X-Git-Url: https://git.distorted.org.uk/~mdw/zx-fizzbuzz/blobdiff_plain/a221d644f4371212a32875ed05fa6dfafb31e51e..b4fd018059713a9efdaa72f9017a8d87b7dc7325:/fizzbuzz.s?ds=sidebyside

diff --git a/fizzbuzz.s b/fizzbuzz.s
index 58d4928..76242ef 100644
--- a/fizzbuzz.s
+++ b/fizzbuzz.s
@@ -2,21 +2,6 @@
 ;;;
 ;;; Best not to ask why.
 
-	org	0xf000
-
-print_a: equ	0x10
-tvflag:	equ	0x5c3c
-
-entry:
-	;; Initialize the buffer.
-	ld	a, 1
-	ld	(buf), a
-	ld	(len), a
-
-	;; Use the main screen.
-	xor	a
-	ld	(tvflag), a
-
 	;; Look at the buffer and decide what to do.
 again:	ld	e, 0
 
@@ -42,7 +27,7 @@ mod3_1:	djnz	mod3
 	call	squish
 	call	squish
 
-	cp	0
+	and	a
 	jr	z, prfizz
 	cp	3
 	jr	z, prfizz
@@ -68,14 +53,12 @@ prbuzz:	ld	hl, buzz
 
 	;; Not a multiple of five.  Skip ahead if it was a multiple of three.
 nobuzz:	ld	a, e
-	cp	0
+	and	a
 	jr	nz, prnl
 
 	;; OK, so just print the value.
-	ld	a, (len)
-	ld	b, 0
-	ld	c, a
 	ld	hl, buf - 1
+	ld	bc, (len)
 	add	hl, bc
 	ld	b, c
 
@@ -86,12 +69,12 @@ nobuzz:	ld	a, e
 	srl	a
 	srl	a
 	jr	z, skiplz
-	or	0x30
-	rst	print_a
+	fixdig
+	print_a
 skiplz:	ld	a, d
 	and	0x0f
-	or	0x30
-	rst	print_a
+	fixdig
+	print_a
 	dec	b
 	jr	z, prnl
 
@@ -102,17 +85,17 @@ prdig:	dec	hl
 	srl	a
 	srl	a
 	srl	a
-	or	0x30
-	rst	print_a
+	fixdig
+	print_a
 	ld	a, d
 	and	0x0f
-	or	0x30
-	rst	print_a
+	fixdig
+	print_a
 	djnz	prdig
 
 	;; Print the newline.
-prnl:	ld	a, ' '
-	rst	print_a
+prnl:	ld	a, spc
+	print_a
 
 	;; Increment the counter.
 	ld	hl, buf
@@ -128,14 +111,9 @@ incr:	ld	a, (hl)
 	djnz	incr
 
 	;; Carry out.
-	ld	a, (len)
-	ld	b, 0
-	ld	c, a
-	ld	hl, buf
-	add	hl, bc
 	ld	(hl), 1
-	inc	a
-	ld	(len), a
+	ld	hl, len
+	inc	(hl)
 	jp	again
 
 squish:
@@ -153,14 +131,13 @@ squish:
 print:
 	;; Print the string at hl.
 	ld	a, (hl)
-	cp	0
+	endstrp
 	ret	z
-	rst	print_a
+	print_a
 	inc	hl
 	jr	print
 
-fizz:	defb	"fizz", 0
-buzz:	defb	"buzz", 0
-
-len:	defb	0
-buf:	defs	256
+	;; Initial state.  The buffer notionally continues for another 254
+	;; bytes, but there's no point in including them in the image.
+len:	db	1, 0
+buf:	db	1