Create pic.c

Implementation for pic.h

kernel/cmos.c

@@ -1,86 +0,0 @@
-#include "cmos.h"
-#include "io.h"
-#include "print.h"
-
-#define CMOS_ADDR 0x70
-#define CMOS_DATA 0x71
-
-enum {
-    CMOS_SEC  = 0x00,
-    CMOS_MIN  = 0x02,
-    CMOS_HOUR = 0x04,
-    CMOS_DAY  = 0x07,
-    CMOS_MONTH= 0x08,
-    CMOS_YEAR = 0x09,
-    CMOS_STAT_A = 0x0A,
-    CMOS_STAT_B = 0x0B
-};
-
-// Check if CMOS is currently updating its values
-static int is_updating() {
-    outb(CMOS_ADDR, CMOS_STAT_A);
-    return (inb(CMOS_DATA) & 0x80);
-}
-
-static uint8_t get_register(int reg) {
-    outb(CMOS_ADDR, reg);
-    return inb(CMOS_DATA);
-}
-
-void cmos_read_time(cmos_time_t* time) {
-    // Wait for any current update to finish
-    while (is_updating());
-
-    uint8_t sec   = get_register(CMOS_SEC);
-    uint8_t min   = get_register(CMOS_MIN);
-    uint8_t hour  = get_register(CMOS_HOUR);
-    uint8_t day   = get_register(CMOS_DAY);
-    uint8_t month = get_register(CMOS_MONTH);
-    uint8_t year  = get_register(CMOS_YEAR);
-    uint8_t statb = get_register(CMOS_STAT_B);
-
-    // If Bit 2 of Status Register B is 0, then values are BCD
-    if (!(statb & 0x04)) {
-        time->second = (sec & 0x0F) + ((sec / 16) * 10);
-        time->minute = (min & 0x0F) + ((min / 16) * 10);
-        time->hour   = ((hour & 0x0F) + (((hour & 0x70) / 16) * 10)) | (hour & 0x80);
-        time->day    = (day & 0x0F) + ((day / 16) * 10);
-        time->month  = (month & 0x0F) + ((month / 16) * 10);
-        time->year   = (year & 0x0F) + ((year / 16) * 10);
-    } else {
-        time->second = sec;
-        time->minute = min;
-        time->hour   = hour;
-        time->day    = day;
-        time->month  = month;
-        time->year   = year;
-    }
-
-    // Adjust for Century (assuming we are in the 2000s for ClassicOS)
-    time->year += 2000; 
-}
-
-void cmos_print_time(cmos_time_t* time) {
-    // Using your print_string/itoa style logic
-    char buf[16];
-    
-    print_string("System Time: ");
-    
-    // Simple padding check for minutes
-    print_hex(time->hour, 0, 1);
-    print_string(":");
-    if (time->minute < 10) print_string("0");
-    print_hex(time->minute, 0, 1);
-    print_string(":");
-    if (time->second < 10) print_string("0");
-    print_hex(time->second, 0, 1);
-    
-    print_string("  ");
-    
-    print_hex(time->month, 0, 1);
-    print_string("/");
-    print_hex(time->day, 0, 1);
-    print_string("/");
-    print_hex(time->year, 0, 1);
-    print_string("\n");
-}

kernel/cmos.h

@@ -1,18 +0,0 @@
-#ifndef CMOS_H
-#define CMOS_H
-
-#include <stdint.h>
-
-typedef struct {
-    uint8_t second;
-    uint8_t minute;
-    uint8_t hour;
-    uint8_t day;
-    uint8_t month;
-    uint32_t year;
-} cmos_time_t;
-
-void cmos_read_time(cmos_time_t* time);
-void cmos_print_time(cmos_time_t* time);
-
-#endif

