progress on serial and added editor

dsa_resources/print.dsa

@@ -34,20 +34,34 @@ dw current: 0x20000
 // ------------------------------------------
 // prints the string at addr(arg[0]) to the screen.
 print: func
+    push rg0
+    push rg1
+    push rg2
+    push rg3
 
     ldw bpr, rg0, 8
     ldw current, rg1
 
 _print_loop:
     ldb rg0, rg2
-    ieq rg2, zero, rg4
-    jnz rg4, _end
+    ieq rg2, zero, rg3
+    jnz rg3, _print_end
     stb rg2, rg1
 
     addi rg0, 1
     addi rg1, 1
 
     jmp _print_loop
+
+_print_end:
+    stw rg1, current
+
+    pop rg3
+    pop rg2
+    pop rg1
+    pop rg0
+    return
+
 // ------------------------------------------
 // println:
 //     push bpr
@@ -99,11 +113,17 @@ _print_loop:
 // ------------------------------------------
 // prints the last byte of arg[0] to the screen.
 print_byte: func
+    push rg0
+    push rg1
+
     ldw bpr, rg0, 8
     ldw current, rg1
 
     stb rg0, rg1
     addi rg1, 1
+
+    pop rg1
+    pop rg0
     jmp _end
 
 // ------------------------------------------