Add interrupts and keyboard driver

scripts/build-kernel.sh

@@ -37,6 +37,7 @@ python3 scripts/embed_js.py build/index.js > "$BUILD_DIR/embedded_js.h"
 
 # Compiler flags
 CFLAGS="-m32 -march=i686 -ffreestanding -nostdlib -fno-builtin"
+CFLAGS="$CFLAGS -mno-sse -mno-sse2 -mno-mmx -mno-3dnow"
 CFLAGS="$CFLAGS -I$PICOLIBC_INSTALL/include"
 CFLAGS="$CFLAGS -I./lib/duktape/src"
 CFLAGS="$CFLAGS -I./src/lib"
@@ -56,10 +57,19 @@ echo "=== Building kernel with picolibc ==="
 echo "Assembling boot code..."
 nasm -f elf32 src/boot/kernel.asm -o "$BUILD_DIR/kasm.o"
 
+# Build interrupt assembly
+echo "Assembling interrupt handlers..."
+nasm -f elf32 src/kernel/interrupt/interrupt.asm -o "$BUILD_DIR/interrupt.o"
+
 # Build duktape
 echo "Building Duktape..."
 gcc $CFLAGS -c lib/duktape/src/duktape.c -o "$BUILD_DIR/duktape.o"
 
+# Build interrupt system
+echo "Building interrupt system..."
+gcc $CFLAGS -c src/kernel/interrupt/idt.c -o "$BUILD_DIR/idt.o"
+gcc $CFLAGS -c src/kernel/interrupt/isr.c -o "$BUILD_DIR/isr.o"
+
 # Build kernel
 echo "Building kernel..."
 gcc $CFLAGS -c src/kernel/kernel.c -o "$BUILD_DIR/kc.o"
@@ -72,6 +82,9 @@ gcc $CFLAGS -c src/lib/syscalls.c -o "$BUILD_DIR/syscalls.o"
 echo "Linking kernel..."
 ld $LDFLAGS -T src/link.ld -o "$OUT_DIR/kernel" \
     "$BUILD_DIR/kasm.o" \
+    "$BUILD_DIR/interrupt.o" \
+    "$BUILD_DIR/idt.o" \
+    "$BUILD_DIR/isr.o" \
     "$BUILD_DIR/kc.o" \
     "$BUILD_DIR/duktape.o" \
     "$BUILD_DIR/syscalls.o" \

src/boot/kernel.asm

@@ -8,10 +8,18 @@ section .text
 
 global start
 extern kmain	;kmain is defined in the kernel.c file
+extern __stack_top
 
 start:
-	cli  ; stop interrupts
+	cli  ; stop interrupts during boot
+	mov esp, __stack_top
+	
+	; Initialize FPU (x87)
+	finit  ; Initialize FPU to default state
 
 	call kmain
+	; Note: kmain will call sti to enable interrupts after IDT is set up
 
-	hlt ; halt the CPU
+hang:
+	hlt ; halt the CPU
+	jmp hang

src/kernel/interrupt/idt.c

@@ -0,0 +1,22 @@
+#include "idt.h"
+
+/* Define the IDT and IDT register here */
+idt_gate_t idt[IDT_ENTRIES];
+idt_register_t idt_reg;
+
+void set_idt_gate(int n, u32 handler)
+{
+  idt[n].low_offset = low_16(handler);
+  idt[n].sel = KERNEL_CS;
+  idt[n].always0 = 0;
+  idt[n].flags = 0x8E;
+  idt[n].high_offset = high_16(handler);
+}
+
+void set_idt()
+{
+  idt_reg.base = (u32)&idt;
+  idt_reg.limit = IDT_ENTRIES * sizeof(idt_gate_t) - 1;
+  /* Don't make the mistake of loading &idt -- always load &idt_reg */
+  __asm__ __volatile__("lidtl (%0)" : : "r"(&idt_reg));
+}

src/kernel/interrupt/idt.h

@@ -0,0 +1,40 @@
+#ifndef IDT_H
+#define IDT_H
+
+#include "types.h"
+
+/* Segment selectors */
+#define KERNEL_CS 0x08
+
+/* How every interrupt gate (handler) is defined */
+typedef struct
+{
+  u16 low_offset; /* Lower 16 bits of handler function address */
+  u16 sel;        /* Kernel segment selector */
+  u8 always0;
+  /* First byte
+   * Bit 7: "Interrupt is present"
+   * Bits 6-5: Privilege level of caller (0=kernel..3=user)
+   * Bit 4: Set to 0 for interrupt gates
+   * Bits 3-0: bits 1110 = decimal 14 = "32 bit interrupt gate" */
+  u8 flags;
+  u16 high_offset; /* Higher 16 bits of handler function address */
+} __attribute__((packed)) idt_gate_t;
+
+/* A pointer to the array of interrupt handlers.
+ * Assembly instruction 'lidt' will read it */
+typedef struct
+{
+  u16 limit;
+  u32 base;
+} __attribute__((packed)) idt_register_t;
+
+#define IDT_ENTRIES 256
+extern idt_gate_t idt[IDT_ENTRIES];
+extern idt_register_t idt_reg;
+
+/* Functions implemented in idt.c */
+void set_idt_gate(int n, u32 handler);
+void set_idt();
+
+#endif