kernel/pci.c

@@ -1,109 +0,0 @@
-#include "pci.h"
-#include "io.h"
-
-/* --- Configuration Access Functions --- */
-
-uint32_t pci_config_read_dword(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset) {
-    uint32_t address = (uint32_t)((uint32_t)1 << 31) | 
-                       ((uint32_t)bus << 16) | 
-                       ((uint32_t)slot << 11) | 
-                       ((uint32_t)func << 8) | 
-                       (offset & 0xFC);
-    outl(PCI_CONFIG_ADDRESS, address);
-    return inl(PCI_CONFIG_DATA);
-}
-
-void pci_config_write_dword(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset, uint32_t data) {
-    uint32_t address = (uint32_t)((uint32_t)1 << 31) | 
-                       ((uint32_t)bus << 16) | 
-                       ((uint32_t)slot << 11) | 
-                       ((uint32_t)func << 8) | 
-                       (offset & 0xFC);
-    outl(PCI_CONFIG_ADDRESS, address);
-    outl(PCI_CONFIG_DATA, data);
-}
-
-/* To read a word or byte, we read the Dword and shift/mask */
-uint16_t pci_config_read_word(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset) {
-    uint32_t dword = pci_config_read_dword(bus, slot, func, offset);
-    return (uint16_t)((dword >> ((offset & 2) * 8)) & 0xFFFF);
-}
-
-uint8_t pci_config_read_byte(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset) {
-    uint32_t dword = pci_config_read_dword(bus, slot, func, offset);
-    return (uint8_t)((dword >> ((offset & 3) * 8)) & 0xFF);
-}
-
-/* --- BAR Decoding Logic --- */
-
-pci_bar_t pci_get_bar(uint8_t bus, uint8_t slot, uint8_t func, uint8_t bar_index) {
-    pci_bar_t bar = {0};
-    uint8_t offset = PCI_REG_BAR0 + (bar_index * 4);
-    
-    uint32_t initial_val = pci_config_read_dword(bus, slot, func, offset);
-    
-    // The Size Masking Trick
-    pci_config_write_dword(bus, slot, func, offset, 0xFFFFFFFF);
-    uint32_t mask = pci_config_read_dword(bus, slot, func, offset);
-    pci_config_write_dword(bus, slot, func, offset, initial_val); // Restore
-    
-    if (initial_val & 0x1) {
-        // I/O Space BAR
-        bar.is_io = true;
-        bar.base_address = initial_val & 0xFFFFFFFC;
-        bar.size = ~(mask & 0xFFFFFFFC) + 1;
-    } else {
-        // Memory Space BAR
-        bar.is_io = false;
-        bar.base_address = initial_val & 0xFFFFFFF0;
-        bar.is_prefetchable = (initial_val & 0x8) != 0;
-        bar.size = ~(mask & 0xFFFFFFF0) + 1;
-    }
-    
-    return bar;
-}
-
-/* --- Enumeration and Discovery --- */
-
-void pci_check_function(uint8_t bus, uint8_t slot, uint8_t func) {
-    uint16_t vendor_id = pci_config_read_word(bus, slot, func, PCI_REG_VENDOR_ID);
-    if (vendor_id == 0xFFFF) return; 
-
-    uint16_t device_id = pci_config_read_word(bus, slot, func, PCI_REG_DEVICE_ID);
-    uint8_t class_code = pci_config_read_byte(bus, slot, func, PCI_REG_CLASS);
-    
-    /* Optional: Set Master Latency Timer if it is 0. 
-       A value of 32 (0x20) or 64 (0x40) is typical. 
-    */
-    uint8_t latency = pci_config_read_byte(bus, slot, func, PCI_REG_LATENCY_TIMER);
-    if (latency == 0) {
-        // pci_config_write_byte would be needed here, or write a dword with the byte modified
-        uint32_t reg_0c = pci_config_read_dword(bus, slot, func, 0x0C);
-        reg_0c |= (0x20 << 8); // Set latency to 32
-        pci_config_write_dword(bus, slot, func, 0x0C, reg_0c);
-    }
-
-    // Replace with your kernel's print/logging function
-    // printf("Found PCI Device: %x:%x Class: %x at %d:%d:%d\n", vendor_id, device_id, class_code, bus, slot, func);
-}
-
-void pci_init(void) {
-    for (uint16_t bus = 0; bus < 256; bus++) {
-        for (uint8_t slot = 0; slot < 32; slot++) {
-            // Check Function 0 first
-            uint16_t vendor = pci_config_read_word(bus, slot, 0, PCI_REG_VENDOR_ID);
-            if (vendor == 0xFFFF) continue;
-
-            pci_check_function(bus, slot, 0);
-
-            // Check if this is a multi-function device
-            uint8_t header_type = pci_config_read_byte(bus, slot, 0, PCI_REG_HEADER_TYPE);
-            if (header_type & 0x80) {
-                // Check functions 1-7
-                for (uint8_t func = 1; func < 8; func++) {
-                    pci_check_function(bus, slot, func);
-                }
-            }
-        }
-    }
-}

