mirror of
https://github.com/gbowne1/ClassicOS.git
synced 2024-11-21 13:56:53 -08:00
fixed up some bad comments in boot.asm
This commit is contained in:
parent
6c4ee8ed02
commit
a6f5bdb64c
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.vscode/launch.json
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.vscode/launch.json
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@ -4,6 +4,7 @@
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// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
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"version": "0.2.0",
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"configurations": [
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{
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"name": "gcc-8 - Build and debug active file Level 1",
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"type": "cppdbg",
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@ -27,6 +28,16 @@
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"logging": {
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"engineLogging": true
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}
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},
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{
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"name": "Debug with QEMU",
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"type": "cppdbg",
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"request": "launch",
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"program": "${workspaceFolder}/boot.bin",
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"miDebuggerPath": "/usr/bin/qemu-system-i386",
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"miDebuggerArgs": "-kernel",
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"cwd": "${workspaceFolder}",
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"preLaunchTask": "build"
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}
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]
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}
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165
.vscode/settings.json
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.vscode/settings.json
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@ -1,113 +1,66 @@
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{
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"files.associations": {
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"*.c": "c",
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"*.h": "c",
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"*.cpp": "cpp",
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"*.hpp": "hpp",
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"*.asm": "asm",
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"*.bin": "bin"
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},
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"files.fileAssociations": {
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".c": "c",
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".h": "c",
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".cpp": "cpp",
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".hpp": "cpp",
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".asm": "asm",
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".bin": "bin"
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},
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"emmet.includeLanguages": {
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"c": "c",
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"cpp": "cpp",
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"assembly": "asm"
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},
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"C_Cpp_Runner.cCompilerPath": "/usr/bin",
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"C_Cpp_Runner.cppCompilerPath": "/usr/bin",
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"C_Cpp_Runner.debuggerPath": "/usr/bin",
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"C_Cpp_Runner.cStandard": "c17",
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"C_Cpp_Runner.cppStandard": "c++20",
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"C_Cpp_Runner.msvcBatchPath": "C:/Program Files/Microsoft Visual Studio/2022/Community/VC/Auxiliary/Build/vcvarsall.bat",
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"C_Cpp_Runner.useMsvc": false,
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"C_Cpp_Runner.warnings": [
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"-Wall",
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"-Wextra",
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"-Wextra",
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"-Wpedantic"
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],
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"C_Cpp_Runner.enableWarnings": true,
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"C_Cpp_Runner.warningsAsError": false,
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"C_Cpp_Runner.compilerArgs": [],
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"C_Cpp_Runner.linkerArgs": [
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"-dynamic-linker {/lib64/ld-linux-x86-64.so.2}"
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],
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"C_Cpp_Runner.includePaths": [],
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"C_Cpp_Runner.includeSearch": [
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"*",
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"**/*"
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],
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"C_Cpp_Runner.excludeSearch": [
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"**/build",
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"**/build/**",
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"**/.*",
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"**/.*/**",
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"**/.vscode",
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"**/.vscode/**"
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],
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"C_Cpp_Runner.useAddressSanitizer": false,
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"C_Cpp_Runner.showCompilationTime": false,
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"c-cpp-flylint.enable": true,
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"c-cpp-flylint.debug": true,
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"c-cpp-flylint.flexelint.enable": false,
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"c-cpp-flylint.cppcheck.enable": true,
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"c-cpp-flylint.clang.enable": false,
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"C_Cpp_Config.cCompilerPath": "gcc",
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"C_Cpp_Config.cppCompilerPath": "g++",
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"C_Cpp_Config.debuggerPath": "gdb",
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"C_Cpp_Config.makePath": "make",
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// General C/C++ settings
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"C_Cpp.autoAddFileAssociations": true,
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"C_Cpp.autocompleteAddParentheses": true,
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"C_Cpp.clang_format_sortIncludes": true,
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"C_Cpp.vcFormat.indent.preserveComments": true,
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"C_Cpp.vcFormat.indent.namespaceContents": false,
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"C_Cpp.vcFormat.indent.caseContentsWhenBlock": true,
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"C_Cpp.vcFormat.space.pointerReferenceAlignment": "right",
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"C_Cpp.default.browse.limitSymbolsToIncludedHeaders": false,
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"C_Cpp.default.cppStandard": "c++20",
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"C_Cpp.default.cStandard": "c17",
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"C_Cpp.formatting": "clangFormat",
