Added some more stdlib.

SConstruct

@@ -22,11 +22,16 @@ crti_o = env.Object('src/crt/crti.s')
 crtn_o = env.Object('src/crt/crtn.s')
 
 os_sources = Split('''
+    src/app/main.cpp
+
     src/kernel/boot.s
     src/kernel/startup.cpp
 
     src/os/tty.cpp
 
+    src/stdlib/assert.cpp
+    src/stdlib/stdio.cpp
+    src/stdlib/stdlib.cpp
     src/stdlib/string.cpp
 ''')
 env['LINKCOM'] = env['LINKCOM'].replace('$_LIBFLAGS', f'{crti_o[0]} {crtbegin_o} $_LIBFLAGS {crtend_o} {crtn_o[0]}')

include/assert.h

@@ -0,0 +1,27 @@
+
+#pragma once
+
+#if !defined(BAD_APPLE_OS_ASSERT_H_INCLUDED)
+#define BAD_APPLE_OS_ASSERT_H_INCLUDED
+
+#include "./detail/common.h"
+
+BA_EXTERN_C_BEGIN
+
+#if defined(NDEBUG)
+#define assert(condition) ((void) 0)
+#else
+#define assert(condition) \
+if (!(condition)) \
+{ \
+    __ba__assert_fail(__FILE__, __LINE__, #condition); \
+}
+#endif
+
+#if !defined(NDEBUG)
+BA_CXX_NORETURN void __ba__assert_fail(const char* filename, int line, const char* condition) BA_CXX_NOEXCEPT;
+#endif
+
+BA_EXTERN_C_END
+
+#endif // !defined(BAD_APPLE_OS_ASSERT_H_INCLUDED)

include/cassert

@@ -0,0 +1,9 @@
+
+#pragma once
+
+#if !defined(BAD_APPLE_OS_CASSERT_INCLUDED)
+#define BAD_APPLE_OS_CASSERT_INCLUDED
+
+#include <assert.h>
+
+#endif // !defined(BAD_APPLE_OS_CASSERT_INCLUDED)

include/cstdio

@@ -0,0 +1,16 @@
+
+#pragma once
+
+#if !defined(BAD_APPLE_OS_CSTDIO_INCLUDED)
+#define BAD_APPLE_OS_CSTDIO_INCLUDED
+
+#include <stdio.h>
+
+namespace std
+{
+using ::putchar;
+using ::puts;
+using ::printf;
+}
+
+#endif // !defined(BAD_APPLE_OS_CSTDIO_INCLUDED)

include/cstdlib

@@ -0,0 +1,14 @@
+
+#pragma once
+
+#if !defined(BAD_APPLE_OS_CSTDLIB_INCLUDED)
+#define BAD_APPLE_OS_CSTDLIB_INCLUDED
+
+#include <stdlib.h>
+
+namespace std
+{
+using ::abort;
+}
+
+#endif // !defined(BAD_APPLE_OS_CSTDLIB_INCLUDED)

include/cstring

@@ -1,14 +1,19 @@
 
 #pragma once
 
-#if !defined(BAD_APPLE_OS_CSTRING_HPP_INCLUDED)
-#define BAD_APPLE_OS_CSTRING_HPP_INCLUDED
+#if !defined(BAD_APPLE_OS_CSTRING_INCLUDED)
+#define BAD_APPLE_OS_CSTRING_INCLUDED
 
 #include <string.h>
 
 namespace std
 {
 using ::strlen;
+
+using ::memcmp;
+using ::memcpy;
+using ::memmove;
+using ::memset;
 }
 
-#endif // !defined(BAD_APPLE_OS_CSTRING_HPP_INCLUDED)
+#endif // !defined(BAD_APPLE_OS_CSTRING_INCLUDED)

include/detail/common.h

@@ -6,10 +6,16 @@
 
 #if defined(__cplusplus)
 #define BA_CXX_NODISCARD [[nodiscard]]
+#define BA_CXX_NORETURN [[noreturn]]
 #define BA_CXX_NOEXCEPT noexcept
+#define BA_EXTERN_C_BEGIN extern "C" {
+#define BA_EXTERN_C_END }
 #else
 #define BA_CXX_NODISCARD
+#define BA_CXX_NORETURN
 #define BA_CXX_NOEXCEPT
+#define BA_EXTERN_C_BEGIN
+#define BA_EXTERN_C_END
 #endif
 
