Project restructure (no new code added)

Moved all header files into include/ and removed their C counterparts -> code inside .h files
Also added a kernel.ld linker file
since we don't have many code files in src/ now, i removed src/kernel/
only real code change is that i moved memcopy() and memset() into string.h from system.h

include/screen.h

@@ -0,0 +1,138 @@
+#ifndef SCREEN_H
+#define SCREEN_H
+
+#include "screen.h"
+#include "stdint.h"
+#include "system.h"
+#include "string.h"
+
+#define VIDMEM 0xb8000
+#define CURSOR_HIGH 14
+#define CURSOR_LOW 15
+#define CTRLREG 0x3d4
+#define DATAREG 0x3d5
+
+// 80x25 VGA Text mode
+#define ROWS 25
+#define COLS 80
+#define CHARS (ROWS*COLS)
+
+uint32_t cursor = 0;
+
+void updateCursor() {
+    // Move visual cursor position
+    outb(0x3d4, 0x0f); // Low byte
+    outb(0x3d5, cursor & 0xff);
+    outb(0x3d4, 0x0e); // High byte
+    outb(0x3d5, cursor >> 8);
+}
+
+void setCursorPos(uint32_t offset) {
+    cursor = offset;
+    updateCursor();
+}
+
+uint32_t getCursorPos() {
+    return cursor;
+}
+
+uint32_t calcOffset(uint8_t col, uint8_t row) {
+    return row * COLS + col;
+}
+
+void scroll() {
+    if (cursor < COLS * ROWS) return;
+
+    for (int i = 1; i < ROWS; i++) {
+        memcopy((char*)(calcOffset(0, i)*2)+VIDMEM, (char*)(calcOffset(0, i-1)*2)+VIDMEM, COLS*2);
+    }
+
+    char* lastRow = (char*)(calcOffset(0, ROWS-1)*2)+VIDMEM;
+    for (int i = 0; i < COLS*2; i += 2) {
+        lastRow[i] = '\0';
+        lastRow[i+1] = 0x0f;
+    }
+
+    cursor = calcOffset(0, ROWS-1);
+}
+
+void putc(char c, uint8_t attr) {
+    if (c == '\n') {
+        uint16_t line = cursor - (cursor % COLS);
+        setCursorPos(line + COLS);
+        scroll();
+        updateCursor();
+        return;
+    } else if (c == '\b') {
+        cursor--;
+        int mem = VIDMEM + cursor * 2;
+        *(char*)(mem) = ' ';
+        *(char*)(mem+1) = attr;
+        updateCursor();
+        return;
+    }
+    
+    int mem = VIDMEM + cursor * 2;
+    *(char*)(mem) = c;
+    *(char*)(mem+1) = attr;
+
+    cursor++;
+
+    scroll();
+    updateCursor();
+}
+
+void print(char* s, uint8_t attr) { 
+    char c = *s;
+    while (c != '\0') {
+        putc(c, attr);
+        c = *(++s);
+    }
+
+    scroll();
+    updateCursor();
+}
+
+void putcAt(char c, uint8_t attr, uint8_t col, uint8_t row) {
+    uint16_t offset = calcOffset(col, row);
+    *(char*)(VIDMEM + offset * 2) = c;
+    *(char*)(VIDMEM + offset * 2 + 1) = attr;
+}
+
+void printAt(char* s, uint8_t attr, uint8_t col, uint8_t row) {
+    uint16_t offset = calcOffset(col, row);
+    
+    char c = *s;
+    while (c != '\0') {
+        *(char*)(VIDMEM + offset * 2) = c;
+        *(char*)(VIDMEM + offset * 2 + 1) = attr;
+        c = *(++s);
+        offset++;
+    }
+}
+
+void clear(uint8_t attr) {
+    for (int i = 0; i < CHARS*2; i += 2) {
+        *(char*)(VIDMEM + i) = ' ';
+        *(char*)(VIDMEM + i + 1) = attr;
+    }
+    cursor = 0;
+
+    updateCursor();
+}
+
+void enableCursor(uint8_t start, uint8_t end) {
+    outb(0x3d4, 0x0a); // Sending cursor start
+    outb(0x3d5, (inb(0x3d5) & 0xc0) | start);
+
+    outb(0x3d4, 0x0b); // Sending cursor end
+    outb(0x3d5, (inb(0x3d5) & 0xe0) | end);
+}
+
+void disableCursor() {
+    outb(0x3d4, 0x0a);
+    outb(0x3d4, 0x0b);
+}
+
+
+#endif