src/kernel/interrupt/interrupt.asm

@@ -0,0 +1,446 @@
+; Defined in isr.c
+[extern isr_handler]
+[extern irq_handler]
+
+; Common ISR code
+isr_common_stub:
+    ; 1. Save CPU state
+	pusha ; Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax
+	mov ax, ds ; Lower 16-bits of eax = ds.
+	push eax ; save the data segment descriptor
+	mov ax, 0x10  ; kernel data segment descriptor
+	mov ds, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+	
+    ; 2. Call C handler - pass pointer to registers_t struct on stack
+	push esp
+	call isr_handler
+	add esp, 4
+	
+    ; 3. Restore state
+	pop eax 
+	mov ds, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+	popa
+	add esp, 8 ; Cleans up the pushed error code and pushed ISR number
+	iret ; pops 5 things at once: CS, EIP, EFLAGS, SS, and ESP (and restores interrupt flag)
+
+; Common IRQ code
+irq_common_stub:
+    ; 1. Save CPU state
+	pusha
+	mov ax, ds
+	push eax
+	mov ax, 0x10
+	mov ds, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+
+    ; 2. Call C handler - pass pointer to registers_t struct on stack
+	push esp
+	call irq_handler
+	add esp, 4
+
+    ; 3. Restore state
+	pop ebx
+	mov ds, bx
+	mov es, bx
+	mov fs, bx
+	mov gs, bx
+	popa
+	add esp, 8
+	iret ; iret restores the interrupt flag automatically from saved EFLAGS
+	
+; We don't get information about which interrupt was caller
+; when the handler is run, so we will need to have a different handler
+; for every interrupt.
+; Furthermore, some interrupts push an error code onto the stack but others
+; don't, so we will push a dummy error code for those which don't, so that
+; we have a consistent stack for all of them.
+
+; First make the ISRs global
+global isr0
+global isr1
+global isr2
+global isr3
+global isr4
+global isr5
+global isr6
+global isr7
+global isr8
+global isr9
+global isr10
+global isr11
+global isr12
+global isr13
+global isr14
+global isr15
+global isr16
+global isr17
+global isr18
+global isr19
+global isr20
+global isr21
+global isr22
+global isr23
+global isr24
+global isr25
+global isr26
+global isr27
+global isr28
+global isr29
+global isr30
+global isr31
+
+; 0: Divide By Zero Exception
+isr0:
+    cli
+    push byte 0
+    push byte 0
+    jmp isr_common_stub
+
+; 1: Debug Exception
+isr1:
+    cli
+    push byte 0
+    push byte 1
+    jmp isr_common_stub
+
+; 2: Non Maskable Interrupt Exception
+isr2:
+    cli
+    push byte 0
+    push byte 2
+    jmp isr_common_stub
+
+; 3: Int 3 Exception
+isr3:
+    cli
+    push byte 0
+    push byte 3
+    jmp isr_common_stub
+
+; 4: INTO Exception
+isr4:
+    cli
+    push byte 0
+    push byte 4
+    jmp isr_common_stub
+
+; 5: Out of Bounds Exception
+isr5:
+    cli
+    push byte 0
+    push byte 5
+    jmp isr_common_stub
+
+; 6: Invalid Opcode Exception
+isr6:
+    cli
+    push byte 0
+    push byte 6
+    jmp isr_common_stub
+
+; 7: Coprocessor Not Available Exception
+isr7:
+    cli
+    push byte 0
+    push byte 7
+    jmp isr_common_stub
+
+; 8: Double Fault Exception (With Error Code!)
+isr8:
+    cli
+    push byte 8
+    jmp isr_common_stub
+
+; 9: Coprocessor Segment Overrun Exception
+isr9:
+    cli
+    push byte 0
+    push byte 9
+    jmp isr_common_stub
+
+; 10: Bad TSS Exception (With Error Code!)
+isr10:
+    cli
+    push byte 10
+    jmp isr_common_stub
+
+; 11: Segment Not Present Exception (With Error Code!)
+isr11:
+    cli
+    push byte 11
+    jmp isr_common_stub
+
+; 12: Stack Fault Exception (With Error Code!)
+isr12:
+    cli
+    push byte 12
+    jmp isr_common_stub
+
+; 13: General Protection Fault Exception (With Error Code!)
+isr13:
+    cli
+    push byte 13
+    jmp isr_common_stub
