A examples/factorial8.xyw

@@ -0,0 +1,33 @@ 
+.include "devices.xyw"
+
+; ;ain program: calculate and print factorial of 5
+$5 fact JSRw 
+print8 JSRw
+$0A terminal.output STB
+end JMPw
+
+; Factorial subroutine
+; a8 -- | [xy]
+.label fact
+  ; Save argument to both registers
+  POPxy
+  .label fact.loop 
+    PSHy $0 EQU fact.end0 JCNw
+    PSHy $1 EQU fact.end1 JCNw
+    ; Decrement y and multiply
+    DECy PSHx PSHy MULx POPx
+    fact.loop JMPw
+  .label fact.end0
+    ; Edge case: factorial of 0 is 1
+    $1
+    CLRxy
+    RTS
+  .label fact.end1
+    ; Return result
+    PSHx
+    CLRxy
+    RTS
+
+.include "print8.xyw"
+
+.label end

A examples/print16.xyw

@@ -0,0 +1,28 @@ 
+.include "devices.xyw"
+
+$321 print16 JSRw
+$0A terminal.output STB
+end JMPw
+ 
+; Printing subroutine
+; a16 -- | [xw]
+.label print16
+  POPxw 
+  ; If value is less than 10, print single digit
+  ; Push 16-bit literal as two bytes (high, low), then compare
+  PSHxw $00 $0A LTHw SWP POP print16.single JCNw
+  ; Divide by 10, stack becomes [remainder, quotient] with quotient on top
+  PSHxw $00 $0A DIVw
+  ; Call print16 recursively with quotient (on top, consumed by POPxw)
+  print16 JSRw
+  ; Remainder (16-bit) is still on stack, get low byte and print it
+  SWP POP $30 ADD terminal.output STB
+  CLRxw
+  RTS
+  .label print16.single
+    ; Print single digit (need low byte of XW since value is 0-9)
+    PSHxw SWP POP $30 ADD terminal.output STB
+    CLRxw
+    RTS
+
+.label end

A examples/print8.xyw

@@ -0,0 +1,23 @@ 
+; Assumes .include "devices.xyw"
+ 
+; Printing subroutine
+; a8 -- | [xy]
+.label print8
+  POPx 
+  ; If value is less than 10, print single digit
+  PSHx $A LTH print8.single JCNw
+  ; Divide by 10: stack becomes [remainder, quotient]
+  PSHx $A DIV
+  ; Save remainder to y for later
+  SWP POPy
+  ; Call print8 recursively with quotient (still on stack)
+  print8 JSRw
+  ; Print the saved remainder
+  PSHy $30 ADD terminal.output STB
+  CLRxy
+  RTS
+  .label print8.single
+    ; Print single digit
+    PSHx $30 ADD terminal.output STB 
+    CLRx
+    RTS

M test.sh → test.sh

@@ -7,7 +7,7 @@ "run_test helloworld.xyw assert_output_equals \$'Hello, World!\\n'"
   "run_test d6.xyw assert_output_in_range 1 6"
   "run_test on-error.xyw assert_output_equals \$'Error: Division by zero.\\nError: Unknown error.\\n'"
   "run_test print-args.xyw test1 test2 -- assert_output_equals \$'print-args.xim, test1, test2\\n'"
-  "run_test factorial.xyw assert_output_equals \$'120\\n'"
+  "run_test factorial8.xyw assert_output_equals \$'120\\n'"
 )
 
 ### Helper functions