progress: ImGui Port - Desktop UI + ImGui rendering performance overhaul

Full ImGui desktop environment (desktop.pas):
- Gradient wallpaper, taskbar with clock, start menu
- Desktop icons with click-to-open
- Windowed apps: System Info, Terminal, File Browser, Task Manager
- Terminal dispatches to registered kernel commands with output capture

Performance: Software rasterizer rewrite (imgui.pas, imgbridge.c)
- Quad detection: merge consecutive triangle pairs into fast rect fills
- 3 new fast-path rect fillers (solid/gradient/textured) using REP STOSD
  and 16.16 fixed-point integer inner loops
- Triangle rasterizer rewritten with fixed-point edge functions
- Back-buffer clear: DrawPixel loop -> REP STOSD (~200x faster)
- Render stat debug counters added

ISR-safe input buffering (imgbridge.c)
- Keyboard/mouse events buffered in lock-free ring buffers from ISR context
- Drained once per frame from main loop to prevent data races

Other changes:
- imguitypes.pas: InputTextFlags renumbered for cimgui 1.91+
- video.pas: backBufferLocation getter added
- kernel.pas: VFS init moved earlier, main loop uses desktop_frame,
  mouse hook uses ISR-safe buffering
- lmemorymanager.pas: kalloc/kfree exported with public aliases for C linkage
- scheduler.pas: Root_Task moved to interface for desktop task manager
- terminal.pas: freeParams exposed in interface

Dockerfile

@@ -5,9 +5,12 @@ VOLUME ["/code"]
 ENV DEBIAN_FRONTEND=noninteractive
 RUN dpkg --add-architecture i386
 RUN apt-get update && apt-get install -y \
-	curl dos2unix wget git make nasm binutils:i386 xorriso grub-pc-bin && \
+	curl dos2unix wget git make nasm binutils xorriso grub-pc-bin \
+	gcc-multilib g++-multilib && \
 	apt-get clean my room
 
+RUN git clone --depth=1 --recurse-submodules https://github.com/cimgui/cimgui.git /cimgui
+
 SHELL ["/bin/bash", "-c"]
 ARG FPC_VERSION=2.6.4
 RUN curl -sL https://sourceforge.net/projects/freepascal/files/Linux/$FPC_VERSION/fpc-$FPC_VERSION.i386-linux.tar/download | tar -xf - && \

compile.sh

@@ -23,6 +23,7 @@ runOrFail() {
 declare -a run_steps=(
 	"compile_stub.sh" "Failed to compile stub!"
 	"compile_vergen.sh" "Versions failed to compile"
+	"compile_imgui.sh" "Failed to compile ImGui!"
 	"compile_sources.sh" "Failed to compile FPC Sources!"
 	"compile_link.sh" "Failed linking!"
 	"compile_isogen.sh" "Failed to create ISO!"

