remove 64 bit for now

makefile

@@ -1,7 +1,7 @@
-CC = x86_64-elf-gcc
+CC = i386-elf-gcc
-LD = x86_64-elf-ld
+LD = i386-elf-ld
 
-CFLAGS = -ffreestanding -m64
+CFLAGS = -ffreestanding -m32
 
 all: .build/nub-os.iso
 
@@ -17,8 +17,8 @@ build-dir:
 	cp .build/kernel.bin .build/iso/boot/
 	grub-mkrescue -o .build/nub-os.iso .build/iso/
 
-.build/kernel.bin: build-dir .build/boot.o .build/kernel.o .build/print.o .build/idt.o .build/keyboard.o .build/exceptions.o .build/interrupts.o
+.build/kernel.bin: build-dir .build/boot.o .build/kernel.o .build/print.o
-	$(LD) -Ttext 0x100000 -o .build/kernel.bin .build/boot.o .build/kernel.o .build/print.o .build/idt.o .build/keyboard.o .build/exceptions.o .build/interrupts.o
+	$(LD) -Ttext 0x100000 -o .build/kernel.bin .build/boot.o .build/kernel.o .build/print.o
 
 .build/kernel.o: build-dir src/kernel.c
 	$(CC) $(CFLAGS) -c -o .build/kernel.o src/kernel.c
@@ -26,17 +26,5 @@ build-dir:
 .build/print.o: build-dir src/print.c
 	$(CC) $(CFLAGS) -c -o .build/print.o src/print.c
 
-.build/idt.o: build-dir src/idt.c
-	$(CC) $(CFLAGS) -c -o .build/idt.o src/idt.c
-
-.build/keyboard.o: build-dir src/keyboard.c
-	$(CC) $(CFLAGS) -c -o .build/keyboard.o src/keyboard.c
-
-.build/exceptions.o: build-dir src/exceptions.c
-	$(CC) $(CFLAGS) -c -o .build/exceptions.o src/exceptions.c
-
-.build/interrupts.o: build-dir src/interrupts.asm
-	nasm -f elf64 -o .build/interrupts.o src/interrupts.asm
-
 .build/boot.o: build-dir src/boot.asm
-	nasm -f elf64 -o .build/boot.o src/boot.asm
+	nasm -f elf32 -o .build/boot.o src/boot.asm

src/boot.asm

@@ -14,14 +14,6 @@ align 4
 header_end:
 
 section .bss
-align 4096
-page_table_l4:
-    resb 4096
-page_table_l3:
-    resb 4096
-page_table_l2:
-    resb 4096
-
 align 16
     resb 16384
 stack_top:
@@ -29,129 +21,11 @@ stack_top:
 extern kernel_main
 
 section .text
-bits 32
 global _start
 _start:
     mov esp, stack_top
-
-    call check_cpuid
-    call check_long_mode
-
-    call setup_page_tables
-    call enable_paging
-
-    lgdt [gdt64.pointer]
-
-    jmp gdt64.kernel_code:long_mode_start
-
-check_cpuid:
-    pushfd
-    pop eax
-    mov ecx, eax
-    xor eax, 1 << 21
-    push eax
-    popfd
-    pushfd
-    pop eax
-    push ecx
-    popfd
-    xor eax, ecx
-    jz .no_cpuid
-    ret
-.no_cpuid:
-    mov al, 'I'
-    jmp error
-
-check_long_mode:
-    mov eax, 0x80000000
-    cpuid
-    cmp eax, 0x80000001
-    jb .no_long_mode
-
-    mov eax, 0x80000001
-    cpuid
-    test edx, 1 << 29
-    jz .no_long_mode
-    ret
-.no_long_mode:
-    mov al, 'L'
-    jmp error
-
-setup_page_tables:
-    mov edi, page_table_l4
-    mov ecx, 4096 * 3 / 4
-    xor eax, eax
-    rep stosd
-
-    mov eax, page_table_l3
-    or eax, 0b11
-    mov [page_table_l4], eax
-
-    mov eax, page_table_l2
-    or eax, 0b11
-    mov [page_table_l3], eax
-
-    mov ecx, 0
-.map_p2_table:
-    mov eax, 0x200000
-    mul ecx
-    or eax, 0b10000011
-    mov [page_table_l2 + ecx * 8], eax
-    inc ecx
-    cmp ecx, 512
-    jne .map_p2_table
-    ret
-
-enable_paging:
-    mov eax, page_table_l4
-    mov cr3, eax
-
-    mov eax, cr4
-    or eax, 1 << 5
-    mov cr4, eax
-
-    mov ecx, 0xC0000080
-    rdmsr
-    or eax, 1 << 8
-    wrmsr
-
-    mov eax, cr0
-    or eax, 1 << 31
-    mov cr0, eax
-    ret
-
-bits 64
-long_mode_start:
-    mov ax, gdt64.kernel_data
-    mov ss, ax
-    mov ds, ax
-    mov es, ax
-    mov fs, ax
-    mov gs, ax
-
-    mov rsp, stack_top
-
     call kernel_main
-
-    cli
 hang:
+    cli
     hlt
     jmp hang
-
-error:
-    mov dword [0xb8000], 0x4f524f45
-    mov dword [0xb8004], 0x4f3a4f52
-    mov dword [0xb8008], 0x4f204f20
-    mov byte  [0xb800a], al
-    hlt
-
-section .rodata
-gdt64:
-    dq 0
-.kernel_code: equ $ - gdt64
-    dq (1<<44) | (1<<47) | (1<<41) | (1<<43) | (1<<53)
-.kernel_data: equ $ - gdt64
-    dq (1<<44) | (1<<47) | (1<<41)
-.pointer:
-    dw $ - gdt64 - 1
-    dq gdt64

