feat(catalan): Implement catalan and move math subroutines to a separate file

2 files changed, 120 insertions, 101 deletions

diff --git a/catalan/catalan.a65 b/catalan/catalan.a65
index 36cf7c1..1a04a3e 100644
--- a/catalan/catalan.a65
+++ b/catalan/catalan.a65
@@ -1,123 +1,72 @@
 #include "basic_starter.a65"
 #include "kernal.a65"
+#include "math.a65"
 
 hello	.byt "HELLO, WORLD!",0
 
-// accumulator = a * b
-#define multiply(a, b) .(                     :\
-	lda a       ; if (a == 0)             :\
-	beq return  ;   return 0              :\
-	sta buffer  ; buffer = a              :\
-                                               \
-	lda b       ; if (b == 0)             :\
-	beq return  ;   return 0              :\
-	tax         ; x = b                   :\
-                                               \
-	lda #0      ; a = 0                   :\
-loop	clc         ; do  carry = 0           :\
-	adc buffer  ;     a += buffer + carry :\
-	dex         ;     --x                 :\
-	cpx #0      ; while (x > 0)           :\
-	bne loop                              :\
-return                                        :\
-.)
-
-// accumulator = a / b
-#define divide(a, b) .(                        :\
-	lda b       ; if (b == 0)              :\
-	beq return  ;   return 0               :\
-	sta buffer  ; buffer = b               :\
-                                                \
-	lda a       ; if (a == 0)              :\
-	beq return  ;   return 0               :\
-	ldx #0      ; x = 0                    :\
-                                                \
-loop	sec         ; do  carry = 1            :\
-	sbc buffer  ;     a -= buffer + !carry :\
-	inx         ;     ++x                  :\
-	cmp buffer  ; while (a >= buffer)      :\
-	bcs loop                               :\
-return  txa                                    :\
-.)
 
-cat_n	.byt 1
-n	.byt 0
-
-main
-	lda #9
-	sta diva_arg1
-	lda #144
-	jsr diva
-	clc
-	adc #49
+main .(
+	jsr catalan
+	lda cat_n
 	putchar()
 	rts
-
-// a *= multa_arg1
-multa .(
-	ora #0		; Update flags, so they're accurate with the accumulator value
-	beq return	; if (a == 0) return a
-	cmp #1		; if (a == 1)
-	beq r_arg1	;   return arg1
-
-	ldx arg1	; x = arg1
-	cpx #0		; if (x == 0)
-	beq r_zero	;   return 0
-	cpx #1		; if (x == 1)
-	beq return	;   return a
-
-	dex		; --x  // accumulator already has the first value
-	sta addend	; addend = a
-loop	clc		; do  carry = 0
-	adc addend	;     a += addend + carry
-	dex		;     --x
-	cpx #1		; while (x >= 1)
-	bcs loop
-
-return	ora #0		; Update flags, so they're accurate with the accumulator value
-	rts
-
-r_zero	lda #0
-	rts
-
-r_arg1	lda arg1
-	rts
-
-+multa_arg1
-arg1		.byt 0
-addend		.byt 0
 .)
 
-// a /= diva_arg1
-diva .(
-	ora #0		; Update flags, so they're accurate with the accumulator value
-	beq return	; if (a == 0) return a
+#define store_in_memory(memory, value) .( :\
+	pha		; push a          :\
+	lda value	; a = value       :\
+	sta memory	; memory = a      :\
+	pla		; pop a           :\
+.)
 
-	ldx arg1	; x = arg1
-	cpx #0		; if (x == 0)
-	beq r_zero	;   return 0
-	cpx #1		; if (x == 1)
-	beq return	;   return a
+/* a = x
+ * a *= 4
+ * a -= 2
+ * b = x
+ * ++b
+ * a /= b
+ * a *= cat_n
+ * cat_n = a
+ */
+catalan .(
+	lda n		; a = n
+	cmp #1		; if (a < 1)
+	bcc return	;   return
 
-	stx subtrahend	; subtrahend = x
 	ldx #0		; x = 0
-loop	sec		; do  carry = 1
-	sbc subtrahend	;     a -= addend + !carry
+loop	inx		; do  ++x
+
+	txa		;     a = x
+			;     a *= 4
+	store_in_memory(multa_arg1, #4)
+	jsr multa
+	sec		;     a -= 2
+	sbc #2
+
 	inx		;     ++x
-	cmp subtrahend	; while (a >= subtrahend)
-	bcs loop
+	stx divisor	;     divisor = x
+	dex		;     --x
 
-return	txa
-	rts
+			;     a /= divisor
+	store_in_memory(diva_arg1, divisor)
+	jsr diva
+			;     a *= cat_n
+	store_in_memory(multa_arg1, cat_n)
+	jsr multa
+	sta Cn 		;     Cn = a
 
-r_zero	lda #0
-	rts
+	cpx n		; while (x < n)
+	bcc loop
+return	rts
 
-+diva_arg1
-arg1		.byt 0
-subtrahend	.byt 0
++cat_Cn
+Cn	.byt 1
++cat_n
+n	.byt 0
+divisor	.byt 0
 .)
 
+
 buffer	.byt 0
 
 // vim: noet ts=8 sw=0 lcs=tab\:\ \ 
diff --git a/catalan/math.a65 b/catalan/math.a65
new file mode 100644
index 0000000..ea45675
--- /dev/null
+++ b/catalan/math.a65
@@ -0,0 +1,70 @@
+#ifndef CATALAN_MATH
+#define CATALAN_MATH
+
+; a *= multa_arg1
+multa .(
+	ora #0		; Update flags, so they're accurate with the accumulator value
+	beq return	; if (a == 0) return a
+	cmp #1		; if (a == 1)
+	beq r_arg1	;   return arg1
+
+	ldx arg1	; x = arg1
+	cpx #0		; if (x == 0)
+	beq r_zero	;   return 0
+	cpx #1		; if (x == 1)
+	beq return	;   return a
+
+	dex		; --x  // accumulator already has the first value
+	sta addend	; addend = a
+loop	clc		; do  carry = 0
+	adc addend	;     a += addend + carry
+	dex		;     --x
+	cpx #1		; while (x >= 1)
+	bcs loop
+
+return	ora #0		; Update flags, so they're accurate with the accumulator value
+	rts
+
+r_zero	lda #0
+	rts
+
+r_arg1	lda arg1
+	rts
+
++multa_arg1
+arg1		.byt 0
+addend		.byt 0
+.)
+
+; a /= diva_arg1
+diva .(
+	ora #0		; Update flags, so they're accurate with the accumulator value
+	beq return	; if (a == 0) return a
+
+	ldx arg1	; x = arg1
+	cpx #0		; if (x == 0)
+	beq r_zero	;   return 0
+	cpx #1		; if (x == 1)
+	beq return	;   return a
+
+	stx subtrahend	; subtrahend = x
+	ldx #0		; x = 0
+loop	sec		; do  carry = 1
+	sbc subtrahend	;     a -= addend + !carry
+	inx		;     ++x
+	cmp subtrahend	; while (a >= subtrahend)
+	bcs loop
+
+return	txa
+	rts
+
+r_zero	lda #0
+	rts
+
++diva_arg1
+arg1		.byt 0
+subtrahend	.byt 0
+.)
+
+#endif /* CATALAN_MATH */
+// vim: noet ts=9 sw=0 lcs=tab\:\ \