fixing the keyboard and bootloader so that its 2 stage again

bootloader/boot.asm

@@ -1,67 +1,230 @@
+; ==============================================================================
+; boot.asm - First Stage Bootloader (CHS Based)
+; ==============================================================================
+
 [BITS 16]
 [ORG 0x7C00]
 
 start:
-    cli
+    cli                         ; Disable interrupts
+
+    mov [bootdev], dl           ; Save boot device number (from BIOS in DL)
+
+    ; Setup stack safely below EBDA area (choose 0x0000:0x7A00)
+    xor ax, ax                  ; AX = 0
+    mov ss, ax                  ; Stack segment = 0x0000
+    mov sp, 0x7A00              ; Stack offset = 0x7A00
+
+    ; Initialize DS, ES for zero-based segments
     xor ax, ax
     mov ds, ax
     mov es, ax
-    mov ss, ax
-    mov sp, 0x7C00
 
+    ; Load second-stage bootloader (boot1.asm) to 0x7E00
+    mov si, 0x7E00              ; Destination offset (ES already zero, so physical 0x7E00)
+    mov al, 1                   ; Number of sectors to read (adjust if needed)
+    mov cl, 1                   ; Starting sector (CHS - sector number, 1-based)
+    call read_chs
+    jc disk_error               ; Jump if carry set (read error)
+
+    ; Load kernel to 0x100000 (1 MB)
+    mov si, 0x0000              ; Destination offset
+    mov ax, 0x1000              ; ES = 0x1000 (0x1000:0x0000 = 1 MB)
+    mov es, ax
+    xor bx, bx
+    mov al, 16                  ; Number of sectors for kernel (example)
+    mov cl, 2                   ; Starting sector (adjust as per your disk layout)
+    call read_chs
+    jc disk_error
+
+    ; Memory Validation: Verify checksum of second stage bootloader
+    mov si, 0x7E00             ; Start of second stage
+    mov cx, 512                ; Size in bytes (adjust if more sectors loaded)
+    call verify_checksum
+    jc disk_error              ; Jump if checksum fails
+
+    ; Enable A20 line
     call enable_a20
+    jc a20_error                ; Jump if A20 enable fails
+
+    ; Setup Global Descriptor Table
     call setup_gdt
+
+    ; Switch to protected mode and jump to second stage at 0x08:0x7E00
     call switch_to_pm
 
-; ----------------------
+disk_error:
-; A20 Gate Enable (Fast method)
+    mov si, disk_error_msg
+    call print_string_16
+    jmp halt
+
+a20_error:
+    mov si, a20_error_msg
+    call print_string_16
+    jmp halt
+
+; ----------------------------------------------------------------
+; Verify Checksum Routine
+; Uses SI = start address, CX = byte count
+; Simple XOR checksum over bytes, expects result 0
+
+verify_checksum:
+    push ax
+    push bx
+    push di
+    mov di, si
+    xor al, al
+    xor bx, bx
+
+.verify_loop:
+    lodsb
+    xor bl, al
+    loop .verify_loop
+
+    test bl, bl
+    jz .checksum_ok
+    stc                    ; Set carry on checksum error
+    jmp .done
+
+.checksum_ok:
+    clc                    ; Clear carry on success
+
+.done:
+    pop di
+    pop bx
+    pop ax
+    ret
+
+; ----------------------------------------------------------------
+; CHS Disk Read Routine
+; AL = number of sectors
+; CL = starting sector (1-based)
+; SI = destination offset (Segment:ES already set)
+read_chs:
+    pusha
+    push dx
+    mov cx, 5
+.retry:
+    mov ah, 0x02             ; BIOS read sector
+    mov dl, [bootdev]        ; Drive number
+    int 0x13
+
+    jc .error                ; Carry flag set = error
+    pop dx
+    popa
+    ret
+
+.error:
+    dec cx
+    jz disk_error
+    xor ah, ah
+    int 0x13
+    jmp .retry
+
+; ----------------------------------------------------------------
 enable_a20:
+    ; Fast A20 gate method
     in al, 0x92
     or al, 0x02
     out 0x92, al
+    ; Fallback method (keyboard controller)
+    jc .fallbackenable_a20:
+    ; Fast A20 method
+    in al, 0x92
+    or al, 0x02
+    and al, 0xFE  ; Clear bit 0 to avoid fast A20 issues on some systems
+    out 0x92, al
+    ; Verify A20
+    call check_a20
+    jnc .done
+    ; Fallback method
+    mov al, 0xAD
+    out 0x64, al
+    ; ... (rest of keyboard controller code)
+.done:
     ret
 