kernel/pci.h

@@ -1,60 +0,0 @@
-#ifndef PCI_H
-#define PCI_H
-
-#include <stdint.h>
-#include <stdbool.h>
-
-/* I/O Ports for PCI Configuration Mechanism #1 */
-#define PCI_CONFIG_ADDRESS 0xCF8
-#define PCI_CONFIG_DATA    0xCFC
-
-/* Common PCI Configuration Register Offsets */
-#define PCI_REG_VENDOR_ID       0x00
-#define PCI_REG_DEVICE_ID       0x02
-#define PCI_REG_COMMAND         0x04
-#define PCI_REG_STATUS          0x06
-#define PCI_REG_REVISION_ID     0x08
-#define PCI_REG_PROG_IF         0x09
-#define PCI_REG_SUBCLASS        0x0A
-#define PCI_REG_CLASS           0x0B
-#define PCI_REG_CACHE_LINE_SIZE 0x0C
-#define PCI_REG_LATENCY_TIMER   0x0D
-#define PCI_REG_HEADER_TYPE     0x0E
-#define PCI_REG_BIST            0x0F
-#define PCI_REG_BAR0            0x10
-#define PCI_REG_BAR1            0x14
-#define PCI_REG_BAR2            0x18
-#define PCI_REG_BAR3            0x1C
-#define PCI_REG_BAR4            0x20
-#define PCI_REG_BAR5            0x24
-#define PCI_REG_INTERRUPT_LINE  0x3C
-
-typedef struct {
-    uint32_t base_address;
-    uint32_t size;
-    bool     is_io;
-    bool     is_prefetchable; // Only for Memory BARs
-} pci_bar_t;
-
-typedef struct {
-    uint8_t  bus;
-    uint8_t  device;
-    uint8_t  function;
-    uint16_t vendor_id;
-    uint16_t device_id;
-    uint8_t  class_code;
-    uint8_t  subclass;
-    uint8_t  interrupt_line;
-} pci_dev_t;
-
-/* Function Prototypes */
-uint32_t pci_config_read_dword(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset);
-void     pci_config_write_dword(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset, uint32_t data);
-
-uint16_t pci_config_read_word(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset);
-uint8_t  pci_config_read_byte(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset);
-
-pci_bar_t pci_get_bar(uint8_t bus, uint8_t slot, uint8_t func, uint8_t bar_index);
-void      pci_init(void);
-
-#endif

kernel/pic.h

@@ -0,0 +1,25 @@
+#ifndef PIC_H
+#define PIC_H
+
+#include <stdint.h>
+
+/* I/O Ports for the PICs */
+#define PIC1_COMMAND 0x20
+#define PIC1_DATA    0x21
+#define PIC2_COMMAND 0xA0
+#define PIC2_DATA    0xA1
+
+/* PIC Commands */
+#define PIC_EOI      0x20  /* End of Interrupt */
+
+/* Offset vectors for remapping */
+#define PIC1_OFFSET  0x20
+#define PIC2_OFFSET  0x28
+
+void pic_init(void);
+void pic_send_eoi(uint8_t irq);
+void pic_mask(uint8_t irq);
+void pic_unmask(uint8_t irq);
+void pic_disable(void);
+
+#endif

