; ------------------------------------
	; naive RAM and stack-based program:
	; 
	; 	(z-z)+(z=(2+(7-5))+x*(x=READ))+63*(y=READ)-(2+3*(8-4))
	;
	; total instruction count = 224
	; ------------------------------------
	
	; ------------------------------------
	; prologue: set up stack pointer in R9
	; ------------------------------------
	
	DATA xFF
	COPY DR,R9
	
	; ------------------------------------
	; main body of expression
	; (with some hand-made peephole optimizations)
	; ------------------------------------
	
	DATA #LITE			; Pushing 4
	LOAD R8,DR
	STORE R8,R9
	INC R9,-1
	DATA #LITI			; Pushing 8
	LOAD R8,DR
	STORE R8,R9
		; INC R9,-1
		; INC R9,1		; Doing -
	LOAD R8,R9
	INC R9,1
	LOAD R7,R9
	SUB R7,R8
	STORE R8,R9
	INC R9,-1
	DATA #LITD			; Pushing 3
	LOAD R8,DR
	STORE R8,R9
	INC R9,-1
	ZERO R4				; Doing *
	INC R9,1
	LOAD R0,R9
	INC R9,1
	LOAD R1,R9
	COPY R0,R2
	COPY R1,R3
	SHIFT R2, 5
	SHIFT R2, 6
	SHIFT R3, 5
	SHIFT R3, 6
	SUB R3,R2
		; SHIFT R0,-1
		; SHIFT R0, 1
		; SHIFT R1,-1
		; SHIFT R1, 1
	DATA #SKIPA
	COPY DR,J3
	DATA #LOOPA
	COPY DR,J2
	#LOOPA
	SET R3, 1
	AND R1,R3
	JPIF R3,EZ,J3
	ADD R0,R4
	#SKIPA
	SHIFT R0,-1
	SHIFT R1, 1
	JPIF R1,NZ,J2
	DATA #DONEA
	COPY DR,J3
	JPIF R2,EZ,J3
	ZERO R3
	SUB R4,R3
	COPY R3,R4
	#DONEA
	STORE R4,R9
	INC R9,-1
	DATA #LITC			; Pushing 2
	LOAD R8,DR
	STORE R8,R9
		; INC R9,-1
		; INC R9,1		; Doing +
	LOAD R8,R9
	INC R9,1
	LOAD R7,R9
	ADD R7,R8
	STORE R8,R9
	INC R9,-1
	READ R8,DD			; Reading input
	STORE R8,R9
	INC R9,-1
	DATA #VARY			; Putting y
	INC R9,1
	LOAD R8,R9
	STORE R8,DR
	INC R9,-1
	DATA #LITL			; Pushing 63
	LOAD R8,DR
	STORE R8,R9
	INC R9,-1
	ZERO R4				; Doing *
	INC R9,1
	LOAD R0,R9
	INC R9,1
	LOAD R1,R9
	COPY R0,R2
	COPY R1,R3
	SHIFT R2, 5
	SHIFT R2, 6
	SHIFT R3, 5
	SHIFT R3, 6
	SUB R3,R2
		; SHIFT R0,-1
		; SHIFT R0, 1
	SHIFT R1,-1
	SHIFT R1, 1
	DATA #SKIPB
	COPY DR,J3
	DATA #LOOPB
	COPY DR,J2
	#LOOPB
	SET R3, 1
	AND R1,R3
	JPIF R3,EZ,J3
	ADD R0,R4
	#SKIPB
	SHIFT R0,-1
	SHIFT R1, 1
	JPIF R1,NZ,J2
	DATA #DONEB
	COPY DR,J3
	JPIF R2,EZ,J3
	ZERO R3
	SUB R4,R3
	COPY R3,R4
	#DONEB
	STORE R4,R9
	INC R9,-1
	READ R8,DD			; Reading input
	STORE R8,R9
	INC R9,-1
	DATA #VARX			; Putting x
	INC R9,1
	LOAD R8,R9
	STORE R8,DR
	INC R9,-1
	DATA #VARX			; Getting x
	LOAD R8,DR
	STORE R8,R9
	INC R9,-1
	ZERO R4				; Doing *
	INC R9,1
	LOAD R0,R9
	INC R9,1
	LOAD R1,R9
	COPY R0,R2
	COPY R1,R3
	SHIFT R2, 5
	SHIFT R2, 6
	SHIFT R3, 5
	SHIFT R3, 6
	SUB R3,R2
	SHIFT R0,-1
	SHIFT R0, 1
	SHIFT R1,-1
	SHIFT R1, 1
	DATA #SKIPC
	COPY DR,J3
	DATA #LOOPC
	COPY DR,J2
	#LOOPC
	SET R3, 1
	AND R1,R3
	JPIF R3,EZ,J3
	ADD R0,R4
	#SKIPC
	SHIFT R0,-1
	SHIFT R1, 1
	JPIF R1,NZ,J2
	DATA #DONEC
	COPY DR,J3
	JPIF R2,EZ,J3
	ZERO R3
	SUB R4,R3
	COPY R3,R4
	#DONEC
	STORE R4,R9
	INC R9,-1
	DATA #LITF			; Pushing 5
	LOAD R8,DR
	STORE R8,R9
	INC R9,-1
	DATA #LITH			; Pushing 7
	LOAD R8,DR
	STORE R8,R9
		; INC R9,-1
		; INC R9,1		; Doing -
	LOAD R8,R9
	INC R9,1
	LOAD R7,R9
	SUB R7,R8
	STORE R8,R9
	INC R9,-1
	DATA #LITC			; Pushing 2
	LOAD R8,DR
	STORE R8,R9
		; INC R9,-1
		; INC R9,1		; Doing +
	LOAD R8,R9
	INC R9,1
	LOAD R7,R9
	ADD R7,R8
	STORE R8,R9
	INC R9,-1
	DATA #VARZ			; Putting z
	INC R9,1
	LOAD R8,R9
	STORE R8,DR
		; INC R9,-1
		; INC R9,1		; Doing +
	LOAD R8,R9
	INC R9,1
	LOAD R7,R9
	ADD R7,R8
	STORE R8,R9
	INC R9,-1
	DATA #VARZ			; Getting z
	LOAD R8,DR
	STORE R8,R9
	INC R9,-1
	DATA #VARZ			; Getting z
	LOAD R8,DR
	STORE R8,R9
		; INC R9,-1
		; INC R9,1		; Doing -
	LOAD R8,R9
	INC R9,1
	LOAD R7,R9
	SUB R7,R8
	STORE R8,R9
		; INC R9,-1
		; INC R9,1		; Doing +
	LOAD R8,R9
	INC R9,1
	LOAD R7,R9
	ADD R7,R8
	STORE R8,R9
		; INC R9,-1
		; INC R9,1		; Doing +
	LOAD R8,R9
	INC R9,1
	LOAD R7,R9
	ADD R7,R8
	STORE R8,R9
		; INC R9,-1
		; INC R9,1		; Doing -
	LOAD R8,R9
	INC R9,1
	LOAD R7,R9
	SUB R7,R8
	STORE R8,R9
	INC R9,-1
	
