Cleanup and refactoring

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "files.associations": {
+        "ktypes.h": "c"
+    }
+}

build-cross-compiler.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+mkdir /tmp/src
+cd /tmp/src
+curl -O http://ftp.gnu.org/gnu/binutils/binutils-2.39.tar.gz
+tar xf binutils-2.39.tar.gz
+mkdir binutils-build
+cd binutils-build
+../binutils-2.39/configure --target=$TARGET --enable-interwork --enable-multilib --disable-nls --disable-werror --prefix=$PREFIX 2>&1 | tee configure.log
+sudo make all install 2>&1 | tee make.log
+cd /tmp/src
+curl -O https://ftp.gnu.org/gnu/gcc/gcc-12.2.0/gcc-12.2.0.tar.gz
+tar xf gcc-12.2.0.tar.gz
+mkdir gcc-build
+cd gcc-build
+../gcc-12.2.0/configure --target=$TARGET --prefix="$PREFIX" --disable-nls --disable-libssp --enable-languages=c --without-headers
+sudo make all-gcc 
+sudo make all-target-libgcc 
+sudo make install-gcc 
+sudo make install-target-libgcc 

build.sh

@@ -1,5 +1,6 @@
 #!/bin/bash
-i386-elf-gcc -ffreestanding -c src/kernel/main.c -o main.o
-nasm -f elf src/entrypoint.s -o entrypoint.o
-i386-elf-ld -o kernel.bin -Ttext 0x1000 entrypoint.o main.o --oformat binary
+i386-elf-gcc -ffreestanding -c src/kernel/main.c -o kernel.o
+nasm -f elf src/entrypoint.s -o entry.o
+nasm -f bin src/boot/mbr.s -o mbr.bin
+i386-elf-ld -o kernel.bin -Ttext 0x1000 entry.o kernel.o --oformat binary
 cat mbr.bin kernel.bin > os.bin

env.sh

@@ -3,4 +3,4 @@ export CC=/usr/bin/gcc
 export LD=/usr/bin/gcc
 export PREFIX="/usr/local/i386elfgcc"
 export TARGET=i386-elf
-export PATH="$PREFIX/bin:$PATH"
+export PATH=$PATH:$PREFIX/bin

src/boot/mbr.s

@@ -25,10 +25,10 @@ jmp $ ; Keeps jumping at the current address (loops forever)
 
 ; Now we include our "function definitions" (after the 
 ; loop, so they're never executed unless explicitly called)
-%include "src/bootloader/util/disk.s"
-%include "src/bootloader/util/io.s"
-%include "src/bootloader/gdt.s"
-%include "src/bootloader/switch32.s"
+%include "src/boot/util/disk.s"
+%include "src/boot/util/io.s"
+%include "src/boot/gdt.s"
+%include "src/boot/switch32.s"
 
 [bits 16]       ; All x86 CPUs start in 16 bit (aka "real") mode, so we tell nasm to emit 16-bit code
 load_kernel:    ; Loads the kernel into memory

src/kernel/drivers/vga/video.c

@@ -0,0 +1,30 @@
+// Implementation of a simple video driver using VGA text mode
+#include "video.h"
+
+
+uchar_t vga_readb(u16_t port) {
+    // Reads a byte from the specified I/O port
+    uchar_t result;
+    __asm__("in %%dx, %%al" : "=a" (result) : "d" (port));
+    return result;
+}
+
+
+void vga_writeb(u16_t port, uchar_t data) {
+    // Writes a byte from the specified I/O port
+    __asm__("out %%al, %%dx" : : "a" (data), "d" (port));
+}
+
+
+u16_t vga_writew(u16_t port) {
+    // Reads a word (16 bits) from the specified I/O port
+    u16_t result;
+    __asm__("in %%dx, %%ax" : "=a" (result) : "d" (port));
+    return result;
+}
+
+
+void vga_readw(u16_t port, u16_t data) {
+    // Writes a word (16 bits) to the specified I/O port
+    __asm__("out %%ax, %%dx" : : "a" (data), "d" (port));
+}

src/kernel/drivers/vga/video.h

@@ -0,0 +1,14 @@
+#ifndef TSOS_DRV_VGA_H  // Avoid nasty double-inclusion problems
+#define TSOS_DRV_VGA_H
+#define VMEM_ADDR 0xb8000
+#include "kernel/types/ktypes.h"
+
+
+uchar_t vga_writeb(u16_t port);
+void vga_readb(u16_t port, uchar_t data);
+u16_t vga_writew(u16_t port);
+void vga_readw(u16_t port, u16_t data);
+
+
+
+#endif

src/kernel/main.c

@@ -1,15 +1,12 @@
-// C entry point of our kernel
-#define VMEM_ADDR 0xb8000
-
-void dummy_test_entrypoint(void) {
-}
+// Entry point of the TSOS kernel
+#include "types/ktypes.h"
 
 
 void kmain(void) {
-    char* vbuf = (char*)VMEM_ADDR;
+    char_t* vbuf = (char_t*)0xb8000;
     vbuf += 480;    // We skip the log messages before us
-    char *s = "Hello from the TSOS kernel!";
-    for (int i = 0; s[i] != '\0'; i++) {
+    char_t *s = "Hello from the TSOS kernel!";
+    for (int_t i = 0; s[i] != '\0'; i++) {
         *vbuf = s[i];
         vbuf += 2;
     }

src/kernel/types/ktypes.h

@@ -0,0 +1,15 @@
+// Shorthand definitions of various types
+// used in the kernel
+#ifndef TSOS_KTYPES
+#define TSOS_KTYPES
+
+
+typedef unsigned char uchar_t;
+typedef unsigned short int u16_t;
+typedef short int i16_t;
+typedef char char_t;
+typedef unsigned int uint_t;
+typedef int int_t;
+
+
+#endif