compile_imgui.sh

@@ -0,0 +1,90 @@
+#!/usr/bin/env bash
+echo " "
+echo "======================="
+echo " "
+echo "Compiling ImGui (cimgui)..."
+echo " "
+
+IMGUI_DIR=/cimgui
+IMGUI_SRC=$IMGUI_DIR/imgui
+BRIDGE_SRC=src/driver/video/imgui
+
+# Flags shared by all C/C++ compilation units:
+#   -m32              -> i386 target
+#   -ffreestanding    -> no implicit stdlib inclusion
+#   -fno-builtin      -> don't inline memcpy/memset/etc. so our stubs are used
+#   -O2               -> optimise for speed
+#   -ffunction-sections -fdata-sections -> allow --gc-sections in linker
+C_FLAGS="-m32 -ffreestanding -fno-builtin -O2 -ffunction-sections -fdata-sections"
+
+# Extra flags for C++ translation units (cimgui/imgui sources):
+#   -fno-exceptions         -> no stack-unwinding machinery
+#   -fno-rtti               -> no typeinfo / dynamic_cast
+#   -fno-use-cxa-atexit     -> don't emit __cxa_atexit calls for static dtors
+#   -fno-threadsafe-statics -> no guard-variable emission for local statics
+# NOTE: *not* -ffreestanding / -fno-builtin here — imgui includes <cmath> and
+#       other hosted headers that refuse to compile in freestanding mode.
+#       The object files are archived into a static lib and linked freestanding;
+#       any hosted-stdlib calls (malloc/free/sin/cos/…) resolve to crtshim.c.
+CPP_FLAGS="-m32 -O2 -ffunction-sections -fdata-sections -fno-exceptions -fno-rtti -fno-use-cxa-atexit -fno-threadsafe-statics -fno-stack-protector -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0 -DNDEBUG -DIMGUI_ENABLE_STB_TRUETYPE"
+
+INCLUDE="-I$IMGUI_DIR -I$IMGUI_SRC"
+
+echo "Compiling C runtime shim..."
+gcc $C_FLAGS $INCLUDE \
+    -c $BRIDGE_SRC/crtshim.c \
+    -o lib/imgui_crtshim.o || { echo "Failed: crtshim.c"; exit 1; }
+
+echo "Compiling render bridge..."
+# imgbridge is compiled as C++ so it sees cimgui.h function declarations
+# (C++ mode is required; the .c extension is overridden with -x c++)
+g++ $CPP_FLAGS $INCLUDE \
+    -x c++ \
+    -DCIMGUI_DEFINE_ENUMS_AND_STRUCTS \
+    -c $BRIDGE_SRC/imgbridge.c \
+    -o lib/imgui_bridge.o || { echo "Failed: imgbridge.c"; exit 1; }
+
+echo "Compiling cimgui wrapper..."
+g++ $CPP_FLAGS $INCLUDE \
+    -c $IMGUI_DIR/cimgui.cpp \
+    -o lib/imgui_cimgui.o || { echo "Failed: cimgui.cpp"; exit 1; }
+
+echo "Compiling imgui core..."
+g++ $CPP_FLAGS $INCLUDE \
+    -c $IMGUI_SRC/imgui.cpp \
+    -o lib/imgui_core.o || { echo "Failed: imgui.cpp"; exit 1; }
+
+echo "Compiling imgui draw..."
+g++ $CPP_FLAGS $INCLUDE \
+    -c $IMGUI_SRC/imgui_draw.cpp \
+    -o lib/imgui_draw.o || { echo "Failed: imgui_draw.cpp"; exit 1; }
+
+echo "Compiling imgui tables..."
+g++ $CPP_FLAGS $INCLUDE \
+    -c $IMGUI_SRC/imgui_tables.cpp \
+    -o lib/imgui_tables.o || { echo "Failed: imgui_tables.cpp"; exit 1; }
+
+echo "Compiling imgui widgets..."
+g++ $CPP_FLAGS $INCLUDE \
+    -c $IMGUI_SRC/imgui_widgets.cpp \
+    -o lib/imgui_widgets.o || { echo "Failed: imgui_widgets.cpp"; exit 1; }
+
+echo "Compiling imgui demo..."
+g++ $CPP_FLAGS $INCLUDE \
+    -c $IMGUI_SRC/imgui_demo.cpp \
+    -o lib/imgui_demo.o || { echo "Failed: imgui_demo.cpp"; exit 1; }
+
+echo "Archiving cimgui.a..."
+# NOTE: imgui_bridge.o and imgui_crtshim.o are NOT in the archive because
+# compile_link.sh already picks them up individually via find lib/ -name "*.o".
+# Including them here would cause duplicate symbol errors.
+ar rcs lib/cimgui.a \
+    lib/imgui_cimgui.o \
+    lib/imgui_core.o \
+    lib/imgui_draw.o \
+    lib/imgui_tables.o \
+    lib/imgui_widgets.o \
+    lib/imgui_demo.o || { echo "Failed: ar"; exit 1; }
+
+echo "ImGui compiled successfully."
+exit 0

compile_link.sh

@@ -14,4 +14,6 @@ done;
 objstring=lib/stub.o" "$objstring 
 echo "Object Files: "$objstring
 echo " "
-ld -m elf_i386 -s --gc-sections -Tlinker.script -o bin/kernel.bin $objstring
+LIBGCC=$(gcc -m32 -print-libgcc-file-name)
+ld -m elf_i386 -s --gc-sections -Tlinker.script -o bin/kernel.bin $objstring \
+    --start-group lib/cimgui.a $LIBGCC --end-group