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"[c]": {
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"editor.formatOnSave": true,
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"editor.defaultFormatter": "ms-vscode.cpptools"
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},
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"[cpp]": {
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"editor.formatOnSave": true,
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"editor.defaultFormatter": "ms-vscode.cpptools"
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},
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"C_Cpp.codeAnalysis.clangTidy.enabled": true,
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"C_Cpp.configurationWarnings": "disabled",
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"cmake.configureOnOpen": false,
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"C_Cpp.configurationWarnings": "enabled",
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"C_Cpp.default.browse.limitSymbolsToIncludedHeaders": false,
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"C_Cpp.default.cStandard": "c11",
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"C_Cpp.default.compilerPath": "",
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"C_Cpp.default.cppStandard": "c++11",
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"C_Cpp.default.enableConfigurationSquiggles": true,
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"C_Cpp.errorSquiggles": "enabledIfIncludesResolve",
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"C_Cpp.formatting": "default",
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"C_Cpp.loggingLevel": "Debug",
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"C_Cpp.vcFormat.indent.caseContentsWhenBlock": true,
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"C_Cpp.vcFormat.indent.namespaceContents": false,
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"C_Cpp.vcFormat.indent.preserveComments": true,
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"C_Cpp.vcFormat.space.pointerReferenceAlignment": "right",
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// CMake integration settings
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"cmake.autoSelectActiveFolder": false,
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"cmake.configureOnEdit": false,
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"c-cpp-flylint.flexelint.configFile": "",
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"c-cpp-flylint.flexelint.executable": "",
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"c-cpp-flylint.language": "c",
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"C_Cpp.autocompleteAddParentheses": true,
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"C_Cpp.errorSquiggles": "enabled",
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"C_Cpp_Runner.makePath": "",
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"cmake.sourceDirectory": "${workspaceFolder}",
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"C_Cpp.default.compilerPath": "/usr/bin",
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"C_Cpp.loggingLevel": "Error",
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"C_Cpp.default.enableConfigurationSquiggles": true,
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"C_Cpp.default.includePath": [
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"${workspaceFolder}/**", // Include all files in the workspace folder
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"/usr/include", // Standard system include path
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"/usr/local/include", // Additional system include path
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"/path/to/custom/includes" // Custom include path
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],
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"workbench.editorAssociations": {
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"*.bin": "default",
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"*.h": "default",
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"*.c": "default",
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"*.json": "default",
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"*.asm": "default"
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"cmake.configureOnOpen": false,
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"cmake.cmakePath": "/usr/bin/cmake",
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"cmake.sourceDirectory": "${workspaceFolder}/",
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// Language-specific settings
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"[c]": {
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"editor.defaultFormatter": "ms-vscode.cpptools",
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"editor.formatOnSave": true
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},
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"C_Cpp.default.intelliSenseMode": "linux-gcc-x86",
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"cmake.cmakePath": "/usr/bin/cmake"
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"[cpp]": {
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"editor.defaultFormatter": "ms-vscode.cpptools",
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"editor.formatOnSave": true
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},
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// File associations
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"files.associations": {
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"*.c": "c",
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"*.cpp": "cpp",
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"*.h": "c",
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"*.hpp": "c"
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},
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"workbench.editorAssociations": {
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"*.c": "default",
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"*.cpp": "default",
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"*.h": "default",
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"*.hpp": "default"
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},
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// IntelliSense configuration
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"C_Cpp.default.includePath": [
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"/usr/include",
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"${workspaceFolder}/**",
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"${workspaceFolder}/src/include",
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"${workspaceFolder}/include"
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],
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"C_Cpp.default.defines": [],
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"C_Cpp.default.compileCommands": "build/compile_commands.json",
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"C_Cpp.default.browse.path": [
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"/usr/include",
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"${workspaceFolder}/**",
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"${workspaceFolder}/src/include",
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"${workspaceFolder}/include"
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],
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"C_Cpp.default.browse.databaseFilename": "${workspaceFolder}/.vscode/browse.vc.db",
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"C_Cpp.default.configurationProvider": "ms-vscode.cpptools",
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"C_Cpp.default.intelliSenseMode": "linux-gcc-x64",
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}
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@ -16,10 +16,10 @@ identify_drive:
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cmp cl, 0x80 ; Check for hard disk interrupt vector (example)
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je is_harddrive
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; Handle invalid drive type (error handling)
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...