+
+; 14: Page Fault Exception (With Error Code!)
+isr14:
+    cli
+    push byte 14
+    jmp isr_common_stub
+
+; 15: Reserved Exception
+isr15:
+    cli
+    push byte 0
+    push byte 15
+    jmp isr_common_stub
+
+; 16: Floating Point Exception
+isr16:
+    cli
+    push byte 0
+    push byte 16
+    jmp isr_common_stub
+
+; 17: Alignment Check Exception
+isr17:
+    cli
+    push byte 0
+    push byte 17
+    jmp isr_common_stub
+
+; 18: Machine Check Exception
+isr18:
+    cli
+    push byte 0
+    push byte 18
+    jmp isr_common_stub
+
+; 19: Reserved
+isr19:
+    cli
+    push byte 0
+    push byte 19
+    jmp isr_common_stub
+
+; 20: Reserved
+isr20:
+    cli
+    push byte 0
+    push byte 20
+    jmp isr_common_stub
+
+; 21: Reserved
+isr21:
+    cli
+    push byte 0
+    push byte 21
+    jmp isr_common_stub
+
+; 22: Reserved
+isr22:
+    cli
+    push byte 0
+    push byte 22
+    jmp isr_common_stub
+
+; 23: Reserved
+isr23:
+    cli
+    push byte 0
+    push byte 23
+    jmp isr_common_stub
+
+; 24: Reserved
+isr24:
+    cli
+    push byte 0
+    push byte 24
+    jmp isr_common_stub
+
+; 25: Reserved
+isr25:
+    cli
+    push byte 0
+    push byte 25
+    jmp isr_common_stub
+
+; 26: Reserved
+isr26:
+    cli
+    push byte 0
+    push byte 26
+    jmp isr_common_stub
+
+; 27: Reserved
+isr27:
+    cli
+    push byte 0
+    push byte 27
+    jmp isr_common_stub
+
+; 28: Reserved
+isr28:
+    cli
+    push byte 0
+    push byte 28
+    jmp isr_common_stub
+
+; 29: Reserved
+isr29:
+    cli
+    push byte 0
+    push byte 29
+    jmp isr_common_stub
+
+; 30: Reserved
+isr30:
+    cli
+    push byte 0
+    push byte 30
+    jmp isr_common_stub
+
+; 31: Reserved
+isr31:
+    cli
+    push byte 0
+    push byte 31
+    jmp isr_common_stub
+
+; IRQ handlers
+global irq0
+global irq1
+global irq2
+global irq3
+global irq4
+global irq5
+global irq6
+global irq7
+global irq8
+global irq9
+global irq10
+global irq11
+global irq12
+global irq13
+global irq14
+global irq15
+
+; IRQ 0: System Timer
+irq0:
+    cli
+    push byte 0
+    push byte 32
+    jmp irq_common_stub
+
+; IRQ 1: Keyboard
+irq1:
+    cli
+    push byte 0
+    push byte 33
+    jmp irq_common_stub
+
+; IRQ 2: Cascade (never raised)
+irq2:
+    cli
+    push byte 0
+    push byte 34
+    jmp irq_common_stub
+
+; IRQ 3: COM2
+irq3:
+    cli
+    push byte 0
+    push byte 35
+    jmp irq_common_stub
+
+; IRQ 4: COM1
+irq4:
+    cli
+    push byte 0
+    push byte 36
+    jmp irq_common_stub
+
+; IRQ 5: LPT2
+irq5:
+    cli
+    push byte 0
+    push byte 37
+    jmp irq_common_stub
+
+; IRQ 6: Floppy Disk
+irq6:
+    cli
+    push byte 0
+    push byte 38
+    jmp irq_common_stub
+
+; IRQ 7: LPT1
+irq7:
+    cli
+    push byte 0
+    push byte 39
+    jmp irq_common_stub
+
+; IRQ 8: CMOS Real-time Clock
+irq8:
+    cli
+    push byte 0
+    push byte 40
+    jmp irq_common_stub
+
+; IRQ 9: Free for peripherals
+irq9:
+    cli
+    push byte 0
+    push byte 41
+    jmp irq_common_stub
+
+; IRQ 10: Free for peripherals
+irq10:
+    cli
+    push byte 0
+    push byte 42
+    jmp irq_common_stub
+
+; IRQ 11: Free for peripherals
+irq11:
+    cli
+    push byte 0
+    push byte 43
+    jmp irq_common_stub
+
+; IRQ 12: PS/2 Mouse
+irq12:
+    cli
+    push byte 0
+    push byte 44
+    jmp irq_common_stub
+
+; IRQ 13: FPU
+irq13:
+    cli
+    push byte 0
+    push byte 45
+    jmp irq_common_stub
+
+; IRQ 14: Primary ATA Hard Disk
+irq14:
+    cli
+    push byte 0
+    push byte 46
+    jmp irq_common_stub
+
+; IRQ 15: Secondary ATA Hard Disk
+irq15:
+    cli
+    push byte 0
+    push byte 47
+    jmp irq_common_stub

