rules.6809

# No need to add 0 to D
#1
	addd #0
=
====
# No need to in/decrease S by 0
#2
	leas -0,s
=
====
#3
	leas 0,s
=
====
# Avoid D reloads
#4
	std %1
	ldd %1
=
	std %1
====
#5
	std %1
;
	ldd %1
=
	std %1
====
#6
	std %1
;
;
	ldd %1
=
	std %1
====
# Avoid B reloads
#7
	stb %1
	ldb %1
=
	stb %1
====
#8
	stb %1
;
	ldb %1
=
	stb %1
====
#9
	stb %1
;
;
	ldb %1
=
	stb %1
====
# Avoid using a temporary
#10
	std R%1
	ldd %2
	addd R%1
=
	addd %2
====
# Use indexed addressing
#11
	ldx %1,s
	ldd 0,x
=
	ldd [%1,s]
====
#12
	ldx %1,s
	std 0,x
=
	std [%1,s]
====
#13
	ldx %1,s
	ldb 0,x
=
	ldb [%1,s]
====
#14
	ldx %1,s
	stb 0,x
=
	stb [%1,s]
====
# Some more indexed addressing
#15
	ldx %1,s
	ldd %2
	std 0,x
=
	ldd %2
	std [%1,s]
====
# Skip some D to X transfers
#16
	ldd %1
	tfr d,x
=
	ldx %1
====
# Get rid of silly jumps
#17
	bra L%1
;
L%1:
=
;
L%1:
====
#18
	bra L%1
L%1:
=
;
L%1:
====
# Skip some X to D transfers
#19
	tfr x,d
	std %1
=
	stx %1
====
# Lose some silly X index operations
#20
	ldx #%1
	ldd %2
	std 0,x
=
	ldd %2
	std %1
====
#21
	ldd #%1
	addd #%2
	tfr d,x
	ldd %3
	std 0,x
=
	ldd %3
	std %1+%2
====
#22
	ldx #%1
	ldd 0,x
=
	ldd %1
====
#23
	ldd #%1
	addd #%2
	tfr d,x
	ldd 0,x
=
	ldd %1+%2
====
# Simplify some X offsets
#24
	ldd %1
	addd #%2
	tfr d,x
	ldd %3
	std 0,x
=
	ldx %1
	ldd %3
	std %2,x
====
#25
	ldd %1
	addd #%2
	tfr d,x
	ldd 0,x
=
	ldx %1
	ldd %2,x
====
# Optmise << 1
#26
	pshs d
	ldd #1
	lbsr __shl
=
	aslb
	rola
====