 #endif // !defined(BAD_APPLE_OS_DETAIL_ATTRIBUTES_H_INCLUDED)

include/stdio.h

@@ -0,0 +1,17 @@
+
+#pragma once
+
+#if !defined(BAD_APPLE_OS_STDIO_H_INCLUDED)
+#define BAD_APPLE_OS_STDIO_H_INCLUDED
+
+#include "./detail/common.h"
+
+BA_EXTERN_C_BEGIN
+
+int putchar(int chr) BA_CXX_NOEXCEPT;
+int puts(const char* str) BA_CXX_NOEXCEPT;
+int printf(const char* format, ...) BA_CXX_NOEXCEPT;
+
+BA_EXTERN_C_END
+
+#endif // !defined(BAD_APPLE_OS_STDIO_H_INCLUDED)

include/stdlib.h

@@ -0,0 +1,15 @@
+
+#pragma once
+
+#if !defined(BAD_APPLE_OS_STDLIB_H_INCLUDED)
+#define BAD_APPLE_OS_STDLIB_H_INCLUDED
+
+#include "./detail/common.h"
+
+BA_EXTERN_C_BEGIN
+
+BA_CXX_NORETURN void abort();
+
+BA_EXTERN_C_END
+
+#endif // !defined(BAD_APPLE_OS_STDLIB_H_INCLUDED)

include/string.h

@@ -6,14 +6,16 @@
 
 #include <stddef.h>
 
-#include "./detail/attributes.h"
+#include "./detail/common.h"
 
-#if defined(__cplusplus)
-extern "C" {
-#endif
+BA_EXTERN_C_BEGIN
+
+BA_CXX_NODISCARD int memcmp(const void* lhs, const void* rhs, size_t count) BA_CXX_NOEXCEPT;
+void memcpy(void* dest, const void* src, size_t count) BA_CXX_NOEXCEPT;
+void memmove(void* dest, const void* src, size_t count) BA_CXX_NOEXCEPT;
+void* memset(void* dest, int value, size_t count) BA_CXX_NOEXCEPT;
 BA_CXX_NODISCARD size_t strlen(const char* str) BA_CXX_NOEXCEPT;
-#if defined(__cplusplus)
-}
-#endif
+
+BA_EXTERN_C_END
 
 #endif // !defined(BAD_APPLE_OS_STRING_H_INCLUDED)

src/app/main.cpp

@@ -0,0 +1,17 @@
+
+#include <cstdio>
+
+#include <cassert>
+
+extern "C" void main()
+{
+    std::puts("Hello, kernel World!");
+
+    while (true)
+    {
+        for (char chr = 'A'; chr <= 'Z'; ++chr)
+        {
+            std::printf("char: %c", chr);
+        }
+    }
+}

src/kernel/startup.cpp

@@ -1,29 +1,12 @@
 
 #include "os/tty.hpp"
 
-/* Check if the compiler thinks you are targeting the wrong operating system. */
-#if defined(__linux__)
-#error "You are not using a cross-compiler, you will most certainly run into trouble"
-#endif
- 
-/* This tutorial will only work for the 32-bit ix86 targets. */
-#if !defined(__i386__)
-#error "This tutorial needs to be compiled with a ix86-elf compiler"
-#endif
+extern "C" void main();
 
 extern "C" void kernel_main(void) 
 {
 	/* Initialize terminal interface */
 	tty::initialize();
 
-	tty::write("Hello, kernel World!\n");
-
-    while (true)
-    {
-        for (char chr = 'A'; chr <= 'Z'; ++chr)
-        {
-            char buf[2] = {chr, '\n'};
-            tty::write(buf, 2);
-        }
-    }
+    main();
 }

src/os/tty.cpp

@@ -35,16 +35,7 @@ void newline()
     else
     {
         // scrolling up
-        for (size_t y = 0; y < VGA_HEIGHT - 1; ++y)
-        {
-            // TODO: this is where I'd put my memcpy. If I had one.
-            for (size_t x = 0; x < VGA_WIDTH; ++x)
-            {
-                const size_t indexTo = y * VGA_WIDTH + x;
-                const size_t indexFrom = (y + 1) * VGA_WIDTH + x;
-                gTerminalBuffer[indexTo] = gTerminalBuffer[indexFrom];
-            }
-        }
+        std::memmove(&gTerminalBuffer[0], &gTerminalBuffer[VGA_WIDTH], VGA_WIDTH * (VGA_HEIGHT - 1) * sizeof(uint16_t));
     }
 }
 }
@@ -74,6 +65,12 @@ void putEntryAt(char chr, VgaDoubleColor color, size_t posX, size_t posY)
 
 void putChar(char chr)
 {
+    if (chr == '\n')
+    {
+        newline();
+        return;
+    }
+
     putEntryAt(chr, gTerminalColor, gTerminalColumn, gTerminalRow);
     if (++gTerminalColumn == VGA_WIDTH)
     {
@@ -85,14 +82,7 @@ void write(const char* data, size_t size)
 {
     for (size_t idx = 0; idx < size; idx++)
     {
-        if (data[idx] == '\n')
-        {
-            newline();
-        }
-        else
-        {
-            putChar(data[idx]);
-        }
+        putChar(data[idx]);
     }
 }
 

src/stdlib/assert.cpp

@@ -0,0 +1,20 @@
+
+#include <assert.h>
+
+#include <cstdio>
+#include <cstdlib>
+
+extern "C"
+{
+#if !defined(NDEBUG)
+void __ba__assert_fail(const char* filename, int line, const char* condition) noexcept
+{
+    std::printf(R"(
+Assertion failed:
+File:      %s
+Line:      %d
+Condition: %s)", filename, line, condition);
+    std::abort();
+}
+#endif
+} // extern "C"