src/kernel/interrupt/isr.c

@@ -0,0 +1,317 @@
+#include "isr.h"
+#include "idt.h"
+
+/* Port I/O functions */
+static inline void outb(u16 port, u8 val)
+{
+  __asm__ volatile("outb %0, %1" : : "a"(val), "Nd"(port));
+}
+
+static inline u8 inb(u16 port)
+{
+  u8 ret;
+  __asm__ volatile("inb %1, %0" : "=a"(ret) : "Nd"(port));
+  return ret;
+}
+
+/* PIC (Programmable Interrupt Controller) constants */
+#define PIC1_COMMAND 0x20
+#define PIC1_DATA 0x21
+#define PIC2_COMMAND 0xA0
+#define PIC2_DATA 0xA1
+#define PIC_EOI 0x20
+
+/* Array to store custom IRQ handlers */
+static irq_handler_t irq_handlers[16] = {0};
+
+/* Can't do this with a loop because we need the address
+ * of the function names */
+void isr_install()
+{
+  set_idt_gate(0, (u32)isr0);
+  set_idt_gate(1, (u32)isr1);
+  set_idt_gate(2, (u32)isr2);
+  set_idt_gate(3, (u32)isr3);
+  set_idt_gate(4, (u32)isr4);
+  set_idt_gate(5, (u32)isr5);
+  set_idt_gate(6, (u32)isr6);
+  set_idt_gate(7, (u32)isr7);
+  set_idt_gate(8, (u32)isr8);
+  set_idt_gate(9, (u32)isr9);
+  set_idt_gate(10, (u32)isr10);
+  set_idt_gate(11, (u32)isr11);
+  set_idt_gate(12, (u32)isr12);
+  set_idt_gate(13, (u32)isr13);
+  set_idt_gate(14, (u32)isr14);
+  set_idt_gate(15, (u32)isr15);
+  set_idt_gate(16, (u32)isr16);
+  set_idt_gate(17, (u32)isr17);
+  set_idt_gate(18, (u32)isr18);
+  set_idt_gate(19, (u32)isr19);
+  set_idt_gate(20, (u32)isr20);
+  set_idt_gate(21, (u32)isr21);
+  set_idt_gate(22, (u32)isr22);
+  set_idt_gate(23, (u32)isr23);
+  set_idt_gate(24, (u32)isr24);
+  set_idt_gate(25, (u32)isr25);
+  set_idt_gate(26, (u32)isr26);
+  set_idt_gate(27, (u32)isr27);
+  set_idt_gate(28, (u32)isr28);
+  set_idt_gate(29, (u32)isr29);
+  set_idt_gate(30, (u32)isr30);
+  set_idt_gate(31, (u32)isr31);
+
+  set_idt(); // Load with ASM
+}
+
+/* Remap the PIC to avoid conflicts with CPU exceptions */
+static void pic_remap(void)
+{
+  // Start initialization
+  outb(PIC1_COMMAND, 0x11);
+  outb(PIC2_COMMAND, 0x11);
+
+  // Set vector offsets (IRQs 0-7 -> interrupts 32-39, IRQs 8-15 -> interrupts 40-47)
+  outb(PIC1_DATA, 0x20);
+  outb(PIC2_DATA, 0x28);
+
+  // Tell master PIC there's a slave PIC at IRQ2
+  outb(PIC1_DATA, 0x04);
+  // Tell slave PIC its cascade identity
+  outb(PIC2_DATA, 0x02);
+
+  // Set to 8086 mode
+  outb(PIC1_DATA, 0x01);
+  outb(PIC2_DATA, 0x01);
+
+  // Mask all interrupts initially
+  outb(PIC1_DATA, 0xFF);
+  outb(PIC2_DATA, 0xFF);
+}
+
+/* Install IRQ handlers */
+void irq_install()
+{
+  // Remap the PIC
+  pic_remap();
+
+  // Install IRQ handlers (32-47)
+  set_idt_gate(32, (u32)irq0);
+  set_idt_gate(33, (u32)irq1);
+  set_idt_gate(34, (u32)irq2);
+  set_idt_gate(35, (u32)irq3);
+  set_idt_gate(36, (u32)irq4);
+  set_idt_gate(37, (u32)irq5);
+  set_idt_gate(38, (u32)irq6);
+  set_idt_gate(39, (u32)irq7);
+  set_idt_gate(40, (u32)irq8);
+  set_idt_gate(41, (u32)irq9);
+  set_idt_gate(42, (u32)irq10);
+  set_idt_gate(43, (u32)irq11);
+  set_idt_gate(44, (u32)irq12);
+  set_idt_gate(45, (u32)irq13);
+  set_idt_gate(46, (u32)irq14);
+  set_idt_gate(47, (u32)irq15);
+
+  set_idt(); // Reload IDT
+}
+
+/* To print the message which defines every exception */
+char *exception_messages[] = {
+    "Division By Zero",
+    "Debug",
+    "Non Maskable Interrupt",
+    "Breakpoint",
+    "Into Detected Overflow",
+    "Out of Bounds",
+    "Invalid Opcode",
+    "No Coprocessor",
+
+    "Double Fault",
+    "Coprocessor Segment Overrun",
+    "Bad TSS",
+    "Segment Not Present",
+    "Stack Fault",
+    "General Protection Fault",
+    "Page Fault",
