Added header for OS drawing and a double buffer.

bastl/include/algorithm

@@ -6,7 +6,17 @@
 
 namespace std
 {
+template<typename T>
+constexpr const T& min(const T& left, const T& right)
+{
+    return right < left ? right : left;
+}
 
+template<typename T>
+constexpr const T& max(const T& left, const T& right)
+{
+    return right > left ? right : left;
+}
 }
 
 #endif // !defined(BAD_APPLE_OS_ALGORITHM_INCLUDED)

targets/_any/SConscript

@@ -3,6 +3,7 @@ Import('env')
 any_target_sources = Split('''
     src/app/main.cpp
 
+    src/os/draw.cpp
     src/os/panic.cpp
     src/os/tty.cpp
 

targets/_any/include/os/draw.hpp

@@ -0,0 +1,69 @@
+
+#pragma once
+
+#if !defined(BAD_APPLE_OS_DRAW_HPP_INCLUDED)
+#define BAD_APPLE_OS_DRAW_HPP_INCLUDED
+
+#include <stdint.h>
+#include <vector>
+
+namespace draw
+{
+const unsigned SIZE_FULL = static_cast<unsigned>(-1);
+
+struct Pixel
+{
+    uint8_t blue = 0;
+    uint8_t green = 0;
+    uint8_t red = 0;
+    uint8_t reserved_ = 0;
+};
+
+class Framebuffer
+{
+protected:
+    Pixel* mBase = nullptr;
+    unsigned mWidth = 0;
+    unsigned mHeight = 0;
+    unsigned mPitch = 0;
+public:
+    Framebuffer() = default;
+    Framebuffer(const Framebuffer&) = default;
+    Framebuffer(Pixel* base, unsigned width, unsigned height, unsigned pitch) noexcept
+        : mBase(base), mWidth(width), mHeight(height), mPitch(pitch) {}
+
+    [[nodiscard]] Pixel* getBase() const noexcept { return mBase; }
+    [[nodiscard]] unsigned getWidth() const noexcept { return mWidth; }
+    [[nodiscard]] unsigned getHeight() const noexcept { return mHeight; }
+    [[nodiscard]] unsigned getPitch() const noexcept { return mPitch; }
+    [[nodiscard]] unsigned getBufferSize() const noexcept { return mPitch * mHeight * sizeof(Pixel); }
+
+    void setPixel(unsigned posX, unsigned posY, Pixel pixel) noexcept;
+};
+
+class OwningFramebuffer : public Framebuffer
+{
+private:
+    std::vector<Pixel> mPixels;
+public:
+    OwningFramebuffer() = default;
+    OwningFramebuffer(const OwningFramebuffer&) noexcept = default;
+    OwningFramebuffer(OwningFramebuffer&&) noexcept = default;
+    OwningFramebuffer(unsigned width, unsigned height, unsigned pitch) noexcept;
+
+    OwningFramebuffer& operator=(const OwningFramebuffer&) noexcept = default;
+    OwningFramebuffer& operator=(OwningFramebuffer&&) noexcept = default;
+
+    static OwningFramebuffer makeFrom(const Framebuffer& other) noexcept
+    {
+        return OwningFramebuffer(other.getWidth(), other.getHeight(), other.getPitch());
+    }
+};
+
+void initializeDefaultFramebuffer(const Framebuffer& framebuffer) noexcept;
+void setPixelDirect(unsigned posX, unsigned posY, Pixel pixel) noexcept;
+void setPixel(unsigned posX, unsigned posY, Pixel pixel) noexcept;
+void flushPixels() noexcept;
+}
+
+#endif // !defined(BAD_APPLE_OS_FRAMEBUFFER_HPP_INCLUDED)

targets/_any/src/cstdlib/stdlib.cpp

@@ -106,4 +106,15 @@ void free(void* memory) noexcept
     block->nextBlock = gNextBlock;
     gNextBlock = block;
 }
+
+int __cxa_atexit(void (*func)(void*), void* arg, void* dsoHandle)
+{
+    (void) func;
+    (void) arg;
+    (void) dsoHandle;
+
+    // NOOP for now
+    // TODO
+    return 0;
+}
 } // extern "C"