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; ...
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is_floppy:
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Perform floppy disk access (assuming AH=0x02 for read sectors)
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; Perform floppy disk access (assuming AH=0x02 for read sectors)
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mov ah, 0x02 ; Read sectors
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mov al, 1 ; Number of sectors to read (1)
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@ -68,8 +68,8 @@ memory_error:
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; ... (error handling or continue with limited memory)
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; Second stage loading (simplified example)
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Here's an improved version of the load_second_stage section with the placeholder jump replaced by actual loading logic:
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Code snippet
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; Here's an improved version of the load_second_stage section with the placeholder jump replaced by actual loading logic:
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; Code snippet
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load_second_stage:
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; Calculate address of second stage bootloader (assuming offset from boot sector)
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@ -8,89 +8,82 @@ start:
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MOV SP, 0xFFFF ; Stack grows downwards from the top of the segment
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; Copy boot sector data to a safe location
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mCopyBootSector
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call mCopyBootSector
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; Load the kernel
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CALL load_kernel
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switch_to_protected_mode:
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CLI ; Disable interrupts
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lgdt [gdt_descriptor] ; Load the global descriptor table
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MOV EAX, CR0
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OR EAX, 0x1 ; Set the PE (Protection Enable) bit
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MOV CR0, EAX
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; Far jump to flush CPU queue after changing to protected mode
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JMP CODE_SEG:init_pm ; CODE_SEG is the segment selector for code segment in GDT
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init_pm:
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; Update segment registers here
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; Set code segment register (CS) to point to code segment descriptor (selector 1)
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mov ax, 0x0001
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mov ds, ax ; Set data segment register (DS) to point to data segment descriptor (selector 2)
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mov es, ax ; Set other segment registers (ES, SS, etc.) as needed
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RET
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switch_to_protected_mode:
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CLI ; Disable interrupts
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lgdt [gdt_descriptor] ; Load the global descriptor table
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MOV EAX, CR0
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OR EAX, 0x1 ; Set the PE (Protection Enable) bit
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MOV CR0, EAX
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; Far jump to flush CPU queue after changing to protected mode
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JMP CODE_SEG:init_pm ; CODE_SEG is the segment selector for code segment in GDT
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init_pm:
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; Update segment registers here
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; Set code segment register (CS) to point to code segment descriptor (selector 1)
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mov ax, 0x0001
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mov ds, ax ; Set data segment register (DS) to point to data segment descriptor (selector 2)
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mov es, ax ; Set other segment registers (ES, SS, etc.) as needed
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RET
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enable_a20:
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cli ; Disable interrupts to prevent interference
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call a20wait ; Wait for the keyboard controller to be ready
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mov al, 0xAD ; Command to disable keyboard
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out 0x64, al ; Send command to keyboard controller command port
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call a20wait ; Wait for the keyboard controller to be ready
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mov al, 0xD0 ; Command to read output port
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out 0x64, al ; Send command to keyboard controller command port
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call a20wait ; Wait for the keyboard controller to be ready
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in al, 0x60 ; Read current state of output port
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or al, 0x02 ; Set A20 bit
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out 0x64, al ; Send command to keyboard controller command port
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call a20wait ; Wait for the keyboard controller to be ready
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mov al, 0xD1 ; Command to write output port
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out 0x64, al ; Send command to keyboard controller command port
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call a20wait ; Wait for the keyboard controller to be ready
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mov al, 0xAE ; Command to re-enable keyboard
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out 0x64, al ; Send command to keyboard controller command port
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sti ; Re-enable interrupts
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ret
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enable_a20:
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; Enable A20 gate
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cli ; Disable interrupts to prevent interference
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call a20wait ; Wait for the keyboard controller to be ready
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mov al, 0xAD ; Command to disable keyboard
