Made screen.h actually good

src/kernel/main.c

@@ -3,6 +3,9 @@
 
 void main() {
     setupIdt();
-    print("kern.\n", 0x0f);
+    clear(0x0f);
+
+    print("kern.\n\n", 0x0f);
+    print("> ", 0x0e);
 }
 

src/kernel/screen.c

@@ -1,8 +1,15 @@
 #include "screen.h"
+#include "stdint.h"
 
-unsigned int cursor = 0;
+uint16_t cursor = 0;
 
-void putc(char c, char attr) {
+void putc(char c, uint8_t attr) {
+    if (c == '\n') {
+        uint16_t line = cursor - (cursor % COLS);
+        setCursorPos(line + COLS);
+        return;
+    }
+    
     int mem = VIDMEM + cursor * 2;
     *(char*)(mem) = c;
     *(char*)(mem+1) = attr;
@@ -10,12 +17,48 @@ void putc(char c, char attr) {
     cursor++;
 }
 
-void print(char* s, char attr) {
-    int i = 0;
+void print(char* s, uint8_t attr) { 
     char c = *s;
     while (c != '\0') {
         putc(c, attr);
-        c = *(s + ++i);
+        c = *(++s);
     }
 }
 
+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;
+    }
+}
+
+void setCursorPos(uint16_t offset) {
+    cursor = offset;
+}
+
+uint16_t getCursorPos() {
+    return cursor;
+}
+
+uint16_t calcOffset(uint8_t col, uint8_t row) {
+    return row * COLS + col;
+}
+

src/kernel/screen.h

@@ -1,9 +1,32 @@
 #ifndef SCREEN_H
 #define SCREEN_H
 
-#define VIDMEM 0xb8000
+#include "stdint.h"
 
-void putc(char c, char attr);
-void print(char* s, char attr);
+#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)
+
+#define CURSOR '_'
+
+void putc(char c, uint8_t attr);
+void print(char* s, uint8_t attr);
+void putcAt(char c, uint8_t attr, uint8_t row, uint8_t col);
+void printAt(char* s, uint8_t attr, uint8_t row, uint8_t col);
+void clear(uint8_t attr);
+
+void setCursorPos(uint16_t offset);
+uint16_t getCursorPos();
+uint16_t calcOffset(uint8_t row, uint8_t col);
+
+void setCursorChar(char cursor);
+char getCursorChar();
 
 #endif