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/printDecimalTest.asm

@@ -0,0 +1,31 @@
+; Tests for the printDecimal subroutine.
+
+#Include print.asm
+
+#Program
+
+start:
+  INIB 0xFF         ; Load 255 into B.
+ loop:
+  SETD MyDecimal    ; Set D to our decimal.
+  SUB
+  CCF               ; Clear the Carry Flag.
+  CALL printDecimal ; Print the value.
+  LDA               ; Load the value into A.
+  INCA              ; Increment it.
+  STA               ; Store it again.
+  SETD Space
+  CALL printString  ; Print a space between the the numbers.
+  BRQ end           ; If Q is zero, we're done.
+  BRI loop          ; Branch back to the start of the loop.
+ end:
+  CALL lineFeed
+  HALT
+
+#Data
+
+MyDecimal:
+  0x00
+
+Space:
+  " "