+    "Unknown Interrupt",
+
+    "Coprocessor Fault",
+    "Alignment Check",
+    "Machine Check",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved"};
+
+void isr_handler(registers_t *r)
+{
+  // Write exception to VGA memory
+  char *vidmem = (char *)0xb8000;
+  const char *msg = "EXCEPTION: ";
+  int i = 0;
+
+  // Clear first line
+  for (i = 0; i < 80 * 2; i++)
+  {
+    vidmem[i] = 0;
+  }
+
+  // Write message
+  i = 0;
+  while (msg[i])
+  {
+    vidmem[i * 2] = msg[i];
+    vidmem[i * 2 + 1] = 0x4F; // White on red
+    i++;
+  }
+
+  // Write exception number
+  vidmem[i * 2] = '0' + (r->int_no / 10);
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+  vidmem[i * 2] = '0' + (r->int_no % 10);
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+
+  // Write error code
+  vidmem[i * 2] = ' ';
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+  vidmem[i * 2] = 'E';
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+  vidmem[i * 2] = 'R';
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+  vidmem[i * 2] = 'R';
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+  vidmem[i * 2] = ':';
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+
+  // Write error code in hex
+  u32 err = r->err_code;
+  for (int j = 7; j >= 0; j--)
+  {
+    u8 nibble = (err >> (j * 4)) & 0xF;
+    vidmem[i * 2] = nibble < 10 ? '0' + nibble : 'A' + (nibble - 10);
+    vidmem[i * 2 + 1] = 0x4F;
+    i++;
+  }
+
+  // Write EIP
+  i++;
+  vidmem[i * 2] = 'E';
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+  vidmem[i * 2] = 'I';
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+  vidmem[i * 2] = 'P';
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+  vidmem[i * 2] = ':';
+  vidmem[i * 2 + 1] = 0x4F;
+  i++;
+
+  // Write EIP in hex
+  u32 eip = r->eip;
+  for (int j = 7; j >= 0; j--)
+  {
+    u8 nibble = (eip >> (j * 4)) & 0xF;
+    vidmem[i * 2] = nibble < 10 ? '0' + nibble : 'A' + (nibble - 10);
+    vidmem[i * 2 + 1] = 0x4F;
+    i++;
+  }
+
+  // Halt
+  __asm__ volatile("cli; hlt");
+  while (1)
+    ;
+}
+
+/* IRQ handler */
+void irq_handler(registers_t *r)
+{
+  // Calculate IRQ number (interrupts 32-47 map to IRQ 0-15)
+  u8 irq_no = r->int_no - 32;
+
+  // Handle spurious IRQ7 (from master PIC)
+  if (irq_no == 7)
+  {
+    // Read In-Service Register (ISR)
+    outb(PIC1_COMMAND, 0x0B);
+    u8 isr = inb(PIC1_COMMAND);
+    if (!(isr & 0x80))
+    {
+      // Spurious interrupt, don't send EOI
+      return;
+    }
+  }
+
+  // Handle spurious IRQ15 (from slave PIC)
+  if (irq_no == 15)
+  {
+    // Read In-Service Register (ISR) of slave PIC
+    outb(PIC2_COMMAND, 0x0B);
+    u8 isr = inb(PIC2_COMMAND);
+    if (!(isr & 0x80))
+    {
+      // Spurious interrupt from slave, send EOI to master only
+      outb(PIC1_COMMAND, PIC_EOI);
+      return;
+    }
+  }
+
+  // Call custom handler if registered
+  if (irq_handlers[irq_no] != 0)
+  {
+    irq_handlers[irq_no](r);
+  }
+
+  // Send EOI to PIC
+  if (r->int_no >= 40)
+  {
+    // IRQ came from slave PIC, send EOI to both
+    outb(PIC2_COMMAND, PIC_EOI);
+  }
+  outb(PIC1_COMMAND, PIC_EOI);
+}
+
+/* Register a custom IRQ handler */
+void irq_register_handler(u8 irq, irq_handler_t handler)
+{
+  if (irq < 16)
+  {
+    irq_handlers[irq] = handler;
+
+    // Unmask the IRQ on the PIC
+    u16 port;
+    u8 value;
+
+    if (irq < 8)
+    {
+      port = PIC1_DATA;
+    }
+    else
+    {
+      port = PIC2_DATA;
+      irq -= 8;
+    }
+
+    value = inb(port) & ~(1 << irq);
+    outb(port, value);
+  }
+}