src/stdlib/stdio.cpp

@@ -0,0 +1,118 @@
+
+#include <stdio.h>
+
+#include <cassert>
+#include <cstring>
+#include <stdarg.h>
+#include "os/tty.hpp"
+
+extern "C"
+{
+namespace
+{
+int printInt(int value)
+{
+    if (value == 0)
+    {
+        putchar('0');
+        return 1;
+    }
+    if (value < 0)
+    {
+        putchar('-');
+        return printInt(-value) + 1;
+    }
+
+    char digits[10]; // 2147483647 has 10 digits
+    char* pos = &digits[0];
+
+    while (value > 0)
+    {
+        *pos = static_cast<char>('0' + (value % 10));
+        value /= 10;
+        ++pos;
+    }
+    for (char* chr = pos - 1; chr >= digits; --chr)
+    {
+        putchar(*chr);
+    }
+    return pos - digits;
+}
+}
+
+int putchar(int chr) noexcept
+{
+    tty::putChar(static_cast<char>(chr));
+    return 0;
+}
+
+int puts(const char* str) noexcept
+{
+    tty::write(str);
+    tty::putChar('\n');
+    return 0;
+}
+
+int printf(const char* format, ...) noexcept
+{
+    va_list parameters;
+    va_start(parameters, format);
+
+    int result = 0;
+    const char* pos = format;
+    while (*pos != '\0')
+    {
+        if (*pos == '%')
+        {
+            ++pos;
+            switch (*pos)
+            {
+                case '%':
+                    putchar('%');
+                    ++result;
+                    break;
+                case '\0':
+                    // TODO: invalid format string, do something
+                    assert(!"Invalid format string, ends with %.");
+                    va_end(parameters);
+                    return -1;
+                case 'c':
+                {
+                    const char chr = static_cast<char>(va_arg(parameters, int));
+                    putchar(chr);
+                    ++result;
+                    break;
+                }
+                case 's':
+                {
+                    const char* str = va_arg(parameters, const char*);
+                    const size_t len = std::strlen(str);
+
+                    for (size_t idx = 0; idx < len; ++idx)
+                    {
+                        putchar(str[idx]);
+                    }
+                    result += static_cast<int>(len);
+                    break;
+                }
+                case 'd':
+                    result += printInt(va_arg(parameters, int));
+                    break;
+                default:
+                    assert(!"Invalid format string, unknown format identifier.");
+                    va_end(parameters);
+                    return -1;
+            }
+        } else
+        {
+            putchar(*pos);
+        }
+        ++pos;
+    }
+    va_end(parameters);
+    putchar('\n');
+    ++result;
+    return result;
+}
+} // extern "C"
+

src/stdlib/stdlib.cpp

@@ -0,0 +1,12 @@
+
+#include <stdlib.h>
+
+extern "C"
+{
+void abort()
+{
+    __asm__ volatile("hlt");
+    while(true) {};
+    __builtin_unreachable();
+}
+} // extern "C"

src/stdlib/string.cpp

@@ -1,8 +1,59 @@
 
 #include <string.h>
 
+#include <stdint.h>
+
 extern "C"
 {
+int memcmp(const void* lhs, const void* rhs, size_t count) noexcept
+{
+    for (size_t pos = 0; pos < count; ++pos)
+    {
+        const unsigned char left = *(static_cast<const unsigned char*>(lhs) + pos);
+        const unsigned char right = *(static_cast<const unsigned char*>(rhs) + pos);
+
+        if (left != right) {
+            return left - right;
+        }
+    }
+    return 0;
+}
+
+void memcpy(void* dest, const void* src, size_t count) noexcept
+{
+    for (size_t pos = 0; pos < count; ++pos)
+    {
+        *(static_cast<uint8_t*>(dest) + pos) = *(static_cast<const uint8_t*>(src) + pos);
+    }
+}
+
+void memmove(void* dest, const void* src, size_t count) noexcept
+{
+    if (dest < src)
+    {
+        for (size_t pos = 0; pos < count; ++pos)
+        {
+            *(static_cast<uint8_t*>(dest) + pos) = *(static_cast<const uint8_t*>(src) + pos);
+        }
+    }
+    else
+    {
+        for (size_t pos = 0; pos < count; ++pos)
+        {
+            *(static_cast<uint8_t*>(dest) + count - pos - 1) = *(static_cast<const uint8_t*>(src) + count - pos - 1);
+        }
+    }
+}
+
+void* memset(void* dest, int value, size_t count) noexcept
+{
+    for (size_t pos = 0; pos < count; ++pos)
+    {
+        *(static_cast<unsigned char*>(dest) + pos) = static_cast<unsigned char>(value);
+    }
+    return dest;
+}
+
 size_t strlen(const char* str) noexcept
 {
     size_t len = 0;