New directory structure

src/kernel/arch/i386/boot.s

@@ -0,0 +1,44 @@
+/*
+ * Multiboot 
+ */
+.set ALIGN,    1<<0             /* align loaded modules on page boundaries */
+.set MEMINFO,  1<<1             /* provide memory map */
+.set FLAGS,    ALIGN | MEMINFO  /* this is the Multiboot 'flag' field */
+.set MAGIC,    0x1BADB002       /* 'magic number' lets bootloader find the header */
+.set CHECKSUM, -(MAGIC + FLAGS) /* checksum of above, to prove we are multiboot */
+
+.section .multiboot
+.align 4
+.long MAGIC
+.long FLAGS
+.long CHECKSUM
+ 
+
+.section .bss
+.align 16
+stack_bottom:
+.skip 16384 # 16 KiB
+stack_top:
+ 
+
+.section .text
+.global _start
+.type _start, @function
+_start:
+
+ 
+
+	mov $stack_top, %esp
+ 
+
+
+	call _init
+	call kernel_main
+ 
+
+	cli
+1:	hlt
+	jmp 1b
+ 
+
+.size _start, . - _start

src/kernel/arch/i386/crti.s

@@ -0,0 +1,14 @@
+.section .init
+.global _init
+.type _init, @function
+_init:
+	push %ebp
+	movl %esp, %ebp
+	/* gcc will nicely put the contents of crtbegin.o's .init section here. */
+
+.section .fini
+.global _fini
+.type _fini, @function
+_fini:
+	push %ebp
+	movl %esp, %ebp

src/kernel/arch/i386/crtn.s

@@ -0,0 +1,7 @@
+.section .init
+	popl %ebp
+	ret
+
+.section .fini
+	popl %ebp
+	ret

src/kernel/arch/i386/linker.ld

@@ -0,0 +1,43 @@
+/* The bootloader will look at this image and start execution at the symbol
+   designated as the entry point. */
+ENTRY(_start)
+ 
+/* Tell where the various sections of the object files will be put in the final
+   kernel image. */
+SECTIONS
+{
+	/* Begin putting sections at 1 MiB, a conventional place for kernels to be
+	   loaded at by the bootloader. */
+	. = 1M;
+ 
+	/* First put the multiboot header, as it is required to be put very early
+	   early in the image or the bootloader won't recognize the file format.
+	   Next we'll put the .text section. */
+	.text BLOCK(4K) : ALIGN(4K)
+	{
+		*(.multiboot)
+		*(.text)
+	}
+ 
+	/* Read-only data. */
+	.rodata BLOCK(4K) : ALIGN(4K)
+	{
+		*(.rodata)
+	}
+ 
+	/* Read-write data (initialized) */
+	.data BLOCK(4K) : ALIGN(4K)
+	{
+		*(.data)
+	}
+ 
+	/* Read-write data (uninitialized) and stack */
+	.bss BLOCK(4K) : ALIGN(4K)
+	{
+		*(COMMON)
+		*(.bss)
+	}
+ 
+	/* The compiler may produce other sections, by default it will put them in
+	   a segment with the same name. Simply add stuff here as needed. */
+}

