Fixing the memory, adding a shell, and other minor bugs to gdt and idt and the types, also adds .github files for bug reports and feature requests.

src/drivers/io/io.c

@@ -0,0 +1,51 @@
+#include "io.h"
+
+/*
+    Common Ports 
+    COM1: 0x3F8
+    COM2: 0x2F8
+    COM3: 0x3E8
+    COM4: 0x2E8
+    LPT1: 0x378
+    LPT2: 0x278
+    LPT3: 0x3BC
+*/
+
+// Function to initialize the COM and LPT ports
+void io_init()
+{
+    // TODO: Initialize the COM and LPT ports
+    // Set up any necessary configuration or control operations
+}
+
+// Function to read from the COM port
+char io_read_com()
+{
+    // TODO: Read from the COM port
+    // Use the appropriate memory or I/O address to read from the port
+    // Return the read data
+}
+
+// Function to write to the COM port
+void io_write_com(char data)
+{
+    // TODO: Write to the COM port
+    // Use the appropriate memory or I/O address to write to the port
+    // Write the provided data to the port
+}
+
+// Function to read from the LPT port
+char io_read_lpt()
+{
+    // TODO: Read from the LPT port
+    // Use the appropriate memory or I/O address to read from the port
+    // Return the read data
+}
+
+// Function to write to the LPT port
+void io_write_lpt(char data)
+{
+    // TODO: Write to the LPT port
+    // Use the appropriate memory or I/O address to write to the port
+    // Write the provided data to the port
+}

src/drivers/io/io.h

@@ -0,0 +1,19 @@
+#ifndef IO_H
+#define IO_H
+
+// Function to initialize the COM and LPT ports
+void io_init();
+
+// Function to read from the COM port
+char io_read_com();
+
+// Function to write to the COM port
+void io_write_com(char data);
+
+// Function to read from the LPT port
+char io_read_lpt();
+
+// Function to write to the LPT port
+void io_write_lpt(char data);
+
+#endif /* IO_H */

src/kernel/arch/x86/gdt.c

@@ -1,5 +1,5 @@
 #include "gdt.h"
-
+#include <string.h>
 // GDT table
 struct gdt_entry gdt[3];
 
@@ -36,7 +36,7 @@ void gdt_init()
     gdt_set_gate(2, 0, 0xFFFFFFFF, 0x92, 0xCF);
 
     // Load GDT
-    asm volatile("lgdt %0" : : "m"(gp));
+    _asm volatile("lgdt %0" : : "m"(gp));
 }
 
 // Exception handlers

src/kernel/arch/x86/idt.c

@@ -1,9 +1,16 @@
 #include "idt.h"
+#include <string.h>
 
 // IDT table
 struct idt_entry idt[256];
 
 // IDT pointer
+struct idt_ptr
+{
+    uint16_t          limit; // Size of IDT in bytes - 1
+    struct idt_entry *base;  // Address of IDT
+} __attribute__((packed));
+
 struct idt_ptr idtp;
 
 // Exception handlers
@@ -33,7 +40,7 @@ void idt_init()
 {
     // Set up IDT pointer
     idtp.limit = sizeof(idt) - 1;
-    idtp.base  = (uint32_t)&idt;
+    idtp.base  = idt;
 
     // Clear IDT
     memset(&idt, 0, sizeof(idt));
@@ -51,5 +58,5 @@ void idt_init()
     idt_set_gate(0x30, (uint32_t)device_handler, 0x08, 0x8E);
 
     // Load IDT
-    asm volatile("lidt %0" : : "m"(idtp));
+    _asm volatile("lidt %0" : : "m"(idtp));
 }

src/kernel/arch/x86/include/memory.h

@@ -1,8 +1,10 @@
 #ifndef MEMORY_H
 #define MEMORY_H
 
+#include <stddef.h>
 #include <stdint.h>
 
+void  init_heap(void *start, size_t size);
 void *kmalloc(size_t size);
 void  kfree(void *ptr);
 

src/kernel/arch/x86/include/types.h

@@ -1,19 +1,24 @@
 #ifndef TYPES_H
 #define TYPES_H
 
-typedef unsigned char uint8_t;
+typedef unsigned char  uint8_t;
 typedef unsigned short uint16_t;
-typedef unsigned int uint32_t;
+typedef unsigned int   uint32_t;
 
-typedef struct {
+typedef struct
+{
     uint32_t base;
     uint32_t limit;
     uint16_t flags;
 } gdt_entry_t;
 
-typedef struct {
-    uint16_t limit;
-    uint32_t base;
+typedef struct
+{
+    uint16_t base_lo;  // Lower 16 bits of handler function address
+    uint16_t selector; // Kernel segment selector
+    uint8_t  always0;  // Always 0
+    uint8_t  flags;    // Flags
+    uint16_t base_hi;  // Upper 16 bits of handler function address
 } idt_entry_t;
 
 #endif /* TYPES_H */

src/kernel/arch/x86/memory/memory.c

@@ -1,12 +1,54 @@
 #include "../include/memory.h"
+#include <stddef.h>
+#include <string.h>
+
+/* The start of the kernel heap */
+static uint8_t *heap_start = NULL;
+
+/* The end of the kernel heap */
+static uint8_t *heap_end = NULL;
+
+/* The current position of the heap */
+static uint8_t *heap_pos = NULL;
+
+/* The size of the heap */
+static size_t heap_size = 0;
+
+void init_heap(void *start, size_t size)
+{
+    heap_start = (uint8_t *)start;
+    heap_end   = heap_start + size;
+    heap_pos   = heap_start;
+    heap_size  = size;
+}
 
 void *kmalloc(size_t size)
 {
-    /* TODO: Implement memory allocation */
-    return NULL;
+    /* Round up the size to a multiple of 4 bytes */
+    size = (size + 3) & ~3;
+
+    /* Check if there is enough space in the heap */
+    if (heap_pos + size > heap_end)
+    {
+        return NULL;
+    }
+
+    /* Allocate memory from the heap */
+    void *ptr = heap_pos;
+    heap_pos += size;
+
+    return ptr;
 }
 
 void kfree(void *ptr)
 {
-    /* TODO: Implement memory deallocation */
-}
+    /* Check if the pointer is within the heap */
+    if ((uint8_t *)ptr >= heap_start && ptr < (void *)heap_end)
+    {
+        /* Zero out the memory */
+        memset(ptr, 0, (uint8_t *)heap_pos - (uint8_t *)ptr);
+
+        /* Free the memory by moving the heap position */
+        heap_pos = (uint8_t *)ptr;
+    }
+}

src/shell/shell.c

@@ -0,0 +1,32 @@
+#include "shell.h"
+#include <stdio.h>
+#include <string.h>
+
+void shell_loop()
+{
+    char input[256];
+
+    while (1)
+    {
+        printf("> ");
+        fgets(input, sizeof(input), stdin);
+
+        // Remove newline character from input
+        input[strcspn(input, "\n")] = '\0';
+
+        // Parse input and execute commands
+        // ...
+
+        // Exit the shell if the user enters "exit"
+        if (strcmp(input, "exit") == 0)
+        {
+            break;
+        }
+    }
+}
+
+int main()
+{
+    shell_loop();
+    return 0;
+}

src/shell/shell.h

@@ -0,0 +1,13 @@
+#ifndef SHELL_H
+#define SHELL_H
+
+// Function to read user input
+char *read_input();
+
+// Function to parse user input
+char **parse_input(char *input);
+
+// Function to execute a command
+int execute_command(char **args);
+
+#endif