	; ------------------------------------
	; epilogue: final stack pop, write, halt
	; and literal and variable storage
	; ------------------------------------
	
	INC R9,1
	LOAD R0,R9
	WRITE R0,DD
	HALT
	
	#LITC	CONST 2
	#LITD   CONST 3
	#LITE   CONST 4
	#LITF	CONST 5
	#LITH   CONST 7
	#LITI   CONST 8
	#LITL   CONST 63
	
	#VARX   CONST 0
	#VARY   CONST 0
	#VARZ   CONST 0
	

	; ------------------------------------
	;	3FF 9E9 3D9 A8E B89 498 3DC A8E B89 A89 490 A79 778 B89 498 3D8
	;	A8E B89 498 140 490 A09 490 A19 902 913 524 525 534 535 732 327
	;	9ED 323 9EC 231 813 E3B 604 508 510 E1E 330 9ED E2B 130 743 934
	;	B49 498 3D7 A8E B89 A89 490 A79 678 B89 498 C80 B89 498 3DF 490
	;	A89 B8E 498 3DD A8E B89 498 140 490 A09 490 A19 902 913 524 525
	;	534 535 732 518 510 35D 9ED 359 9EC 231 813 E3B 604 508 510 E1E
	;	366 9ED E2B 130 743 934 B49 498 C80 B89 498 3DE 490 A89 B8E 498
	;	3DE A8E B89 498 140 490 A09 490 A19 902 913 524 525 534 535 732
	;	508 500 518 510 38C 9ED 388 9EC 231 813 E3B 604 508 510 E1E 395
	;	9ED E2B 130 743 934 B49 498 3DA A8E B89 498 3DB A8E B89 A89 490
	;	A79 778 B89 498 3D7 A8E B89 A89 490 A79 678 B89 498 3E0 490 A89
	;	B8E A89 490 A79 678 B89 498 3E0 A8E B89 498 3E0 A8E B89 A89 490
	;	A79 778 B89 A89 490 A79 678 B89 A89 490 A79 678 B89 A89 490 A79
	;	778 B89 498 490 A09 D00 000 002 003 004 005 007 008 03F 000 000
	;	000
	; ------------------------------------

	
	; ------------------------------------
	; a much shorter version, with algebraic optimization:
	;
	;	READ^2 + 63*READ - 10
	;
	; total instruction count = 25
	; ------------------------------------


	READ  R0,DD		; 1st input in R0
	
	COPY  R0,R1
	ADD   R1,R1		; 2 * R1
	ADD   R1,R1		; 4 * R1
	ADD   R1,R1		; 8 * R1
	ADD   R1,R1		; 16 * R1
	ADD   R1,R1		; 32 * R1
	ADD   R1,R1		; 64 * R1
	SUB   R0,R1		; 63 * R1
	
	INC   R1,-5		; -5 twice
	INC   R1,-5
	
	READ  R0,DD		; 2nd input in R0
	
	SHIFT R0,-1		; squaring R0
	SHIFT R0,1		; abs R0
	COPY  R0,R2		; R2 = R0
	COPY  PC,J0		; loop back in J0
	SET   R3, 1		; mask in R3
	AND   R2,R3		; get low bit R2
	ADD   R0,R1		; SPECULATIVE ADD directly to R1
	ADD   R3,PC		; jump over SUB if we had 1 bit
	SUB   R0,R1		; when 0 bit, compensatory SUB
	SHIFT R2, 1
	SHIFT R0,-1
	JPIF  R2,NZ,J0
	
	WRITE R1,DD
	HALT

	; ------------------------------------
	;	C00 901 611 611 611 611 611 611 701 419 C00 508 500 902 9FA 231
	;	823 601 63F 701 520 508 E2C D10 000
	; ------------------------------------


	; ------------------------------------
	; relative timings for inputs:
	;
	;	 5,   7:	245  vs.  39
	;	17,  31:	271  vs.  53
	;	-8, -15:	260  vs.  46
	; ------------------------------------