add printch to screen

vaja2/zaslon/screen.asm

@@ -8,7 +8,16 @@ SCREEN START 0
     LDA #88 
     JSUB scrfill
     JSUB scrclear 
-
+    LDA #99
+    STA znak
+    LDA #25 
+    STA row
+    LDA #30
+    STA col
+    JSUB printch
+    LDA #30
+    STA row
+    JSUB printch
 HALT J HALT
     END SCREEN
 
@@ -67,7 +76,24 @@ loop_clear  LDA y
             STA y
             LDA old_val
             RSUB        
-  
+
+printch STA old_val
+        LDA row
+        MUL scrcols
+        ADD screen
+        ADD col 
+        STA pix_ptr
+        LDA znak
+        STCH @pix_ptr
+
+        CLEAR A
+        LDA old_val 
+        RSUB
+        
+
+
+row WORD 0 
+col WORD 0 
 old_val WORD 0 
 znak WORD 0 
 x WORD 0