kernel/ps2.c

@@ -1,107 +0,0 @@
-#include "ps2.h"
-#include "io.h"
-
-/* --- Controller Synchronization --- */
-
-// Wait until the controller is ready to receive a byte
-static void ps2_wait_write() {
-    while (inb(PS2_STATUS_REG) & PS2_STATUS_INPUT);
-}
-
-// Wait until the controller has a byte for us to read
-static void ps2_wait_read() {
-    while (!(inb(PS2_STATUS_REG) & PS2_STATUS_OUTPUT));
-}
-
-/* --- Initialization --- */
-
-void ps2_write_device(uint8_t command) {
-    ps2_wait_write();
-    outb(PS2_DATA_PORT, command);
-}
-
-void ps2_write_mouse(uint8_t data) {
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_WRITE_MOUSE); // "Next byte goes to mouse"
-    ps2_wait_write();
-    outb(PS2_DATA_PORT, data);
-}
-
-void ps2_init(void) {
-    // 1. Disable Devices
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_DISABLE_KB);
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_DISABLE_MS);
-
-    // 2. Flush Output Buffer
-    while (inb(PS2_STATUS_REG) & PS2_STATUS_OUTPUT) {
-        inb(PS2_DATA_PORT);
-    }
-
-    // 3. Set Controller Configuration Byte
-    // Bit 0: KB Interrupt, Bit 1: Mouse Interrupt, Bit 6: Translation
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_READ_CONFIG);
-    ps2_wait_read();
-    uint8_t status = inb(PS2_DATA_PORT);
-    status |= (1 << 0) | (1 << 1); // Enable IRQ 1 and IRQ 12
-    
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_WRITE_CONFIG);
-    ps2_wait_write();
-    outb(PS2_DATA_PORT, status);
-
-    // 4. Enable Devices
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_ENABLE_KB);
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_ENABLE_MS);
-
-    // 5. Initialize Mouse (The mouse won't send IRQs until you tell it to)
-    ps2_write_mouse(MOUSE_CMD_SET_DEFAULTS);
-    ps2_wait_read(); inb(PS2_DATA_PORT); // Read ACK (0xFA)
-    
-    ps2_write_mouse(MOUSE_CMD_ENABLE_SCAN);
-    ps2_wait_read(); inb(PS2_DATA_PORT); // Read ACK (0xFA)
-}
-
-/* --- IRQ Handlers --- */
-
-// Called from IRQ 1 (Keyboard)
-void ps2_keyboard_handler(void) {
-    uint8_t scancode = inb(PS2_DATA_PORT);
-    // Process scancode (e.g., put it into a circular buffer)
-}
-
-// Called from IRQ 12 (Mouse)
-static uint8_t mouse_cycle = 0;
-static uint8_t mouse_bytes[3];
-
-void ps2_mouse_handler(void) {
-    uint8_t status = inb(PS2_STATUS_REG);
-    
-    // Ensure this is actually mouse data
-    if (!(status & PS2_STATUS_MOUSE)) return;
-
-    mouse_bytes[mouse_cycle++] = inb(PS2_DATA_PORT);
-
-    if (mouse_cycle == 3) {
-        mouse_cycle = 0;
-        
-        // Byte 0: Flags (Buttons, Signs)
-        // Byte 1: X Delta
-        // Byte 2: Y Delta
-        
-        mouse_state_t state;
-        state.left_button   = (mouse_bytes[0] & 0x01);
-        state.right_button  = (mouse_bytes[0] & 0x02);
-        state.middle_button = (mouse_bytes[0] & 0x04);
-
-        // Handle negative deltas (signed 9-bit logic)
-        state.x_delta = (int8_t)mouse_bytes[1];
-        state.y_delta = (int8_t)mouse_bytes[2];
-
-        // Update your kernel's internal mouse position here
-    }
-}