src/kernel/interrupt/isr.h

@@ -0,0 +1,78 @@
+#ifndef ISR_H
+#define ISR_H
+
+#include "types.h"
+
+/* ISRs reserved for CPU exceptions */
+extern void isr0();
+extern void isr1();
+extern void isr2();
+extern void isr3();
+extern void isr4();
+extern void isr5();
+extern void isr6();
+extern void isr7();
+extern void isr8();
+extern void isr9();
+extern void isr10();
+extern void isr11();
+extern void isr12();
+extern void isr13();
+extern void isr14();
+extern void isr15();
+extern void isr16();
+extern void isr17();
+extern void isr18();
+extern void isr19();
+extern void isr20();
+extern void isr21();
+extern void isr22();
+extern void isr23();
+extern void isr24();
+extern void isr25();
+extern void isr26();
+extern void isr27();
+extern void isr28();
+extern void isr29();
+extern void isr30();
+extern void isr31();
+
+/* IRQ handlers */
+extern void irq0();
+extern void irq1();
+extern void irq2();
+extern void irq3();
+extern void irq4();
+extern void irq5();
+extern void irq6();
+extern void irq7();
+extern void irq8();
+extern void irq9();
+extern void irq10();
+extern void irq11();
+extern void irq12();
+extern void irq13();
+extern void irq14();
+extern void irq15();
+
+/* Struct which aggregates many registers */
+typedef struct
+{
+  u32 ds;                                     /* Data segment selector */
+  u32 edi, esi, ebp, esp, ebx, edx, ecx, eax; /* Pushed by pusha. */
+  u32 int_no, err_code;                       /* Interrupt number and error code (if applicable) */
+  u32 eip, cs, eflags, useresp, ss;           /* Pushed by the processor automatically */
+} registers_t;
+
+/* Function pointer type for IRQ handlers */
+typedef void (*irq_handler_t)(registers_t *);
+
+void isr_install();
+void isr_handler(registers_t *r);
+void irq_install();
+void irq_handler(registers_t *r);
+
+/* Register a custom IRQ handler */
+void irq_register_handler(u8 irq, irq_handler_t handler);
+
+#endif

src/kernel/interrupt/types.h

@@ -0,0 +1,16 @@
+#ifndef TYPES_H
+#define TYPES_H
+
+/* Instead of using 'chars' to allocate non-character bytes,
+ * we will use these new type with no semantic meaning */
+typedef unsigned int u32;
+typedef int s32;
+typedef unsigned short u16;
+typedef short s16;
+typedef unsigned char u8;
+typedef char s8;
+
+#define low_16(address) (u16)((address) & 0xFFFF)
+#define high_16(address) (u16)(((address) >> 16) & 0xFFFF)
+
+#endif

src/kernel/kernel.c

@@ -1,7 +1,9 @@
 #include <string.h>
 #include <stdint.h>
+#include <stdio.h>
 #include <duktape.h>
 #include "embedded_js.h"
+#include "interrupt/isr.h"
 
 #define WHITE_TXT 0x0F
 
@@ -56,6 +58,35 @@ duk_ret_t native_ptout(duk_context *ctx)
   return 0;
 }
 
+duk_ret_t native_byte_in(duk_context *ctx)
+{
+  // Get the port (first argument)
+  uint16_t port = (uint16_t)duk_to_uint32(ctx, 0);
+
+  uint8_t result;
+  __asm__ volatile("inb %1, %0"
+                   : "=a"(result)
+                   : "Nd"(port));
+
+  duk_push_uint(ctx, (duk_uint_t)result);
+  return 1;
+}
+
+duk_ret_t native_byte_out(duk_context *ctx)
+{
+  // Get the port (first argument)
+  uint16_t port = (uint16_t)duk_to_uint32(ctx, 0);
+
+  // Get the value to write (second argument)
+  uint8_t value = (uint8_t)duk_to_uint32(ctx, 1);
+
+  __asm__ volatile("outb %0, %1"
+                   :
+                   : "a"(value), "Nd"(port));
+
+  return 0;
+}
+
 duk_ret_t native_dword_in(duk_context *ctx)
 {
   // Get the port (first argument)
@@ -85,10 +116,90 @@ duk_ret_t native_dword_out(duk_context *ctx)
   return 0;
 }
 
+// Global context for IRQ handlers
+duk_context *global_ctx = NULL;
+
+// JavaScript IRQ wrapper
+void js_irq_callback(registers_t *r)
+{
+  if (global_ctx == NULL)
+    return;
+
+  // Get IRQ number
+  u8 irq_no = r->int_no - 32;
+
+  // Build the key for this IRQ handler manually (avoid snprintf in interrupt)
+  char key[32] = "irq_handler_";
+  int key_len = 12;
+  if (irq_no >= 10)
+  {
+    key[key_len++] = '0' + (irq_no / 10);
+    key[key_len++] = '0' + (irq_no % 10);
+  }
+  else
+  {
+    key[key_len++] = '0' + irq_no;
+  }
+  key[key_len] = '\0';
+
+  // Call the JavaScript handler
+  duk_push_global_stash(global_ctx);
+
+  if (duk_get_prop_string(global_ctx, -1, key))
+  {
+    // Function found, call it with IRQ number
+    duk_push_uint(global_ctx, irq_no);
+
+    // Try protected call with error handler
+    duk_int_t rc = duk_pcall(global_ctx, 1);
+    duk_pop(global_ctx); // Pop result or error
+  }
+  else
+  {
+    duk_pop(global_ctx); // Pop undefined value
+  }
+
+  duk_pop(global_ctx); // Pop stash
+}
+
+// Native function to register IRQ from JavaScript
+duk_ret_t native_irq_register(duk_context *ctx)
+{
+  // Get the IRQ number
+  u8 irq = (u8)duk_to_uint32(ctx, 0);
+
+  // Get the handler function
+  if (!duk_is_function(ctx, 1))
+  {
+    duk_push_boolean(ctx, 0);
+    return 1;
+  }
+
+  // Store function in global stash
+  char key[32];
+  snprintf(key, sizeof(key), "irq_handler_%d", irq);
+
+  duk_push_global_stash(ctx);
+  duk_dup(ctx, 1); // Duplicate the function
+  duk_put_prop_string(ctx, -2, key);
+  duk_pop(ctx); // Pop stash
+
+  // Register the C wrapper
+  irq_register_handler(irq, js_irq_callback);
+
+  duk_push_boolean(ctx, 1);
+  return 1;
+}
+
 void kmain()
 {
+  // Initialize IDT and ISRs
+  isr_install();
+  irq_install();
+
   // Initialize Duktape heap
   ctx = duk_create_heap_default();
+  global_ctx = ctx;
 
