Add _samples/fizzbuzz.{obj,asm}

_samples/fizzbuzz.asm

@@ -0,0 +1,96 @@
+	SET I, 1
+    SET Y, 0x8000
+:main
+	IFG I, 100
+		SET PC, end
+    IFG Y, 0x8179
+    	JSR scrollup
+	SET A, I
+	MOD A, 15
+	IFE A, 0
+		SET PC, fizzbuzz
+	SET A, I
+	MOD A, 5
+	IFE A, 0
+		SET PC, buzz
+	SET A, I
+	MOD A, 3
+	IFE A, 0
+		SET PC, fizz
+
+; print number
+	SET A, I
+    SET X, Y
+    SET PUSH, 0
+:loop
+	IFE A, 0
+    	SET PC, print
+    SET B, A
+    MOD B, 10
+    ADD B, 0x30 ; 30 is '0'
+    SET PUSH, B
+    DIV A, 10
+    SET PC, loop
+:print
+	SET A, POP
+	IFE A, 0
+    	SET PC, newline
+    SET [X], A
+    BOR [X], 0x7000 ; white text
+    ADD X, 1
+    SET PC, print
+:newline
+	ADD Y, 32
+    ADD I, 1
+    SET PC, main
+
+:printstr
+	SET X, Y
+:printstrloop
+	IFE [A], 0
+    	SET PC, newline
+    SET [X], [A]
+    BOR [X], 0x7000 ; white text
+    ADD X, 1
+    ADD A, 1
+    SET PC, printstrloop
+
+:fizz
+	SET A, fizzstr
+    SET PC, printstr
+:buzz
+	SET A, buzzstr
+    SET PC, printstr
+:fizzbuzz
+	SET A, fizzbuzzstr
+    set PC, printstr
+
+:fizzstr
+	DAT "Fizz", 0
+:buzzstr
+	DAT "Buzz", 0
+:fizzbuzzstr
+	DAT "FizzBuzz", 0
+
+:scrollup
+	SUB Y, 32
+    SET A, 0x8000
+    SET B, 0x8020
+:scrollloop
+	IFG B, 0x8179
+    	SET PC, scrollend
+    SET [A], [B]
+    ADD A, 1
+    ADD B, 1
+    SET PC, scrollloop
+:scrollend
+	; clear the last line
+    IFG A, 0x8179
+    	SET PC, POP
+    SET [A], 0
+    ADD A, 1
+    SET PC, scrollend
+
+:end
+	SET PC, end
+