src/kernel/arch/i386/tty/kterm.c

@@ -0,0 +1,91 @@
+#include "kterm.h"
+static const size_t VGA_WIDTH = 80;
+static const size_t VGA_HEIGHT = 25;
+
+size_t kterm_row;
+size_t kterm_column;
+uint8_t kterm_color;
+uint16_t* kterm_buffer;
+
+
+static inline uint8_t vga_entry_color( enum vga_color fg, enum vga_color bg) {
+    return fg | bg << 4;
+}
+
+static inline uint16_t vga_entry (unsigned char uc, uint8_t color) {
+    return (uint16_t) uc | (uint16_t) color << 8;
+}
+
+void kterm_init () { 
+    kterm_row = 0;
+    kterm_column = 0;
+    kterm_color = vga_entry_color ( VGA_COLOR_LIGHT_GREY , VGA_COLOR_BLACK);
+    kterm_buffer = (uint16_t*) 0xB8000;
+    for (size_t y = 0; y < VGA_HEIGHT; y++ ){
+        for( size_t x = 0; x < VGA_WIDTH; x++){
+            const size_t index = y * VGA_WIDTH + x;
+            kterm_buffer[index] = vga_entry(' ', kterm_color);
+
+        }
+    }
+}
+
+
+void kterm_resetcolor(){
+     kterm_color = vga_entry_color ( VGA_COLOR_LIGHT_GREY , VGA_COLOR_BLACK);
+}
+
+void kterm_setcolor(uint8_t color){
+    kterm_color = color;
+}
+
+void kterm_putat (char c, uint8_t color, size_t x, size_t y ) {
+    const size_t index = y * VGA_WIDTH + x;
+
+    kterm_buffer[index] = vga_entry(c, color);
+
+}
+
+
+/**
+ *  With the help from:
+ * https://whiteheadsoftware.dev/operating-systems-development-for-dummies/
+ **/ 
+void kterm_scrollup(){
+    size_t i ;
+    for(i=0; i < (VGA_WIDTH * VGA_HEIGHT - VGA_WIDTH); i++)
+        kterm_buffer[i] = kterm_buffer[i+VGA_WIDTH];
+
+    for( i=0; i< VGA_WIDTH; i++)
+        kterm_buffer[(VGA_HEIGHT -1) * VGA_WIDTH + i ] = vga_entry(' ', kterm_color); 
+
+}
+
+void kterm_put (char c) {
+ 
+    if(++kterm_column == VGA_WIDTH || c == '\n' ) {
+        kterm_column = 0;
+        if(kterm_row == VGA_HEIGHT-1) {       
+            kterm_scrollup();
+        } else {
+            kterm_row ++;
+        }
+            
+    }
+    
+    if(c == '\n') return;
+    kterm_putat ( c, kterm_color, kterm_column, kterm_row);
+    
+
+}
+
+void kterm_write(const char* data, size_t size) {
+    for(size_t i = 0; i < size; i++){
+        kterm_put(data[i]);
+    }
+}   
+
+void kterm_writestring(const char* data ){
+    AS_KERNEL();
+    kterm_write(data, strlen(data));
+}

src/kernel/arch/i386/tty/kterm.h

@@ -0,0 +1,22 @@
+#pragma once 
+#include <stdint.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include "../vga/colors.h"
+
+void kterm_init();
+
+void kterm_resetcolor();
+void kterm_setcolor(uint8_t);
+
+void kterm_putat(char, uint8_t, size_t, size_t);
+void kterm_put(char);
+void kterm_write(const char*, size_t);
+void kterm_writestring(const char*);
+void kterm_scrollup();
+
+#define KernelTag "[Kernel]: "
+#define AS_KERNEL() (  kterm_setcolor(VGA_COLOR_LIGHT_BLUE),\
+                       kterm_write(KernelTag, 10 ), \
+                       kterm_resetcolor())

src/kernel/arch/i386/vga/colors.h

@@ -0,0 +1,19 @@
+#pragma once 
+enum vga_color {
+	VGA_COLOR_BLACK = 0,
+	VGA_COLOR_BLUE = 1,
+	VGA_COLOR_GREEN = 2,
+	VGA_COLOR_CYAN = 3,
+	VGA_COLOR_RED = 4,
+	VGA_COLOR_MAGENTA = 5,
+	VGA_COLOR_BROWN = 6,
+	VGA_COLOR_LIGHT_GREY = 7,
+	VGA_COLOR_DARK_GREY = 8,
+	VGA_COLOR_LIGHT_BLUE = 9,
+	VGA_COLOR_LIGHT_GREEN = 10,
+	VGA_COLOR_LIGHT_CYAN = 11,
+	VGA_COLOR_LIGHT_RED = 12,
+	VGA_COLOR_LIGHT_MAGENTA = 13,
+	VGA_COLOR_LIGHT_BROWN = 14,
+	VGA_COLOR_WHITE = 15,
+};

src/kernel/kernel.c

@@ -0,0 +1,27 @@
+#include "kernel.h"
+/**
+ *      simple delay function 
+ **/
+void delay(int t){
+    volatile int i,j;
+    for(i=0;i<t;i++)
+        for(j=0;j<25000;j++)
+            asm("NOP");
+}
+
+void kernel_main (void) {
+    /** initialize terminal interface */ 
+    kterm_init();
+
+    /** Wrtite stuff to the screen to test the terminal**/ 
+    kterm_writestring("Hello world!\n");
+    kterm_writestring("We got newline support!\n");
+
+    for(;;){
+        delay(500);
+        kterm_writestring("We have implemented terminal scrolling!\n");
+    }
+   
+   
+}   
+

src/kernel/kernel.h

@@ -0,0 +1,3 @@
+#pragma once 
+#include "../libc/include/string.h"
+#include "arch/i386/tty/kterm.h"