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

1 files changed, 70 insertions, 0 deletions

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\:\ \