targets/_any/src/os/draw.cpp

@@ -0,0 +1,52 @@
+
+#include "os/draw.hpp"
+
+#include <cstring>
+
+namespace draw
+{
+namespace
+{
+Framebuffer gFramebuffer;
+OwningFramebuffer gDoubleBuffer;
+}
+
+OwningFramebuffer::OwningFramebuffer(unsigned width, unsigned height, unsigned pitch) noexcept
+    : Framebuffer(nullptr, width, height, pitch)
+{
+    mPixels.resize(height * pitch);
+    mBase = mPixels.data();
+}
+
+void Framebuffer::setPixel(unsigned int posX, unsigned int posY, Pixel pixel) noexcept
+{
+    if (posX >= mWidth || posY > mHeight) {
+        return;
+    }
+    mBase[posY * mPitch + posX] = pixel;
+}
+
+
+void initializeDefaultFramebuffer(const Framebuffer& framebuffer) noexcept
+{
+    gFramebuffer = framebuffer;
+    gDoubleBuffer = OwningFramebuffer::makeFrom(gFramebuffer);
+}
+
+void setPixelDirect(unsigned posX, unsigned posY, Pixel pixel) noexcept
+{
+    gFramebuffer.setPixel(posX, posY, pixel);
+    // also set it in the double buffer, otherwise it will be lost on flush
+    gDoubleBuffer.setPixel(posX, posY, pixel);
+}
+
+void setPixel(unsigned posX, unsigned posY, Pixel pixel) noexcept
+{
+    gDoubleBuffer.setPixel(posX, posY, pixel);
+}
+
+void flushPixels() noexcept
+{
+    std::memcpy(gFramebuffer.getBase(), gDoubleBuffer.getBase(), gFramebuffer.getBufferSize());
+}
+}

targets/x86_64/src/kernel/startup.cpp

@@ -1,16 +1,41 @@
 
-#include "os/tty.hpp"
-
 #include <cstdio>
-#include <cstdlib>
 #include "boot.hpp"
 
+#include "os/draw.hpp"
+#include "os/tty.hpp"
+
 extern "C" int gKernelEnd;
 
 namespace
 {
 void initHeapFromEfiMemoryMap(const EfiMemoryMap& memoryMap) noexcept
 {
+    const uint64_t minAddr = reinterpret_cast<uint64_t>(&gKernelEnd);
+    for (const EFI_MEMORY_DESCRIPTOR& descriptor : memoryMap)
+    {
+        // TODO: what about other types?
+        if (descriptor.Type != EfiConventionalMemory)
+        {
+            continue;
+        }
+
+        uint64_t addr = descriptor.PhysicalStart;
+        uint64_t len = descriptor.NumberOfPages * 4096; // TODO: is this the correct page size?
+        // anything before the kernel we ignore
+        if (addr < minAddr)
+        {
+            // if the entire entry is before the kernel, continue
+            if (addr + len <= minAddr)
+            {
+                continue;
+            }
+            // otherwise shrink it and use the rest
+            len -= (minAddr - addr);
+            addr = minAddr;
+        }
+        __ba_registerAllocatableMemory(reinterpret_cast<void*>(addr), len);
+    }
 #if 0
     const uint64_t minAddr = reinterpret_cast<uint64_t>(&gKernelEnd);
     for (uint32_t addr = firstEntryAddr; addr < firstEntryAddr + bufferLength;)
@@ -71,35 +96,34 @@ void kernel_main()
 {
     initGlobals();
 
-	/* Initialize terminal interface */
-	tty::initialize();
+    // init the heap (required for the double buffer)
+    initHeapFromEfiMemoryMap(gBootInfo->memoryMap);
 
-    std::printf("Kernel End: %p\n", &gKernelEnd);
+    // initialize the framebuffer
+    draw::initializeDefaultFramebuffer({
+        /* base   = */ static_cast<draw::Pixel*>(gBootInfo->displayInfo.frameBufferBase),
+        /* width  = */ gBootInfo->displayInfo.frameBufferWidth,
+        /* height = */ gBootInfo->displayInfo.frameBufferHeight,
+        /* pitch  = */ gBootInfo->displayInfo.frameBufferPitch / 4
+    });
+
+	// initialize terminal interface
+	// tty::initialize();
+
+    // std::printf("Kernel End: %p\n", &gKernelEnd);
 
-    struct Pixel
-    {
-        uint8_t blue = 0;
-        uint8_t green = 0;
-        uint8_t red = 0;
-        uint8_t reserved = 0;
-    };
-    auto setPixel = [](unsigned x, unsigned y, Pixel color)
-    {
-        Pixel* framebuffer = static_cast<Pixel*>(gBootInfo->displayInfo.frameBufferBase);
-        framebuffer[y * gBootInfo->displayInfo.frameBufferPitch / 4 + x] = color;
-    };
     for (int x = 0; x < 100; ++x)
     {
         for (int y = 0; y < 100; ++y)
         {
-            setPixel(x, y, {.red = 255});
+            draw::setPixel(x, y, {.red = 255});
         }
     }
+    draw::flushPixels();
 
     /* Initialize the heap */
     // assert(gMultibootHeader->flags & MULTIBOOT_INFO_MEM_MAP);
     // initHeapFromMultibootHeader(gMultibootHeader->mmap_addr, gMultibootHeader->mmap_length);
-    initHeapFromEfiMemoryMap(gBootInfo->memoryMap);
 
     main();