compile_sources.sh

@@ -4,4 +4,4 @@ echo "======================="
 echo " "
 echo "Compiling FPC Sources..."
 echo " "
-fpc -Aelf -gw -g -gl -n -vlewn -O3 -Op3 -Si -Sc -Sg -Xd -CX -XXs -CfSSE -CfSSE2 -Rintel -Pi386 -Tlinux -FElib/ -Fusrc/* -Fusrc/driver/* -Fusrc/driver/net/* src/kernel.pas
+fpc -Aelf -gw -g -gl -n -vlewn -O3 -Op3 -Si -Sc -Sg -Xd -CX -XXs -CfSSE -CfSSE2 -Rintel -Pi386 -Tlinux -FElib/ -Fusrc/* -Fusrc/driver/* -Fusrc/driver/net/* -Fusrc/driver/video/* -Fusrc/driver/video/imgui/* src/kernel.pas

dockerout.txt

@@ -0,0 +1,20 @@
+4023:CIMGUI_API float igGetWindowDpiScale(void);
+4081:CIMGUI_API const ImVec4_c* igGetStyleColorVec4(ImGuiCol idx);
+4082:CIMGUI_API ImVec2_c igGetCursorScreenPos(void);
+4084:CIMGUI_API ImVec2_c igGetContentRegionAvail(void);
+4085:CIMGUI_API ImVec2_c igGetCursorPos(void);
+4086:CIMGUI_API float igGetCursorPosX(void);
+4087:CIMGUI_API float igGetCursorPosY(void);
+4091:CIMGUI_API ImVec2_c igGetCursorStartPos(void);
+4350:CIMGUI_API void igBeginDisabled(bool disabled);
+4372:CIMGUI_API ImVec2_c igGetItemRectMin(void);
+4373:CIMGUI_API ImVec2_c igGetItemRectMax(void);
+4374:CIMGUI_API ImVec2_c igGetItemRectSize(void);
+4377:CIMGUI_API ImDrawList* igGetBackgroundDrawList(ImGuiViewport* viewport);
+4378:CIMGUI_API ImDrawList* igGetForegroundDrawList_ViewportPtr(ImGuiViewport* viewport);
+4387:CIMGUI_API ImVec2_c igCalcTextSize(const char* text,const char* text_end,bool hide_text_after_double_hash,float wrap_width);
+4388:CIMGUI_API ImVec4_c igColorConvertU32ToFloat4(ImU32 in);
+4405:CIMGUI_API bool igIsMouseDoubleClicked_Nil(ImGuiMouseButton button);
+5092:CIMGUI_API ImDrawList* igGetForegroundDrawList_WindowPtr(ImGuiWindow* window);
+5161:CIMGUI_API void igBeginDisabledOverrideReenable(void);
+5244:CIMGUI_API bool igIsMouseDoubleClicked_ID(ImGuiMouseButton button,ImGuiID owner_id);

linker.script

@@ -34,4 +34,14 @@ SECTIONS
   }
   end = .; _end = .; __end = .;
   kernel_end = .;
+
+  /DISCARD/ : {
+    *(.init_array*)
+    *(.fini_array*)
+    *(.ctors)
+    *(.dtors)
+    *(.eh_frame*)
+    *(.gcc_except_table*)
+    *(.note.GNU-stack)
+  }
 }

src/console.pas

@@ -838,6 +838,18 @@ const
 	MAX_WINDOWS = 255; //< Maximum number of Windows open.
     DefaultWND  = 0;   //< The Window assigned for output when no Window is specified. (Default).
 
+type
+    TWNDCaptureCallback = procedure(s: pchar);
+
+var
+    WND_CaptureActive   : boolean = false;
+    WND_CaptureHWND     : uint32 = 0;
+    WND_CaptureBuf      : array[0..511] of char;
+    WND_CaptureBufIdx   : uint32 = 0;
+    WND_CaptureCallback : TWNDCaptureCallback = nil;
+
+procedure flushCapture;
+
 implementation
 
 uses
@@ -1776,14 +1788,15 @@ var
    fb: puint32;
 