kernel/ps2.h

@@ -1,45 +0,0 @@
-#ifndef PS2_H
-#define PS2_H
-
-#include <stdint.h>
-#include <stdbool.h>
-
-/* I/O Ports */
-#define PS2_DATA_PORT       0x60
-#define PS2_STATUS_REG      0x64
-#define PS2_COMMAND_REG     0x64
-
-/* Status Register Bits */
-#define PS2_STATUS_OUTPUT   0x01 // 1 = Data ready to be read
-#define PS2_STATUS_INPUT    0x02 // 1 = Controller busy, don't write yet
-#define PS2_STATUS_SYS      0x04 // System flag
-#define PS2_STATUS_CMD_DATA 0x08 // 0 = Data written to 0x60, 1 = Cmd to 0x64
-#define PS2_STATUS_MOUSE    0x20 // 1 = Mouse data, 0 = Keyboard data
-
-/* Controller Commands */
-#define PS2_CMD_READ_CONFIG  0x20
-#define PS2_CMD_WRITE_CONFIG 0x60
-#define PS2_CMD_DISABLE_MS   0xA7
-#define PS2_CMD_ENABLE_MS    0xA8
-#define PS2_CMD_DISABLE_KB   0xAD
-#define PS2_CMD_ENABLE_KB    0xAE
-#define PS2_CMD_WRITE_MOUSE  0xD4
-
-/* Mouse Commands */
-#define MOUSE_CMD_SET_DEFAULTS 0xF6
-#define MOUSE_CMD_ENABLE_SCAN  0xF4
-
-typedef struct {
-    int8_t  x_delta;
-    int8_t  y_delta;
-    bool    left_button;
-    bool    right_button;
-    bool    middle_button;
-} mouse_state_t;
-
-/* Public API */
-void ps2_init(void);
-void ps2_keyboard_handler(void);
-void ps2_mouse_handler(void);
-
-#endif

kernel/threading.c

@@ -4,8 +4,8 @@
 #include "print.h"
 #include "threading.h"
 
-#define MAX_THREADS 16          // Maximum number of threads
-#define THREAD_STACK_SIZE 8192  // Stack size for each thread
+#define MAX_THREADS 16           // Maximum number of threads
+#define THREAD_STACK_SIZE 8192   // Stack size for each thread
 
 // The thread table stores information about all threads
 static Thread thread_table[MAX_THREADS];
@@ -16,106 +16,103 @@ static uint32_t num_threads = 0;     // Number of active threads
 static volatile int mutex_locked = 0;
 
 // Function declaration for context_switch
-void context_switch(Thread* next);
+void context_switch(Thread *next);
 
 // Initialize the threading system
 void thread_init(void) {
-  memset(thread_table, 0, sizeof(thread_table));
-  num_threads = 0;
+    memset(thread_table, 0, sizeof(thread_table));
+    num_threads = 0;
 }
 
 // Create a new thread
-void thread_create(Thread* thread __attribute__((unused)),
-                   void (*start_routine)(void*), void* arg) {
-  if (num_threads >= MAX_THREADS) {
-    my_printf("Error: Maximum thread count reached.\n");
-    return;
-  }
+void thread_create(Thread *thread __attribute__((unused)), void (*start_routine)(void *), void *arg) {
+    if (num_threads >= MAX_THREADS) {
+        my_printf("Error: Maximum thread count reached.\n");
+        return;
+    }
 
-  // Find an empty slot for the new thread
-  int index = num_threads++;
-  thread_table[index] = (Thread){0};
+    // Find an empty slot for the new thread
+    int index = num_threads++;
+    thread_table[index] = (Thread){0};
+    
+    // Set up the new thread
+    thread_table[index].start_routine = start_routine;
+    thread_table[index].arg = arg;
+    thread_table[index].stack_size = THREAD_STACK_SIZE;
+    thread_table[index].stack = (uint32_t*)malloc(THREAD_STACK_SIZE);
+    thread_table[index].stack_top = thread_table[index].stack + THREAD_STACK_SIZE / sizeof(uint32_t);
 
