diff --git a/gr-sim/tfv_flying_6502.c b/gr-sim/tfv_flying_6502.c
index fef4fc8b..fe161594 100644
--- a/gr-sim/tfv_flying_6502.c
+++ b/gr-sim/tfv_flying_6502.c
@@ -99,15 +99,29 @@ struct cycle_counts {
 	int put_sprite;
 } cycles;
 
+static int last_color=0,last_xx=0,last_yy=0;
+
 static int lookup_map(int xx, int yy) {
 
 	int color,offset;
 
-	color=2;
+	/* cache last value */
+				cycles.lookup_map+=9;
+	if (yy==last_yy) {
+				cycles.lookup_map+=8;
+		if (xx==last_xx) {
+				cycles.lookup_map+=8;
+			return last_color;
+		}
+	}
 
+	last_xx=xx;
 	xx=xx&MASK_X;
+
+	last_yy=yy;
 	yy=yy&MASK_Y;
 
+
 	if (!displayed) {
 		printf("XX,YY! %x,%x\n",xx,yy);
 	}
@@ -119,24 +133,32 @@ static int lookup_map(int xx, int yy) {
 	offset=yy<<3;
 	offset+=xx;
 
-//	color=water_map[((yy*8)+xx)&0x1f];
-	color=water_map[offset&0x1f];
+				cycles.lookup_map+=37;
+
+	if ((yy>7) || (xx>7)) {
+			cycles.lookup_map+=14;
+		color=water_map[offset&0x1f];
+			cycles.lookup_map+=11;
+		goto update_cache;
+
+	}
 
 	/* 2 2 2 2  2 2 2 2 */
 	/* e 2 2 2  2 2 2 2 */
 	/* 2 2 2 2  2 2 2 2 */
 	/* 2 2 2 2  e 2 2 2 */
 
-	if ((yy<8) && (xx<8)) {
-		color=flying_map[offset];
-	}
+	color=flying_map[offset];
+				cycles.lookup_map+=8;
 
 	if (!displayed) {
 		printf("COLOR! %x\n",color);
 	}
 
 
-			cycles.lookup_map+=53;
+update_cache:
+				cycles.lookup_map+=9;
+	last_color=color;
 	return color;
 }
 
diff --git a/tfv/OPTIMIZATION b/tfv/OPTIMIZATION
index 6b072d65..66d11c4d 100644
--- a/tfv/OPTIMIZATION
+++ b/tfv/OPTIMIZATION
@@ -58,3 +58,16 @@ Update to optimize fast multiply (reusing NUM1H, return results in register)
         Total =                  135,575
 	Frame Rate = 7.38 fps
 
+Add a cache to lookup_map
+
+	Cycles: flying=              162
+	Cycles: getkey=               46
+	Cycles: page_flip=            26
+	Cycles: multiply=         24,935
+	Cycles: mode7=            73,445
+	Cycles: lookup_map=       24,649
+	Cycles: put_sprite=        2,561
+	=================================
+	Total =                  125,824
+	Frame Rate = 7.95 fps
+
diff --git a/tfv/tfv_flying.s b/tfv/tfv_flying.s
index 67650cb9..f9d3d5ba 100644
--- a/tfv/tfv_flying.s
+++ b/tfv/tfv_flying.s
@@ -12,7 +12,7 @@ CONST_BETA_F	EQU	$80
 CONST_SCALE_I	EQU	$14
 CONST_SCALE_F	EQU	$00
 CONST_LOWRES_HALF_I	EQU	$ec	; -(LOWRES_W/2)
-CONST_LOWRES_HALF_F	EQU	$00	
+CONST_LOWRES_HALF_F	EQU	$00
 
 flying_start:
 
@@ -955,11 +955,27 @@ done_screeny:
 	; finds value in space_x.i,space_y.i
 	; returns color in A
 lookup_map:
+
+	; cache color and return if same as last time
+	lda	SPACEY_I			; 3
+	cmp	LAST_SPACEY_I			; 3
+	bne	nomatch				; 2nt/3
+	lda	SPACEX_I			; 3
+	cmp	LAST_SPACEX_I			; 3
+	bne	nomatch2			; 2nt/3
+	lda	LAST_MAP_COLOR			; 3
+	rts					; 6
+
+nomatch:
 	lda	SPACEX_I						; 3
+nomatch2:								; 3
+	sta	LAST_SPACEX_I						; 3
 	and	#CONST_MAP_MASK						; 2
 	sta	TEMPY							; 3
+	tay								; 2
 
 	lda	SPACEY_I						; 3
+	sta	LAST_SPACEY_I						; 3
 	and	#CONST_MAP_MASK		; wrap to 64x64 grid		; 2
 
 
@@ -967,28 +983,31 @@ lookup_map:
 	asl								; 2
 	asl				; multiply by 8			; 2
 	clc								; 2
-	adc	TEMPY			; add in X value		; 2
-					; (use OR instead?)
+	adc	TEMPY			; add in X value		; 3
+					; only valid if x<8 and y<8
 
-	ldy	SPACEX_I						; 3
-	cpy	#$8							; 2
-	beq	ocean_color		; bgt				; 2nt/3
-	bcs	ocean_color						; 2nt/3
+	; SPACEX_I is in y
+	cpy	#$9							; 2
+								;============
+								;	 37
+
+	bcs	ocean_color		; bgt 8				; 2nt/3
 	ldy	SPACEY_I						; 3
-	cpy	#$8							; 2
-	beq	ocean_color		; bgt				; 2nt/3
-	bcs	ocean_color						; 2nt/3
+	cpy	#$9							; 2
+	bcs	ocean_color		; bgt 8				; 2nt/3
 
 	tay								; 2
 	lda	flying_map,Y		; load from array		; 4
 
-	rts								; 6
+	bcc	update_cache						; 3
 
 ocean_color:
 	and	#$1f							; 2
 	tay								; 2
 	lda	water_map,Y		; the color of the sea		; 4
 
+update_cache:
+	sta	LAST_MAP_COLOR						; 3
 	rts								; 6
 
 flying_map:
diff --git a/tfv/tfv_zp.inc b/tfv/tfv_zp.inc
index df8f6d0e..95370314 100644
--- a/tfv/tfv_zp.inc
+++ b/tfv/tfv_zp.inc
@@ -89,7 +89,10 @@ NUM1H		EQU	$7F
 NUM2L		EQU	$80
 NUM2H		EQU	$81
 RESULT		EQU	$82 ; 83,84,85
-NEGATE		EQU	$86
+NEGATE		EQU	$86			; UNUSED?
+LAST_SPACEX_I	EQU	$87
+LAST_SPACEY_I	EQU	$88
+LAST_MAP_COLOR	EQU	$89
 
 SHIPY           EQU     $E4