 Begin
+     Ready:= False;
      fb:= puint32(uint32(multibootinfo^.framebuffer_addr));
      Console_Properties.Width:= multibootinfo^.framebuffer_width;
      Console_Properties.Height:= multibootinfo^.framebuffer_height;
      Console_Properties.BitsPerPixel:= multibootinfo^.framebuffer_bpp;
      Console_Properties.MAX_CELL_X:= (Console_Properties.Width div 8) - 1;
      Console_Properties.MAX_CELL_Y:= (Console_Properties.Height div 16) - 1;
-     If Console_Properties.BitsPerPixel <> 16 then while true do begin
-
+     If Console_Properties.BitsPerPixel <> 16 then begin
+        exit;
      end;
      kpalloc(uint32(fb));
      keyboard.hook(@keyhook);
@@ -2258,6 +2271,7 @@ var
    x,y: Byte;
 
 begin
+     if WND_CaptureActive and (WND = WND_CaptureHWND) then exit;
      if WindowManager.Windows[WND] <> nil then begin
         for y:=0 to Console_Properties.MAX_CELL_Y do begin
             for x:=0 to Console_Properties.MAX_CELL_X do begin
@@ -2418,8 +2432,26 @@ begin
      console.writeintlnexWND(i, Console_Properties.Default_Attribute, WND);
 end;
 
+procedure flushCapture;
+begin
+    if WND_CaptureActive and (WND_CaptureCallback <> nil) and (WND_CaptureBufIdx > 0) then begin
+        WND_CaptureBuf[WND_CaptureBufIdx] := #0;
+        WND_CaptureCallback(@WND_CaptureBuf[0]);
+        WND_CaptureBufIdx := 0;
+        WND_CaptureBuf[0] := #0;
+    end;
+end;
+
 procedure writecharexWND(character: char; attributes: uint32; WND : uint32); 
 begin
+    if WND_CaptureActive and (WND = WND_CaptureHWND) and (WND_CaptureCallback <> nil) then begin
+        if WND_CaptureBufIdx < 511 then begin
+            WND_CaptureBuf[WND_CaptureBufIdx] := character;
+            inc(WND_CaptureBufIdx);
+            WND_CaptureBuf[WND_CaptureBufIdx] := #0;
+        end;
+        exit;
+    end;
     if WindowManager.Windows[WND] <> nil then begin
         WindowManager.Windows[WND]^.Buffer[WindowManager.Windows[WND]^.Cursor.Y][WindowManager.Windows[WND]^.Cursor.X].Character:= character;
         WindowManager.Windows[WND]^.Buffer[WindowManager.Windows[WND]^.Cursor.Y][WindowManager.Windows[WND]^.Cursor.X].Attributes:= attributes;
@@ -2602,6 +2634,13 @@ end;
 
 procedure backspaceWND(WND : uint32);
 begin
+     if WND_CaptureActive and (WND = WND_CaptureHWND) then begin
+        if WND_CaptureBufIdx > 0 then begin
+            dec(WND_CaptureBufIdx);
+            WND_CaptureBuf[WND_CaptureBufIdx] := #0;
+        end;
+        exit;
+     end;
      if WindowManager.Windows[WND] <> nil then begin
         Dec(WindowManager.Windows[WND]^.Cursor.X);
         writecharWND(' ', WND);
@@ -2658,6 +2697,13 @@ end;
 
 procedure _safeincrement_y_WND(WND : uint32);
 begin
+     if WND_CaptureActive and (WND = WND_CaptureHWND) and (WND_CaptureCallback <> nil) then begin
+        WND_CaptureBuf[WND_CaptureBufIdx] := #0;
+        WND_CaptureCallback(@WND_CaptureBuf[0]);
+        WND_CaptureBufIdx := 0;
+        WND_CaptureBuf[0] := #0;
+        exit;
+     end;
      if WindowManager.Windows[WND] <> nil then begin
         WindowManager.Windows[WND]^.Cursor.Y:= WindowManager.Windows[WND]^.Cursor.Y+1;
         if WindowManager.Windows[WND]^.Cursor.Y > WindowManager.Windows[WND]^.WND_H-1 then begin

src/cpu.pas

@@ -291,6 +291,28 @@ begin
     end;
 end;
 