-  // Set up the new thread
-  thread_table[index].start_routine = start_routine;
-  thread_table[index].arg = arg;
-  thread_table[index].stack_size = THREAD_STACK_SIZE;
-  thread_table[index].stack = (uint32_t*)malloc(THREAD_STACK_SIZE);
-  thread_table[index].stack_top =
-      thread_table[index].stack + THREAD_STACK_SIZE / sizeof(uint32_t);
+    // Initialize the stack (simulate pushing the function's return address)
+    uint32_t *stack_top = thread_table[index].stack_top;
+    *(--stack_top) = (uint32_t)start_routine;  // Return address (the thread's entry point)
+    *(--stack_top) = (uint32_t)arg;            // Argument to pass to the thread
 
-  // Initialize the stack (simulate pushing the function's return address)
-  uint32_t* stack_top = thread_table[index].stack_top;
-  *(--stack_top) =
-      (uint32_t)start_routine;     // Return address (the thread's entry point)
-  *(--stack_top) = (uint32_t)arg;  // Argument to pass to the thread
+    // Set the thread's state to ready
+    thread_table[index].state = THREAD_READY;
 
-  // Set the thread's state to ready
-  thread_table[index].state = THREAD_READY;
-
-  // If this is the first thread, switch to it
-  if (index == 0) {
-    scheduler();
-  }
+    // If this is the first thread, switch to it
+    if (index == 0) {
+        scheduler();
+    }
 }
 
 // Yield the CPU to another thread
 void thread_yield(void) {
-  // Find the next thread in a round-robin manner
-  uint32_t next_thread = (current_thread + 1) % num_threads;
-  while (next_thread != current_thread &&
-         thread_table[next_thread].state != THREAD_READY) {
-    next_thread = (next_thread + 1) % num_threads;
-  }
+    // Find the next thread in a round-robin manner
+    uint32_t next_thread = (current_thread + 1) % num_threads;
+    while (next_thread != current_thread && thread_table[next_thread].state != THREAD_READY) {
+        next_thread = (next_thread + 1) % num_threads;
+    }
 
-  if (next_thread != current_thread) {
-    current_thread = next_thread;
-    scheduler();
-  }
+    if (next_thread != current_thread) {
+        current_thread = next_thread;
+        scheduler();
+    }
 }
 
 // Exit the current thread
 void thread_exit(void) {
-  thread_table[current_thread].state =
-      THREAD_BLOCKED;  // Mark the thread as blocked (finished)
-  free(thread_table[current_thread].stack);  // Free the thread's stack
-  num_threads--;                             // Decrease thread count
+    thread_table[current_thread].state = THREAD_BLOCKED;  // Mark the thread as blocked (finished)
+    free(thread_table[current_thread].stack);             // Free the thread's stack
+    num_threads--;                                       // Decrease thread count
 
-  // Yield to the next thread
-  thread_yield();
+    // Yield to the next thread
+    thread_yield();
 }
 
 // Scheduler: This function selects the next thread to run
 void scheduler(void) {
-  // Find the next ready thread
-  uint32_t next_thread = (current_thread + 1) % num_threads;
-  while (thread_table[next_thread].state != THREAD_READY) {
-    next_thread = (next_thread + 1) % num_threads;
-  }
+    // Find the next ready thread
+    uint32_t next_thread = (current_thread + 1) % num_threads;
+    while (thread_table[next_thread].state != THREAD_READY) {
+        next_thread = (next_thread + 1) % num_threads;
+    }
 
-  if (next_thread != current_thread) {
-    current_thread = next_thread;
-    context_switch(&thread_table[current_thread]);
-  }
+    if (next_thread != current_thread) {
+        current_thread = next_thread;
+        context_switch(&thread_table[current_thread]);
+    }
 }
 