-; ----------------------
+check_a20:
-; Set up a minimal GDT
+    in al, 0x64              ; Read keyboard controller status
+    test al, 0x02            ; Check if input buffer is full
+    jnz check_a20            ; Wait until empty
+
+    mov al, 0xD0             ; Command: read output port
+    out 0x64, al
+
+.wait_output:
+    in al, 0x60              ; Read output port value
+    test al, 0x02            ; Check A20 gate bit (bit 1)
+    jnz .a20_enabled         ; If set, A20 enabled
+
+    xor al, al               ; Clear carry to indicate failure
+    stc                      ; Set carry for failure, jc will jump
+
+    ret
+
+.a20_enabled:
+    clc                      ; Clear carry flag to indicate success
+    ret
+
+.fallback:
+    mov al, 0xAD
+    out 0x64, al
+    mov al, 0xD0
+    out 0x64, al
+    in al, 0x60
+    or al, 0x02
+    mov al, 0xD1
+    out 0x64, al
+    mov al, 0xAE
+    out 0x64, al
+    ret
+
+; ----------------------------------------------------------------
 gdt_start:
-    dq 0x0000000000000000          ; null descriptor
+    dq 0x0000000000000000         ; Null descriptor
-    dq 0x00CF9A000000FFFF          ; code segment descriptor
+    dq 0x00CF9A000000FFFF         ; 32-bit code segment (selector 0x08)
-    dq 0x00CF92000000FFFF          ; data segment descriptor
+    dq 0x00CF92000000FFFF         ; 32-bit data segment (selector 0x10)
+    dq 0x00009A000000FFFF         ; 16-bit code segment for real mode (selector 0x18)
 
 gdt_descriptor:
-    dw gdt_end - gdt_start - 1     ; size of GDT
+    dw gdt_end - gdt_start - 1
-    dd gdt_start                   ; address of GDT
+    dd gdt_start
-
 gdt_end:
 
 setup_gdt:
     lgdt [gdt_descriptor]
     ret
 
-; ----------------------
+; ----------------------------------------------------------------
-; Switch to Protected Mode
 switch_to_pm:
     cli
     mov eax, cr0
     or eax, 1
     mov cr0, eax
-    jmp 0x08:protected_mode_entry
+    jmp 0x08:0x7E00
-; ----------------------
-; 32-bit Protected Mode Entry Point
-[BITS 32]
-protected_mode_entry:
-    mov ax, 0x10       ; data segment selector
-    mov ds, ax
-    mov es, ax
-    mov fs, ax
-    mov gs, ax
-    mov ss, ax
-    mov esp, 0x90000
 
-    ; Kernel is assumed to be loaded at 0x100000
+; ----------------------------------------------------------------
-    jmp 0x08:0x100000
+print_string_16:
+.loop:
+    lodsb
+    or al, al
+    jz .done
+    mov ah, 0x0E
+    int 0x10
+    jmp .loop
+.done:
+    ret
+
+disk_error_msg db "Disk error!", 0
+a20_error_msg db "A20 error!", 0
+
+halt:
+    cli
+    hlt
+
+bootdev db 0
+sectors_per_track dw 63
+heads_per_cylinder dw 255
 