+procedure enableAVX();
+begin
+    if CPUID.Capabilities1^.AVX then begin
+        asm
+            PUSH EAX
+            PUSH ECX
+            PUSH EDX
+            XOR ECX, ECX
+            db $0F
+            db $01
+            db $D0
+            OR EAX, 7
+            db $0F
+            db $01
+            db $D1
+            POP EDX
+            POP ECX
+            POP EAX
+        end;
+    end;
+end;
+
 procedure init();
 begin
     terminal.registerCommand('CPU', @Terminal_Command_CPU, 'CPU Info.');
@@ -300,6 +322,7 @@ begin
     getCPUCapabilities;
     getCPUClockSpeed;
     enableSSE;
+    enableAVX;
 end;
 
 end.

src/driver/hid/mouse.pas

@@ -49,8 +49,12 @@ type
         y : sint32;
     end;
 
+    { Mouse hook callback: receives absolute position and button states }
+    TMouseHook = procedure(x, y: sint32; lmb, rmb, mmb: boolean);
+
 procedure init();
 procedure DrawCursor;
+procedure setHook(h: TMouseHook);
 
 implementation
 
@@ -67,6 +71,7 @@ var
     LMouseDownPos : TMousePos;
     LMouseDown : Boolean;
     RMouseDown : Boolean;
+    MouseHookCB : TMouseHook = nil;
 
 procedure DrawCursor;
 var
@@ -174,43 +179,38 @@ begin
                 if Current.y > (Console.getConsoleProperties^.Height-8) then Current.y:= (Console.getConsoleProperties^.Height-8);
             end;
             Cycle:= 0;
-            if Packet.LMB_Down then begin
-                if not LMouseDown then begin
-                    LMouseDown:= true;
-                    LMouseDownPos.x:= Current.x;
-                    LMouseDownPos.y:= Current.y;
-                    //MouseDownEvent
-                    console._mouseDown();
-                end;
+            { Track button transitions }
+            if Packet.LMB_Down and (not LMouseDown) then begin
+                LMouseDown:= true;
+                LMouseDownPos.x:= Current.x;
+                LMouseDownPos.y:= Current.y;
             end;
-            if not Packet.LMB_Down then begin
-                if LMouseDown then begin
-                    If (Current.x = LMouseDownPos.x) and (Current.y = LMouseDownPos.y) then begin
-                        Console._MouseClick(true);
-                    end;
-                    //MouseUpEvent
-                    Console._MouseUp();
-                    LMouseDown:= false;
-                end;
+            if (not Packet.LMB_Down) and LMouseDown then
+                LMouseDown:= false;
+            if Packet.RMB_Down and (not RMouseDown) then begin
+                RMouseDown:= true;
+                RMouseDownPos.x:= Current.x;
+                RMouseDownPos.y:= Current.y;
             end;
-            if Packet.RMB_Down then begin
-                if not RMouseDown then begin
-                    RMouseDown:= true;
-                    RMouseDownPos.x:= Current.x;
-                    RMouseDownPos.y:= Current.y;
-                end;
-            end;
-            
-            if not Packet.RMB_Down then begin
-                if RMouseDown then begin
-                    if (Current.x = RMouseDownPos.x) and (Current.y = RMouseDownPos.y) then begin
-                        Console._MouseClick(false);
-                    end;
-                end;
+            if (not Packet.RMB_Down) and RMouseDown then
                 RMouseDown:= false;
+
+            { Dispatch to hook or console }
+            if MouseHookCB <> nil then
+                MouseHookCB(Current.x, Current.y, Packet.LMB_Down, Packet.RMB_Down, Packet.MMB_Down)
+            else begin
+                if Packet.LMB_Down and (not LMouseDown) then console._mouseDown();
+                if (not Packet.LMB_Down) and LMouseDown then begin
+                    if (Current.x = LMouseDownPos.x) and (Current.y = LMouseDownPos.y) then
+                        Console._MouseClick(true);
+                    Console._MouseUp();
+                end;
+                if (not Packet.RMB_Down) and RMouseDown then begin
+                    if (Current.x = RMouseDownPos.x) and (Current.y = RMouseDownPos.y) then
+                        Console._MouseClick(false);
+                end;
+                console.setMousePosition(Current.x, Current.y);
             end;
-            
-            console.setMousePosition(Current.x, Current.y);
         end;
     end;
 end;
@@ -242,6 +242,11 @@ begin
     pop_trace;
 end;
 
