CGA cursor location

1 files changed, 41 insertions, 10 deletions

diff --git a/src/machine/cgascr.rs b/src/machine/cgascr.rs
index 091c50d..2748e67 100644
--- a/src/machine/cgascr.rs
+++ b/src/machine/cgascr.rs
@@ -1,4 +1,8 @@
-const vga_buffer:*mut u8 = 0xb8000 as *mut u8;
+use crate::arch::x86_64::io_port::*;
+
+const CGA_BUFFER_START:*mut u8 = 0xb8000 as *mut u8;
+const IR_PORT:u16 = 0x3d4;
+const DR_PORT:u16 = 0x3d5;
 
 #[allow(dead_code)]
 pub struct CGAScreen{
@@ -13,7 +17,7 @@ impl CGAScreen{
     }
 
    
-    fn get_index(&self,row:u32, col:u32) -> u32{
+    fn cal_offset(&self,row:u32, col:u32) -> u32{
         col + row*self.max_cows
     }
 
@@ -21,21 +25,48 @@ impl CGAScreen{
     // the memory by address. 
     // and since it's unsafe, it shouldn't be public
     pub fn show(&self, row:u32, col:u32, c:char, attr:u8){
-        let index = self.get_index(row, col);
+        let index = self.cal_offset(row, col);
 
         unsafe{
-            *vga_buffer.offset(index as isize * 2) = c as u8;
-            *vga_buffer.offset(index as isize * 2 + 1) = attr;
+            *CGA_BUFFER_START.offset(index as isize * 2) = c as u8;
+            *CGA_BUFFER_START.offset(index as isize * 2 + 1) = attr;
         }
 
     }
 
-    pub fn putchar(&self, ch:char){
-         
-    }
+    // pub fn putchar(&self, ch:char){
+    //      
+    // }
     
-    pub fn setpos(){}
-    pub fn getpos(){}
+    pub fn setpos(&self, row:u32, col:u32){
+        // io ports for instruction register and data register
+        let offset = self.cal_offset(row,col);
+        
+        // set lower byte
+        outb(IR_PORT, 15 as u8);
+        outb(DR_PORT, offset as u8);
+        // set higher byte
+        outb(IR_PORT, 14 as u8);
+        outb(DR_PORT, (offset >> 8) as u8);
+
+    }
+
+    pub fn getoffset() -> u32 {
+        // read higher byte
+        outb(IR_PORT, 14 as u8);
+        let mut offset = inb(DR_PORT);
+        offset = offset << 8;
+        // read lower byte
+        outb(IR_PORT, 15 as u8);
+        offset += inb(DR_PORT);
+        offset as u32
+    }
+
+    pub fn getpos(&self, row:& mut u32, cow:& mut u32){
+        let offset = Self::getoffset();
+        *row = offset % self.max_cows;
+        *cow = offset / self.max_cows;
+    }
      
 
     // Sanity Check of the cgascreen