-; ----------------------
-; Boot signature
 times 510 - ($ - $$) db 0
 dw 0xAA55

bootloader/boot1.asm

@@ -0,0 +1,182 @@
+; ==============================================================================
+; boot1.asm - Second Stage Bootloader (Fixed Real Mode Transition)
+; ==============================================================================
+
+[BITS 32]
+global _start
+extern kmain
+
+_start:
+    ; Set up segments
+    mov ax, 0x10
+    mov ds, ax
+    mov es, ax
+    mov fs, ax
+    mov gs, ax
+    mov ss, ax
+
+    ; Stack (must be identity-mapped)
+    mov esp, 0x90000
+
+    ; CPU Feature Detection: check CPUID support
+    pushfd                      ; Save flags
+    pop eax
+    mov ecx, eax
+    xor eax, 1 << 21            ; Flip ID bit
+    push eax
+    popfd
+    pushfd
+    pop eax
+    xor eax, ecx
+    jz .no_cpuid                ; CPUID unsupported if no change
+
+    ; CPUID supported, verify features
+    mov eax, 1
+    cpuid
+    ; Check for paging support (bit 31 of edx)
+    test edx, 1 << 31
+    jz .no_paging_support
+
+    ; Additional CPU feature checks could be added here
+
+    jmp .cpuid_check_done
+
+.no_cpuid:
+    mov si, no_cpuid_msg
+    call print_string_16
+    jmp halt
+
+.no_paging_support:
+    mov si, no_paging_msg
+    call print_string_16
+    jmp halt
+
+.cpuid_check_done:
+
+    ; Temporarily switch back to real mode
+    cli
+    mov eax, cr0
+    and eax, 0x7FFFFFFE        ; Clear PE & PG bits
+    mov cr0, eax
+    jmp 0x18:real_mode_entry
+
+; ----------------------------------------------------------------
+[BITS 16]
+real_mode_entry:
+    ; Real mode for BIOS access (E820, VESA)
+    xor ax, ax
+    mov es, ax
+
+    ; VESA call
+    mov di, VbeControllerInfo
+    mov ax, 0x4F00
+    int 0x10
+    jc vesa_error
+
+    ; E820 memory map
+    xor ebx, ebx
+    mov edx, 0x534D4150
+    mov di, MemoryMapBuffer
+    mov [MemoryMapEntries], dword 0
+
+.e820_loop:
+    mov eax, 0xE820
+    mov ecx, 24
+    int 0x15
+    jc e820_error
+    add di, 24
+    inc dword [MemoryMapEntries]
+    test ebx, ebx
+    jnz .e820_loop
+    jmp .e820_done
+
+e820_error:
+    mov si, e820_error_msg
+    call print_string_16
+    jmp halt
+
+vesa_error:
+    mov si, vesa_error_msg
+    call print_string_16
+
+    ; Fallback: set VGA text mode 3 and continue
+    mov ah, 0x00           ; BIOS Set Video Mode function
+    mov al, 0x03           ; VGA 80x25 text mode
+    int 0x10
+
+    ; Clear screen
+    mov ah, 0x06           ; Scroll up function
+    mov al, 0              ; Clear entire screen
+    mov bh, 0x07           ; Text attribute (gray on black)
+    mov cx, 0              ; Upper-left corner
+    mov dx, 0x184F         ; Lower-right corner
+    int 0x10
+
+    jmp .e820_done         ; Continue booting without VESA graphics
+
+.e820_done:
+    ; Back to protected mode
+    cli
+    mov eax, cr0
+    or eax, 1
+    mov cr0, eax
+    jmp 0x08:protected_entry
+
+; ----------------------------------------------------------------
+print_string_16:
+.loop:
+    lodsb
+    or al, al
+    jz .done
+    mov ah, 0x0E
+    int 0x10
+    jmp .loop
+.done:
+    ret
+
+e820_error_msg db "E820 Failed!", 0
+vesa_error_msg db "VESA Failed!", 0
+no_cpuid_msg db "No CPUID support detected!", 0
+no_paging_msg db "CPU lacks paging support!", 0
+
+; ----------------------------------------------------------------
+[BITS 32]
+protected_entry:
+    ; Paging setup
+    xor eax, eax
+    mov edi, page_directory
+    mov ecx, 1024
+    rep stosd
+    mov edi, page_table
+    rep stosd
+
+    mov dword [page_directory], page_table | 0x3
+    mov ecx, 1024
+    mov edi, page_table
+    mov eax, 0x00000003
+.fill_pages:
+    mov [edi], eax
+    add eax, 0x1000
+    add edi, 4
+    loop .fill_pages
+
+    mov eax, page_directory
+    mov cr3, eax
+    mov eax, cr0
+    or eax, 0x80000000
+    mov cr0, eax
+
+    jmp kmain
+
+; ----------------------------------------------------------------
+; Data buffers and variables must be appropriately defined in your data section
+MemoryMapBuffer times 128 db 0          ; 128*24 bytes reserved for E820 memory map (adjust size as needed)
+MemoryMapEntries dd 0
+VbeControllerInfo times 512 db 0        ; Buffer for VESA controller info (adjust size as needed)
+
+; Define page directory and page table aligned as needed (in your data section)
+align 4096
+page_directory times 1024 dd 0
+align 4096
+page_table times 1024 dd 0
+

