + candidate.v.back_porch;
-
- return std::abs(dots - static_cast<int>(hsync_hi)) <= 2
- && std::abs(lines - static_cast<int>(vsync_hi)) <= 2
- && std::abs(static_cast<int>(hsync_lo) - static_cast<int>(candidate.h.sync)) <= 2
- && std::abs(static_cast<int>(vsync_lo) - static_cast<int>(candidate.v.sync)) <= 2;
- };
-
- if(mode != nullptr && timings_match(*mode))
- {
- return;
- }
-
- std::fprintf
- (
- stderr,
- "[vga] hsync_duty: %u/%u, vsync_duty: %u/%u, pixel_clk: %.2fMHz\n",
- hsync_lo,
- hsync_lo + hsync_hi,
- vsync_lo,
- vsync_lo + vsync_hi,
- clock_hz / 1e6
- );
-
- mode = nullptr;
- for(const auto &candidate : MODES)
- {
- if(!timings_match(candidate))
- {
- continue;
- }
-
- float actual_clk_f = clock_hz;
- float expected_clk_f = candidate.pixel_clk;
-
- if(std::fabs((expected_clk_f - actual_clk_f) / expected_clk_f) < 0.02)
- {
- mode = &candidate;
- break;
- }
- }
-
- if(mode)
- {
- auto width = mode->h.active + mode->h.front_porch + mode->h.sync + mode->h.back_porch;
- auto height = mode->v.active + mode->v.front_porch + mode->v.sync + mode->v.back_porch;
- auto rate = static_cast<float>(clock_hz) / (width * height);
-
- std::fprintf
- (
- stderr,
- "[vga] %ux%u @ %.2fHz\n",
- mode->h.active,
- mode->v.active,
- rate
- );
- } else
- {
- std::fputs("[vga] failed to guess mode from timings\n", stderr);
- }
-
- update_window();
- if(mode && window)
- {
- ::SDL_SetWindowSize(window, mode->h.active, mode->v.active);
- }
- }
-
- template<class Crtc>
- void display<Crtc>::signal_lost() noexcept
- {
- if(mode)
- {
- std::fputs("[vga] no signal\n", stderr);
- mode = nullptr;
- }
-
- row = col = 0;
- hsync_lo = hsync_hi = vsync_lo = vsync_hi = 0;
- found_line = false;
-
- update_window();
- }
-
- template<class Crtc>
- void display<Crtc>::update_window() noexcept
- {
- if(!mode && window)
- {
- ::SDL_DestroyWindow(window);
- window = nullptr;
- } else if(mode && !window)
- {
- if(!SDL_WasInit(SDL_INIT_VIDEO))
- {
- ::SDL_SetHint(SDL_HINT_NO_SIGNAL_HANDLERS, "1");
- assert(::SDL_Init(SDL_INIT_VIDEO) >= 0);
- }
-
- window = ::SDL_CreateWindow
- (
- "VGA Display",
- SDL_WINDOWPOS_CENTERED,
- SDL_WINDOWPOS_CENTERED,
- mode->h.active,
- mode->v.active,
- 0
- );
-
- assert(window);
- }
- }
-}
-
-#endif
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