+procedure setHook(h: TMouseHook);
+begin
+    MouseHookCB := h;
+end;
+
 procedure init();
 var
     devid : TDeviceIdentifier;

src/driver/storage/vfs.pas

@@ -92,6 +92,7 @@ var
     Root              : PVFSObject;
     CurrentDirectory  : pchar = nil;
     PushPopDirectory  : PLinkedListBase;
+    MountDepth        : uint32 = 0;
 
 procedure init();
 Function OpenFile(Filename : pchar; OpenMode : TOpenMode; WriteMode : TWriteMode; Lock : Boolean; Error : PError) : TFileHandle;
@@ -104,6 +105,7 @@ function GetDirectories(Handle : uint32; Path : pchar) : PHashMap;
 function PathValid(Path : pchar) : TIsPathValid;
 function changeDirectory(Path : pchar) : TIsPathValid;
 function getWorkingDirectory : pchar;
+function GetDirectoryListing(Path : pchar) : PHashMap;
 
 //VFS Functions
 function newVirtualDirectory(Path : pchar) : TError;
@@ -288,6 +290,7 @@ begin
             NewObj:= PVFSObject(hashmap.get(ht, item));                                            
             if NewObj = nil then begin                                                              
                 GetObjectFromPath:= nil;
+                STRLL_Free(SplitPath);
                 tracer.push_trace('vfs.GetObjectFromPath.shortexit_1');
                 exit;
             end;                                                                                    
@@ -304,6 +307,7 @@ begin
         end;
     end;                                                                                           
     GetObjectFromPath:= Obj;
+    STRLL_Free(SplitPath);
     tracer.push_trace('vfs.GetObjectFromPath.exit');
 end;
 
@@ -348,7 +352,17 @@ begin
                 GetDirectoryListing:= nil;
             end; 
             otMOUNT:begin
-                GetDirectoryListing:= GetDirectoryListing(PVFSMount(Obj^.Reference)^.Path);
+                { Safety: cap mount-follow depth to prevent infinite recursion
+                  from circular mounts.  Use a simple static counter. }
+                if MountDepth < 16 then begin
+                    Inc(MountDepth);
+                    GetDirectoryListing:= GetDirectoryListing(PVFSMount(Obj^.Reference)^.Path);
+                    Dec(MountDepth);
+                end else
+                    GetDirectoryListing:= nil;
+            end;
+            else begin
+                GetDirectoryListing:= nil;
             end;
         end;
     end else begin
@@ -420,7 +434,7 @@ begin
 
     NewObj^.Reference:= void(NewDev);
 
-    hashmap.add(ht, stringCopy(DeviceName), void(NewDev));
+    hashmap.add(ht, stringCopy(DeviceName), void(NewObj));
 end;
 