bootloader/linker.ld

@@ -1,10 +1,9 @@
-ENTRY(start)
+ENTRY(kmain)
 
 SECTIONS {
     . = 1M;
 
     .text : {
-        *(.multiboot)
         *(.text*)
     }
 

kernel/keyboard.c

@@ -20,34 +20,40 @@ static const char scancode_map[128] = {
 };
 
 // Interrupt handler for IRQ1
-void keyboard_callback() {
+void keyboard_callback(void) {
-    uint8_t scancode = inb(KEYBOARD_DATA_PORT);
+    uint8_t scancode = inb(0x60);
 
-    // Ignore key releases (scancodes with high bit set)
+    // Only handle key press (ignore key release)
-    if (scancode & 0x80)
+    if (!(scancode & 0x80)) {
-        return;
+        char c = scancode_map[scancode];
-
+        if (c && buffer_index < sizeof(key_buffer) - 1) {
-    char c = scancode_map[scancode];
+            key_buffer[buffer_index++] = c;
-    if (c && buffer_index < sizeof(key_buffer) - 1) {
+            terminal_putchar(c);
-        key_buffer[buffer_index++] = c;
+        }
-        terminal_putchar(c); // Echo to terminal (optional)
     }
+
+    // Send End of Interrupt (EOI) to the PIC
+    outb(0x20, 0x20);
 }
 
+
 void keyboard_init() {
     register_interrupt_handler(33, keyboard_callback); // IRQ1 = int 33 (0x21)
 }
 
 // Blocking read (returns one char)
 char keyboard_get_char() {
-    while (buffer_index == 0);
+    while (buffer_index == 0); // Busy wait
-    char c = key_buffer[0];
 
-    // Shift buffer left
+    char c;
+    __asm__ __volatile__("cli");
+    c = key_buffer[0];
     for (uint8_t i = 1; i < buffer_index; i++) {
         key_buffer[i - 1] = key_buffer[i];
     }
     buffer_index--;
+    __asm__ __volatile__("sti");
 
     return c;
 }
+

kernel/kmain.c

@@ -11,6 +11,7 @@
 #include "kmalloc.h"
 #include "timer.h"
 #include "utils.h"
+#include "keyboard.h"
 
 #define LPT1 0x378
 
@@ -54,6 +55,10 @@ void kmain(void) {
     timer_init(100);  // 100 Hz (10 ms interval)
     serial_write("Timer initialized.\n");
 
+    terminal_write("Initializing keyboard...\n");
+    keyboard_init();
+    serial_write("Keyboard initialized.\n");
+
     terminal_write("Getting memory map...\n");
     memory_map_entry_t mmap[32];
     uint32_t mmap_size = get_memory_map(mmap, 32);

kernel/timer.c

@@ -4,17 +4,20 @@
 #include "terminal.h"
 #include "stdio.h"
 
-static uint32_t tick = 0;
+static volatile uint32_t tick = 0;
 
 void timer_callback(void) {
     tick++;
-    
+
-    // Print every 100 ticks for debugging purposes
     if (tick % 100 == 0) {
-        char tick_msg[50];
+        char buf[16];
-        snprintf(tick_msg, sizeof(tick_msg), "Tick count: %u\n", tick);
+        itoa(tick, buf, 10);
-        terminal_write(tick_msg);
+        terminal_write("Tick count: ");
+        terminal_write(buf);
+        terminal_write("\n");
     }
+
+    outb(0x20, 0x20); // EOI to PIC
 }
 
 void timer_init(uint32_t frequency) {
@@ -29,4 +32,4 @@ void timer_init(uint32_t frequency) {
 
 uint32_t timer_get_ticks(void) {
     return tick;
-}
+}