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out 0x64, al ; Send command to keyboard controller command port
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call a20wait ; Wait for the keyboard controller to be ready
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mov al, 0xD0 ; Command to read output port
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out 0x64, al ; Send command to keyboard controller command port
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call a20wait ; Wait for the keyboard controller to be ready
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in al, 0x60 ; Read current state of output port
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or al, 0x02 ; Set A20 bit
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call a20wait ; Wait for the keyboard controller to be ready
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mov al, 0xD1 ; Command to write output port
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out 0x64, al ; Send command to keyboard controller command port
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call a20wait ; Wait for the keyboard controller to be ready
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mov al, 0x02 ; New output port data with A20 enabled
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out 0x60, al ; Write new output port data
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call a20wait ; Wait for the keyboard controller to be ready
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sti ; Re-enable interrupts
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ret
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; Wait for keyboard controller to be ready
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a20wait:
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in al, 0x64 ; Read keyboard controller status port
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test al, 0x02 ; Check if input buffer is full
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jnz a20wait ; Wait until it's not full
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ret
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; Wait for keyboard controller to be ready
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a20wait:
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in al, 0x64 ; Read keyboard controller status port
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test al, 0x02 ; Check if input buffer is full
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jnz a20wait ; Wait until it's not full
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ret
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; Enter kernel space and jump to the kernel entry point
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JMP 0x1000:0x0000
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; Enter kernel space and jump to the kernel entry point
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JMP 0x1000:0x0000
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; Code to set up flat memory model for protected mode
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; This involves setting up the segment registers with selectors
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; that point to descriptors in the GDT that define a flat memory model
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; Code to set up flat memory model for protected mode
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; This involves setting up the segment registers with selectors
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; that point to descriptors in the GDT that define a flat memory model
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limit = 0x00CFFFFFh ; Define limit as a separate variable within gdt_struct
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; Define GDT structure
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gdt_struct:
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; Null descriptor (ignored)
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dq 0x0000000000000000h
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dq 0x0000000000000000h
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; Placeholder instruction to satisfy NASM
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dummy_instruction DB 0x90 ; NOP instruction as a placeholder
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; Code segment descriptor (flat memory model)
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; Base address 0, limit 0xffffffff (full 4GB)
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; Present, Readable, Accessed, Code segment, 4KB granularity
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; Flags: 0x9A (Bits explained below)
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dq 0x0000000000000000h
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dq 0x00CFFFFFFFh
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db 0x9A
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db 0xCF
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gdt_struct:
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; Data segment descriptor (flat memory model)
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; Similar structure to code segment descriptor with Data segment flag set
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dq 0x0000000000000000h
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dq 0x00CFFFFFFFh
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db 0x92
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db 0xCF
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base_addr equ 0x0000000
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; Jump to the kernel entry point
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JMP 0x1000:0x0000 ; Assuming the kernel is loaded at 0x1000:0x0000
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; Null descriptor (ignored)
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dd base_addr, 0 ; Both values are zero for a null descriptor
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; Code segment descriptor (flat memory model)
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dd base_addr, limit
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db 0x9A
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db 0xCF
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; Data segment descriptor (flat memory model)
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dd base_addr, limit
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db 0x92
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db 0xCF
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; Macro to copy boot sector data to a safe location
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mCopyBootSector:
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@ -28,7 +28,4 @@ SECTIONS {
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bootloader_padding : {
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*(.bootloader_padding)
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}
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/* Set the bootloader size to 512 bytes */
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= 512;
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}
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