 { Filesystem Functions }

src/driver/video/doublebuffer.pas

@@ -0,0 +1,116 @@
+//  Copyright 2021 Kieron Morris
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+{ 
+	Driver->Video->Doublebuffer - Implements a very basic double buffer, tested with VESA drivers.
+	
+	@author(Kieron Morris <[email protected]>)
+}
+unit doublebuffer;
+
+interface
+
+uses
+    lmemorymanager, tracer, videotypes, serial, util;
+
+//Init the driver, and register with the video interface in a state ready for execution.
+procedure init(Register : FRegisterDriver);
+
+implementation
+
+function allocateBackBuffer(Width : uint32; Height : uint32; BitsPerPixel : uint8) : uint64;
+begin
+    tracer.push_trace('doublebuffer.allocateBackBuffer.enter');
+    //This doesn't currently work... Needs a rework of lmemorymanager
+    allocateBackBuffer:= uint64(klalloc((Width * Height) * BitsPerPixel));
+    tracer.push_trace('doublebuffer.allocateBackBuffer.exit');
+end;
+
+procedure initBackBuffer(VInterface : PVideoInterface; Width : uint32; Height : uint32; BitsPerPixel : uint8);
+begin
+    tracer.push_trace('doublebuffer.initBackBuffer.enter');
+    if not(VInterface^.BackBuffer.Initialized) then begin
+        VInterface^.BackBuffer.Location:= allocateBackBuffer(Width, Height, BitsPerPixel);
+        if (VInterface^.BackBuffer.Location <> 0) then begin
+            VInterface^.BackBuffer.Width:= Width;
+            VInterface^.BackBuffer.Height:= Height;
+            VInterface^.BackBuffer.BitsPerPixel:= BitsPerPixel;
+            VInterface^.BackBuffer.Initialized:= True;
+        end;
+    end;
+    tracer.push_trace('doublebuffer.initBackBuffer.exit');
+end;
+
+procedure Flush(FrontBuffer : PVideoBuffer; BackBuffer : PVideoBuffer);
+var
+    Back,Front : uint32;
+    Count64 : uint32;
+
+begin
+    //tracer.push_trace('doublebuffer.Flush.enter');
+    if not(BackBuffer^.Initialized) then exit;
+    if ((FrontBuffer^.Width > BackBuffer^.Width) or (FrontBuffer^.Height > BackBuffer^.Height)) then exit;
+    Back:= BackBuffer^.Location;
+    Front:= FrontBuffer^.Location;
+    { Number of 64-byte blocks: total_bytes / 64 = (W * H * BPP/8) / 64 }
+    Count64:= ( BackBuffer^.Width * BackBuffer^.Height * BackBuffer^.BitsPerPixel) div 512;
+    if Count64 = 0 then exit;
+    { Bulk SSE copy: 4 x MOVAPS (64 bytes) per iteration.
+      4x fewer loop iterations than the old per-16-byte function-call loop. }
+    asm
+        PUSH ESI
+        PUSH EDI
+        MOV ESI, Back
+        MOV EDI, Front
+        MOV ECX, Count64
+    @sseloop:
+        MOVAPS XMM0, [ESI]
+        MOVAPS XMM1, [ESI + 16]
+        MOVAPS XMM2, [ESI + 32]
+        MOVAPS XMM3, [ESI + 48]
+        MOVAPS [EDI], XMM0
+        MOVAPS [EDI + 16], XMM1
+        MOVAPS [EDI + 32], XMM2
+        MOVAPS [EDI + 48], XMM3
+        ADD ESI, 64
+        ADD EDI, 64
+        DEC ECX
+        JNZ @sseloop
+        POP EDI
+        POP ESI
+    end;
+    //tracer.push_trace('doublebuffer.Flush.exit');
+end;
+
+function enable(VideoInterface : PVideoInterface) : boolean;
+begin
+    tracer.push_trace('doublebuffer.enable.enter');
+    enable:= false;
+    initBackBuffer(VideoInterface, VideoInterface^.FrontBuffer.Width, VideoInterface^.FrontBuffer.Height, VideoInterface^.FrontBuffer.BitsPerPixel);
+    if VideoInterface^.BackBuffer.Initialized then begin
+        VideoInterface^.DefaultBuffer:= @VideoInterface^.BackBuffer;
+        VideoInterface^.DrawRoutines.Flush:= @Flush;
+        enable:= true;
+    end;
+    tracer.push_trace('doublebuffer.enable.exit');
+end;
+
+procedure init(Register : FRegisterDriver);
+begin
+    tracer.push_trace('doublebuffer.init.enter');
+    Register('BASIC_DOUBLE_BUFFER', @enable);
+    tracer.push_trace('doublebuffer.init.exit');
+end;
+
+end.