src/exceptions.c

@@ -1,30 +0,0 @@
-#include "print.h"
-#include <stdint.h>
-
-void exception_handler(uint64_t* stack)
-{
-    uint64_t interrupt_num = stack[0];
-    uint64_t error_code = stack[1];
-
-    print("EXCEPTION: ");
-    if (interrupt_num == 0)
-    {
-        print("Division by zero");
-    }
-    else if (interrupt_num == 13)
-    {
-        print("General protection fault");
-    }
-    else
-    {
-        print("Unknown exception");
-    }
-    print("\nError code: ");
-    // You'd need to implement number printing here
-    print("\nSystem halted.\n");
-
-    while (1)
-    {
-        __asm__ volatile("hlt");
-    }
-}

src/idt.c

@@ -1,59 +0,0 @@
-#include "idt.h"
-#include "print.h"
-
-#define IDT_ENTRIES 256
-
-struct idt_entry
-{
-    uint16_t offset_low;
-    uint16_t selector;
-    uint8_t ist;
-    uint8_t type_attr;
-    uint16_t offset_mid;
-    uint32_t offset_high;
-    uint32_t zero;
-} __attribute__((packed));
-
-struct idt_ptr
-{
-    uint16_t limit;
-    uint64_t base;
-} __attribute__((packed));
-
-static struct idt_entry idt[IDT_ENTRIES];
-static struct idt_ptr idt_pointer;
-
-extern void isr0(void);
-extern void isr13(void);
-extern void keyboard_handler_asm(void);
-
-static void idt_set_gate(uint8_t num, uint64_t handler, uint16_t sel, uint8_t flags)
-{
-    idt[num].offset_low = handler & 0xFFFF;
-    idt[num].selector = sel;
-    idt[num].ist = 0;
-    idt[num].type_attr = flags;
-    idt[num].offset_mid = (handler >> 16) & 0xFFFF;
-    idt[num].offset_high = (handler >> 32) & 0xFFFFFFFF;
-    idt[num].zero = 0;
-}
-
-void idt_init(void)
-{
-    idt_pointer.limit = (sizeof(struct idt_entry) * IDT_ENTRIES) - 1;
-    idt_pointer.base = (uint64_t)&idt;
-
-    for (int i = 0; i < IDT_ENTRIES; i++)
-    {
-        idt_set_gate(i, 0, 0, 0);
-    }
-
-    idt_set_gate(0, (uint64_t)isr0, 0x08, 0x8E);
-    idt_set_gate(13, (uint64_t)isr13, 0x08, 0x8E);
-    idt_set_gate(33, (uint64_t)keyboard_handler_asm, 0x08, 0x8E);
-
-    __asm__ volatile("lidt %0" : : "m"(idt_pointer));
-
-    print_clr("[success]", FG_GREEN, BG_BLACK);
-    print(" idt initialized\n");
-}

src/idt.h

@@ -1,3 +0,0 @@
-#pragma once
-
-void idt_init(void);