   // Register native memory write function
   duk_push_c_function(ctx, native_addrw, 2);
@@ -102,6 +213,14 @@ void kmain()
   duk_push_c_function(ctx, native_ptout, 2);
   duk_put_global_string(ctx, "$ptout");
 
+  // Register native byte in function
+  duk_push_c_function(ctx, native_byte_in, 1);
+  duk_put_global_string(ctx, "$bytein");
+
+  // Register native byte out function
+  duk_push_c_function(ctx, native_byte_out, 2);
+  duk_put_global_string(ctx, "$byteout");
+
   // Register native dword in function
   duk_push_c_function(ctx, native_dword_in, 1);
   duk_put_global_string(ctx, "$dwordin");
@@ -110,6 +229,13 @@ void kmain()
   duk_push_c_function(ctx, native_dword_out, 2);
   duk_put_global_string(ctx, "$dwordout");
 
+  // Register native IRQ registration function
+  duk_push_c_function(ctx, native_irq_register, 2);
+  duk_put_global_string(ctx, "$irqregister");
+
+  // Enable interrupts before JavaScript execution
+  __asm__ volatile("sti");
+
   // Execute embedded JavaScript code from build/index.js
   duk_push_string(ctx, embedded_js_code);
   duk_int_t returnCode = duk_peval(ctx);

src/os/src/config/keyboard.ts

@@ -0,0 +1,57 @@
+export const Keycode = {
+  Q: 16,
+  W: 17,
+  E: 18,
+  R: 19,
+  T: 20,
+  Y: 21,
+  U: 22,
+  I: 23,
+  O: 24,
+  P: 25,
+  A: 30,
+  S: 31,
+  D: 32,
+  F: 33,
+  G: 34,
+  H: 35,
+  J: 36,
+  K: 37,
+  L: 38,
+  Z: 44,
+  X: 45,
+  C: 46,
+  V: 47,
+  B: 48,
+  N: 49,
+  M: 50,
+};
+
+export const RKeycode = {
+  16: "Q",
+  17: "W",
+  18: "E",
+  19: "R",
+  20: "T",
+  21: "Y",
+  22: "U",
+  23: "I",
+  24: "O",
+  25: "P",
+  30: "A",
+  31: "S",
+  32: "D",
+  33: "F",
+  34: "G",
+  35: "H",
+  36: "J",
+  37: "K",
+  38: "L",
+  44: "Z",
+  45: "X",
+  46: "C",
+  47: "V",
+  48: "B",
+  49: "N",
+  50: "M",
+};

src/os/src/kernel/drivers/dev/keyboard.ts

@@ -0,0 +1,29 @@
+import { Keycode, RKeycode } from "../../../config/keyboard";
+import { Logger } from "../../../lib/libstd/logger/logger.kmod";
+import { bytein } from "../../../lib/libts/byte";
+import { kmod_cpu_irq_register } from "../../modules/cpu/interrupts";
+import { kmod_terminal_input_handleKeyboardInput } from "../../modules/terminal/input";
+
+export function kdriver_dev_keyboard_handleInterrupt(): void {
+  const scancode = bytein(0x60);
+
+  const key = RKeycode[scancode as keyof typeof RKeycode] as
+    | keyof typeof Keycode
+    | undefined;
+
+  if (key == undefined) return;
+
+  kmod_terminal_input_handleKeyboardInput(key);
+}
+
+export function kdriver_dev_keyboard_init(): void {
+  if (!kmod_cpu_irq_register(1, kdriver_dev_keyboard_handleInterrupt, null)) {
+    Logger.log("[keyboard] Failed to register keyboard interrupt");
+    return;
+  }
+
+  let key = 0;
+  while ((key = bytein(0x64) & 1) == 1) {
+    bytein(0x60);
+  }
+}

src/os/src/kernel/index.ts

@@ -22,6 +22,10 @@ import {
   kmod_graphics_vga_init,
   kmod_graphics_vga_pushLine,
 } from "./modules/graphics/graphics.kmod";
+import {
+  kmod_terminal_input_init,
+  kmod_terminal_input_onKeyboardInput,
+} from "./modules/terminal/input";
 
 export function kmain() {
   kmod_drivers_init();
@@ -33,14 +37,17 @@ export function kmain() {
   kmod_filesystem_init();
   kmod_filesystem_mount("/sys", sysfs_driver);
 