src/driver/video/vesa.pas

@@ -0,0 +1,87 @@
+//  Copyright 2021 Kieron Morris
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+{ 
+	Driver->Video->VESA - VESA Display Driver.
+	
+	@author(Kieron Morris <[email protected]>)
+}
+unit vesa;
+
+interface
+
+uses
+    videotypes, tracer, multiboot, lmemorymanager;
+
+//Init the driver, and register with the video interface in a state ready for execution.
+procedure init(Register : FRegisterDriver);
+
+implementation
+
+uses
+    VESA8, VESA16, VESA24, VESA32;
+
+procedure allocateVESAFrameBuffer(Address : uint32; Width : uint32; Height : uint32);
+var
+    LowerAddress, UpperAddress : uint32;
+    Block : uint32;
+
+begin
+    tracer.push_trace('VESA.allocateFrameBuffer.enter');
+    LowerAddress:= ((Address) SHR 22)-1;
+    UpperAddress:= ((Address + (Width * Height)) SHR 22)+1;
+    For Block:=LowerAddress to UpperAddress do begin
+        kpalloc(Block SHL 22);
+    end;
+    tracer.push_trace('VESA.allocateFrameBuffer.exit');
+end;
+
+procedure initVESAFrameBuffer(VideoBuffer : PVideoBuffer; Location : uint64; Width : uint32; Height : uint32; BitsPerPixel : uint8);
+begin
+    tracer.push_trace('VESA.initVESAFrameBuffer.enter');
+    if not(VideoBuffer^.Initialized) then begin
+        VideoBuffer^.Location:= Location;
+        VideoBuffer^.BitsPerPixel:= BitsPerPixel;
+        VideoBuffer^.Width:= Width;
+        VideoBuffer^.Height:= Height;
+        allocateVESAFrameBuffer(VideoBuffer^.Location, VideoBuffer^.Width, VideoBuffer^.Height);
+        if VideoBuffer^.Location <> 0 then
+            VideoBuffer^.Initialized:= True;
+    end;
+    tracer.push_trace('VESA.initVESAFrameBuffer.exit');
+end;
+
+function enable(VideoInterface : PVideoInterface) : boolean;
+begin
+    tracer.push_trace('VESA.enable.enter');
+    initVESAFrameBuffer(@VideoInterface^.FrontBuffer, multiboot.multibootinfo^.framebuffer_addr, multiboot.multibootinfo^.framebuffer_width, multiboot.multibootinfo^.framebuffer_height, multiboot.multibootinfo^.framebuffer_bpp);
+    case (VideoInterface^.FrontBuffer.BitsPerPixel) of
+        08:VESA8.init(@VideoInterface^.DrawRoutines);
+        16:VESA16.init(@VideoInterface^.DrawRoutines);
+        24:VESA24.init(@VideoInterface^.DrawRoutines);
+        32:VESA32.init(@VideoInterface^.DrawRoutines);
+    end;
+    enable:= VideoInterface^.FrontBuffer.Initialized;  
+    tracer.push_trace('VESA.enable.exit');
+end;
+
+procedure init(Register : FRegisterDriver);
+begin
+    tracer.push_trace('VESA.init.enter');
+    if Register <> nil then
+        Register('VESA', @enable);   
+    tracer.push_trace('VESA.init.exit');
+end;
+
+end.

src/driver/video/vesa16.pas

@@ -0,0 +1,43 @@
+//  Copyright 2021 Kieron Morris
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+{ 
+	Driver->Video->VESA16 - Implementation of VESA 16bpp draw routines for the VESA Driver.
+	
+	@author(Kieron Morris <[email protected]>)
+}
+unit vesa16;
+
+interface
+
+uses
+    videotypes, vesa, tracer, color;
+
+//Init the draw routines by providing what we support through the DrawRoutines struct.
+procedure init(DrawRoutines : PDrawRoutines);
+
+implementation
+
+procedure DrawPixel(Buffer : PVideoBuffer; X : uint32; Y : uint32; Pixel : TRGB32);
+begin
+
+end;
+
+procedure init(DrawRoutines : PDrawRoutines);
+begin
+    tracer.push_trace('vesa16.init.enter');   
+    tracer.push_trace('vesa16.init.exit');
+end;
+
+end.

src/driver/video/vesa24.pas

@@ -0,0 +1,43 @@
+//  Copyright 2021 Kieron Morris
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+{ 
+	Driver->Video->VESA24 - Implementation of VESA 24bpp draw routines for the VESA Driver.
+	
+	@author(Kieron Morris <[email protected]>)
+}
+unit vesa24;
+
+interface
+
+uses
+    videotypes, vesa, tracer, color;
+
+//Init the draw routines by providing what we support through the DrawRoutines struct.
+procedure init(DrawRoutines : PDrawRoutines);
+
+implementation
+
+procedure DrawPixel(Buffer : PVideoBuffer; X : uint32; Y : uint32; Pixel : TRGB32);
+begin
+
+end;
+
+procedure init(DrawRoutines : PDrawRoutines);
+begin
+	tracer.push_trace('vesa24.init.enter');
+	tracer.push_trace('vesa24.init.exit');
+end;
+
+end.