-// Context switch to the next thread (assembly would go here to save/load
-// registers)
-void context_switch(Thread* next) {
-  // For simplicity, context switching in this example would involve
-  // saving/restoring registers. In a real system, you would need to save the
-  // CPU state (registers) and restore the next thread's state.
-  my_printf("Switching to thread...\n");
-  next->start_routine(next->arg);  // Start running the next thread
+// Context switch to the next thread (assembly would go here to save/load registers)
+void context_switch(Thread *next) {
+    // For simplicity, context switching in this example would involve saving/restoring registers.
+    // In a real system, you would need to save the CPU state (registers) and restore the next thread's state.
+    my_printf("Switching to thread...\n");
+    next->start_routine(next->arg);  // Start running the next thread
 }
 
 // Simple mutex functions (spinlock)
-void mutex_init(void) { mutex_locked = 0; }
-
-void mutex_lock(void) {
-  while (__sync_lock_test_and_set(&mutex_locked, 1)) {
-    // Busy wait (spinlock)
-  }
+void mutex_init(void) {
+    mutex_locked = 0;
 }
 
-void mutex_unlock(void) { __sync_lock_release(&mutex_locked); }
+void mutex_lock(void) {
+    while (__sync_lock_test_and_set(&mutex_locked, 1)) {
+        // Busy wait (spinlock)
+    }
+}
+
+void mutex_unlock(void) {
+    __sync_lock_release(&mutex_locked);
+}

pic.c

@@ -0,0 +1,76 @@
+#include "pic.h"
+#include "io.h"
+
+/* Small delay for older hardware bus timing */
+static inline void io_wait(void) {
+    outb(0x80, 0); 
+}
+
+void pic_init(void) {
+    uint8_t a1, a2;
+
+    // Save current masks
+    a1 = inb(PIC1_DATA);
+    a2 = inb(PIC2_DATA);
+
+    // ICW1: Start initialization in cascade mode
+    outb(PIC1_COMMAND, 0x11);
+    io_wait();
+    outb(PIC2_COMMAND, 0x11);
+    io_wait();
+
+    // ICW2: Master PIC vector offset
+    outb(PIC1_DATA, PIC1_OFFSET);
+    io_wait();
+    // ICW2: Slave PIC vector offset
+    outb(PIC2_DATA, PIC2_OFFSET);
+    io_wait();
+
+    // ICW3: Tell Master there is a slave at IRQ2 (0000 0100)
+    outb(PIC1_DATA, 4);
+    io_wait();
+    // ICW3: Tell Slave its cascade identity (0000 0010)
+    outb(PIC2_DATA, 2);
+    io_wait();
+
+    // ICW4: Set 8086/88 mode
+    outb(PIC1_DATA, 0x01);
+    io_wait();
+    outb(PIC2_DATA, 0x01);
+    io_wait();
+
+    // Restore masks (or disable all to start clean)
+    outb(PIC1_DATA, 0xFB); // Keep IRQ2 (cascade) open
+    outb(PIC2_DATA, 0xFF);
+}
+
+void pic_send_eoi(uint8_t irq) {
+    if (irq >= 8) {
+        outb(PIC2_COMMAND, PIC_EOI);
+    }
+    outb(PIC1_COMMAND, PIC_EOI);
+}
+
+void pic_unmask(uint8_t irq) {
+    uint16_t port;
+    if (irq < 8) {
+        port = PIC1_DATA;
+    } else {
+        port = PIC2_DATA;
+        irq -= 8;
+    }
+    uint8_t value = inb(port) & ~(1 << irq);
+    outb(port, value);
+}
+
+void pic_mask(uint8_t irq) {
+    uint16_t port;
+    if (irq < 8) {
+        port = PIC1_DATA;
+    } else {
+        port = PIC2_DATA;
+        irq -= 8;
+    }
+    uint8_t value = inb(port) | (1 << irq);
+    outb(port, value);
+}