Added new instructions.

Added CCF - Clear Carry Flag
Added BRC - Branch on Carry Flag
Improved CALL and RET - All registers but status now saved and restored.

Programs/printHello.asm

@@ -8,13 +8,25 @@
 #Include print.asm
 
 #Program
-  Start:
-    SETD myString       ; Set the Data Pointer to the string we want to print.
-    CALL printString    ; Call the subroutine.
-    CALL lineFeed       ; Call the linefeed subroutine.
-    HALT                ; Stop the CPU.
+
+start:
+  SETD MyString           ; Set the Data Pointer to the start of MyString.
+  CALL printString        ; Call the string printing subroutine.
+  CALL lineFeed           ; Call the line feed subroutine to end the line.
+  SETD MyDecimal          ; Set the Data Pointer to the value to print as a decimal.
+  CALL printDecimal       ; Call the decimal printing subroutine.
+  SETD MyMessage          ; Set the Data Pointer to another string.
+  CALL printString        ; Call the string printing subroutine again.
+  CALL lineFeed           ; Call the line feed subroutine to end the line.
+  HALT                    ; Stop the program.
 
 #Data
 
-myString:
-  "Hello, World!"
+MyString:
+  "Hello, World! "
+
+MyDecimal:
+  0d42
+
+MyMessage:
+  " is the great answer."