src/interrupts.asm

@@ -1,96 +0,0 @@
-section .text
-
-global isr0
-global isr13
-global keyboard_handler_asm
-
-extern exception_handler
-extern keyboard_handler
-
-isr0:
-    push 0
-    push 0
-    jmp exception_common
-
-isr13:
-    push 13
-    jmp exception_common
-
-exception_common:
-    push rax
-    push rbx
-    push rcx
-    push rdx
-    push rsi
-    push rdi
-    push rbp
-    push r8
-    push r9
-    push r10
-    push r11
-    push r12
-    push r13
-    push r14
-    push r15
-    
-    mov rdi, rsp
-    call exception_handler
-    
-    pop r15
-    pop r14
-    pop r13
-    pop r12
-    pop r11
-    pop r10
-    pop r9
-    pop r8
-    pop rbp
-    pop rdi
-    pop rsi
-    pop rdx
-    pop rcx
-    pop rbx
-    pop rax
-    
-    add rsp, 16
-    iretq
-
-keyboard_handler_asm:
-    push rax
-    push rbx
-    push rcx
-    push rdx
-    push rsi
-    push rdi
-    push rbp
-    push r8
-    push r9
-    push r10
-    push r11
-    push r12
-    push r13
-    push r14
-    push r15
-    
-    call keyboard_handler
-    
-    mov al, 0x20
-    out 0x20, al
-    
-    pop r15
-    pop r14
-    pop r13
-    pop r12
-    pop r11
-    pop r10
-    pop r9
-    pop r8
-    pop rbp
-    pop rdi
-    pop rsi
-    pop rdx
-    pop rcx
-    pop rbx
-    pop rax
-    
-    iretq

src/kernel.c

@@ -1,12 +1,6 @@
-#include "idt.h"
-#include "keyboard.h"
 #include "print.h"
 
 void kernel_main(void)
 {
-    idt_init();
-    keyboard_init();
-
     print("Welcome to nub OS\n");
-    print("> ");
 }

src/keyboard.c

@@ -1,80 +0,0 @@
-#include "print.h"
-#include <stdbool.h>
-#include <stdint.h>
-
-#define KEYBOARD_DATA_PORT 0x60
-#define KEYBOARD_STATUS_PORT 0x64
-
-static char scancode_to_ascii[] = { 0,    0,   '1', '2', '3', '4', '5', '6', '7', '8', '9',  '0', '-', '=',  '\b',
-                                    '\t', 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p',  '[', ']', '\n', 0,
-                                    'a',  's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', '\'', '`', 0,   '\\', 'z',
-                                    'x',  'c', 'v', 'b', 'n', 'm', ',', '.', '/', 0,   '*',  0,   ' ' };
-
-static char input_buffer[256];
-static int buffer_index = 0;
-static bool key_available = false;
-
-static uint8_t inb(uint16_t port)
-{
-    uint8_t result;
-    __asm__ volatile("inb %1, %0" : "=a"(result) : "Nd"(port));
-    return result;
-}
-
-void keyboard_handler(void)
-{
-    uint8_t scancode = inb(KEYBOARD_DATA_PORT);
-
-    if (scancode & 0x80)
-    {
-        return;
-    }
-
-    if (scancode < sizeof(scancode_to_ascii))
-    {
-        char ascii = scancode_to_ascii[scancode];
-        if (ascii)
-        {
-            if (ascii == '\b')
-            {
-                if (buffer_index > 0)
-                {
-                    buffer_index--;
-                    print("\b \b");
-                }
-            }
-            else if (ascii == '\n')
-            {
-                input_buffer[buffer_index] = '\0';
-                print("\n");
-                key_available = true;
-            }
-            else if (buffer_index < 255)
-            {
-                input_buffer[buffer_index++] = ascii;
-                char str[2] = { ascii, '\0' };
-                print(str);
-            }
-        }
-    }
-}
-
-char* keyboard_get_line(void)
-{
-    buffer_index = 0;
-    key_available = false;
-
-    while (!key_available)
-    {
-        __asm__ volatile("hlt");
-    }
-
-    return input_buffer;
-}
-
-void keyboard_init(void)
-{
-    __asm__ volatile("sti");
-    print_clr("[success]", FG_GREEN, BG_BLACK);
-    print(" keyboard initialized\n");
-}

src/keyboard.h

@@ -1,4 +0,0 @@
-#pragma once
-
-void keyboard_init(void);
-char* keyboard_get_line(void);