+  Logger.log("[Kernel] Initializing terminal module...");
+  kmod_terminal_input_init();
+
   Logger.log("[Kernel] Initializing PCI devices...");
   kdriver_dev_pci_detectDevices();
 
   Logger.log("[Kernel] Initializing VGA module...");
   kmod_graphics_vga_init();
   kmod_graphics_vga_pushLine("[Kernel] Kernel initialized successfully.");
-  kmod_graphics_vga_pushLine("Current date: " + getDate().toDateString());
+
-  kmod_graphics_vga_pushLine(
+  kmod_terminal_input_onKeyboardInput(function (keycode) {
-    Number(kmod_filesystem_readFile("/sys/pci/0:1:0/vendor")).toString(16)
+    kmod_graphics_vga_pushLine(keycode);
-  );
+  });
 }

src/os/src/kernel/modules/cpu/interrupts.ts

@@ -0,0 +1,43 @@
+import { Logger } from "../../../lib/libstd/logger/logger.kmod";
+import type { KInterrupt, KInterruptHandler } from "../../../types/interrupt";
+
+const kmod_cpu_irq_data: KInterrupt[] = [];
+
+export function kmod_cpu_irq_register(
+  irq: number,
+  handler: KInterruptHandler,
+  data: unknown
+): boolean {
+  if (kmod_cpu_irq_data[irq]) {
+    Logger.log("[IRQ] IRQ " + irq + " is already registered.");
+    return false;
+  }
+
+  if (irq > 15) {
+    Logger.log("[IRQ] IRQ " + irq + " is out of bounds.");
+    return false;
+  }
+
+  kmod_cpu_irq_data[irq] = {
+    handler: handler,
+    data: data,
+  };
+
+  function wrapper(irqNum: number) {
+    const irqData = kmod_cpu_irq_data[irqNum];
+    if (irqData) {
+      irqData.handler(irqNum, irqData.data);
+    }
+  }
+
+  const success = $irqregister(irq, wrapper);
+
+  if (!success) {
+    Logger.log("[IRQ] Failed to register IRQ " + irq + " with hardware.");
+    delete kmod_cpu_irq_data[irq];
+    return false;
+  }
+
+  Logger.log("[IRQ] Successfully registered IRQ " + irq);
+  return true;
+}

src/os/src/kernel/modules/drivers/drivers.kmod.ts

@@ -1,7 +1,12 @@
+import { kdriver_dev_keyboard_init } from "../../drivers/dev/keyboard";
 import { kdriver_dev_pci_init } from "../../drivers/dev/pci";
 import { kdriver_etc_serial_init } from "../../drivers/etc/serial";
 
-const drivers = [kdriver_etc_serial_init, kdriver_dev_pci_init];
+const drivers = [
+  kdriver_etc_serial_init,
+  kdriver_dev_pci_init,
+  kdriver_dev_keyboard_init,
+];
 
 export function kmod_drivers_init(): void {}
 

src/os/src/kernel/modules/terminal/input.ts

@@ -0,0 +1,21 @@
+import type { Keycode } from "../../../config/keyboard";
+
+const kmod_terminal_input_keyboardInputHandlers: Array<
+  (keycode: keyof typeof Keycode) => void
+> = [];
+
+export function kmod_terminal_input_init(): void {}
+
+export function kmod_terminal_input_onKeyboardInput(
+  handler: (keycode: keyof typeof Keycode) => void
+) {
+  kmod_terminal_input_keyboardInputHandlers.push(handler);
+}
+
+export function kmod_terminal_input_handleKeyboardInput(
+  keycode: keyof typeof Keycode
+): void {
+  for (let i = 0; i < kmod_terminal_input_keyboardInputHandlers.length; i++) {
+    kmod_terminal_input_keyboardInputHandlers[i]!(keycode);
+  }
+}

src/os/src/kernel/modules/terminal/terminal.kmod.ts

@@ -0,0 +1 @@
+export * from "./input";

src/os/src/lib/libts/byte.ts

@@ -1,3 +1,11 @@
+export function bytein(port: number): number {
+  return $bytein(port);
+}
+
+export function byteout(port: number, value: number): void {
+  $byteout(port, value);
+}
+
 export function charc(char: string): number {
   return char.charCodeAt(0);
 }

src/os/src/types/c/bindings.d.ts

@@ -1,5 +1,11 @@
 declare function $addrw(address: number, value: number): void;
 declare function $ptin(port: number): number;
 declare function $ptout(port: number, value: number): void;
+declare function $bytein(port: number): number;
+declare function $byteout(port: number, value: number): void;
 declare function $dwordin(port: number): number;
 declare function $dwordout(port: number, value: number): void;
+declare const $irqregister: (
+  irq: number,
+  handler: (irqNum: number) => void
+) => boolean;

src/os/src/types/interrupt.ts

@@ -0,0 +1,9 @@
+export type KInterruptHandler = (
+  interruptNumber: number,
+  data?: unknown
+) => void;
+
+export type KInterrupt = {
+  handler: KInterruptHandler;
+  data: unknown;
+};