1 files changed, 116 insertions, 0 deletions
diff --git a/include/screen.h b/include/screen.h
new file mode 100644
index 0000000..9d2873e
--- /dev/null
+++ b/include/screen.h
@@ -0,0 +1,116 @@
+#ifndef SCREEN_H
+#define SCREEN_H
+#include "types.h"
+#include "system.h"
+#include "string.h"
+int cursorX = 0, cursorY = 0;
+const uint8 sw = 80,sh = 25,sd = 2;                                                     //We define the screen width, height, and depth.
+void clearLine(uint8 from,uint8 to)
+{
+        uint16 i = sw * from * sd;
+        string vidmem=(string)0xb8000;
+        for(i;i<(sw*to*sd);i++)
+        {
+                vidmem[i] = 0x0;
+        }
+}
+void updateCursor()
+{
+    unsigned temp;
+
+    temp = cursorY * sw + cursorX;                                                      // Position = (y * width) +  x
+
+    outportb(0x3D4, 14);                                                                // CRT Control Register: Select Cursor Location
+    outportb(0x3D5, temp >> 8);                                                         // Send the high byte across the bus
+    outportb(0x3D4, 15);                                                                // CRT Control Register: Select Send Low byte
+    outportb(0x3D5, temp);                                                              // Send the Low byte of the cursor location
+}
+void clearScreen()
+{
+        clearLine(0,sh-1);
+        cursorX = 0;
+        cursorY = 0;
+        updateCursor();
+}
+
+void scrollUp(uint8 lineNumber)
+{
+        string vidmem = (string)0xb8000;
+        uint16 i = 0;
+        clearLine(0,lineNumber-1);                                            //updated
+        for (i;i<sw*(sh-1)*2;i++)
+        {
+                vidmem[i] = vidmem[i+sw*2*lineNumber];
+        }
+        clearLine(sh-1-lineNumber,sh-1);
+        if((cursorY - lineNumber) < 0 ) 
+        {
+                cursorY = 0;
+                cursorX = 0;
+        } 
+        else 
+        {
+                cursorY -= lineNumber;
+        }
+        updateCursor();
+}
+
+
+void newLineCheck()
+{
+        if(cursorY >=sh-1)
+        {
+                scrollUp(1);
+        }
+}
+
+void printch(char c)
+{
+    string vidmem = (string) 0xb8000;     
+    switch(c)
+    {
+        case (0x08):
+                if(cursorX > 0) 
+                {
+	                cursorX--;									
+                        vidmem[(cursorY * sw + cursorX)*sd]=0x00;	                              
+	        }
+	        break;
+       /* case (0x09):
+                cursorX = (cursorX + 8) & ~(8 - 1); 
+                break;*/
+        case ('\r'):
+                cursorX = 0;
+                break;
+        case ('\n'):
+                cursorX = 0;
+                cursorY++;
+                break;
+        default:
+                vidmem [((cursorY * sw + cursorX))*sd] = c;
+                vidmem [((cursorY * sw + cursorX))*sd+1] = 0x0F;
+                cursorX++; 
+                break;
+	
+    }
+    if(cursorX >= sw)                                                                   
+    {
+        cursorX = 0;                                                                
+        cursorY++;                                                                    
+    }
+    updateCursor();
+    newLineCheck();
+}
+
+void print (string ch)
+{
+        uint16 i = 0;
+        uint8 length = strlength(ch)-1;              //Updated (Now we store string length on a variable to call the function only once)
+        for(i;i<length;i++)
+        {
+                printch(ch[i]);
+        }
+}
+
+
+#endif