diff --git a/.gitignore b/.gitignore
index 57794ad..0829c50 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@
 /gscats.lst
 /GSCats.xcodeproj/xcuserdata/qd.xcuserdatad/xcdebugger
 /loader.lst
+/terrain_e1.lst
diff --git a/GSCats.xcodeproj/project.pbxproj b/GSCats.xcodeproj/project.pbxproj
index 099a370..875780a 100644
--- a/GSCats.xcodeproj/project.pbxproj
+++ b/GSCats.xcodeproj/project.pbxproj
@@ -13,6 +13,7 @@
 		700F21E01F4A3A5500D7007D /* GenerateTrigTables.py */ = {isa = PBXFileReference; lastKnownFileType = text.script.python; path = GenerateTrigTables.py; sourceTree = "<group>"; };
 		700FFAFB1F40F3BF00A442DE /* font.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = font.s; sourceTree = "<group>"; };
 		7059502B1F37A0BE00BBE90F /* GenerateVRAMTable.py */ = {isa = PBXFileReference; lastKnownFileType = text.script.python; path = GenerateVRAMTable.py; sourceTree = "<group>"; };
+		705AAFA920040B0D001BB0ED /* terrain_e1.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = terrain_e1.s; sourceTree = "<group>"; };
 		706DF1641F2D39F700AA6680 /* loader.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = loader.s; sourceTree = "<group>"; };
 		706DF1651F2D4A8100AA6680 /* terrain.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = terrain.s; sourceTree = "<group>"; };
 		7088096D1F2ECE8D00D4C950 /* GenerateRenderSpans.py */ = {isa = PBXFileReference; lastKnownFileType = text.script.python; path = GenerateRenderSpans.py; sourceTree = "<group>"; };
@@ -20,6 +21,8 @@
 		7099E3841F41022100182A82 /* gameobject.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = gameobject.s; sourceTree = "<group>"; };
 		7099E3851F4107B100182A82 /* GenerateVRAMYOffset.py */ = {isa = PBXFileReference; lastKnownFileType = text.script.python; path = GenerateVRAMYOffset.py; sourceTree = "<group>"; };
 		70A80FB01F43D7F200BD34C9 /* gamemanager.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = gamemanager.s; sourceTree = "<group>"; };
+		70BDCBC92006AD5F00CB51F1 /* linkerConfig */ = {isa = PBXFileReference; lastKnownFileType = text; path = linkerConfig; sourceTree = "<group>"; };
+		70BDCBCA200A99F200CB51F1 /* ParseMapFile.py */ = {isa = PBXFileReference; lastKnownFileType = text.script.python; path = ParseMapFile.py; sourceTree = "<group>"; };
 		70C073091F5BAA3E009844A9 /* collision.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = collision.s; sourceTree = "<group>"; };
 		70E266E31F6F262D005AC7E4 /* circleTable.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = circleTable.s; sourceTree = "<group>"; };
 		70E554C41F807ADB00F3C871 /* spritebank.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = spritebank.s; sourceTree = "<group>"; };
@@ -45,6 +48,7 @@
 				706DF1641F2D39F700AA6680 /* loader.s */,
 				700FFAFB1F40F3BF00A442DE /* font.s */,
 				706DF1651F2D4A8100AA6680 /* terrain.s */,
+				705AAFA920040B0D001BB0ED /* terrain_e1.s */,
 				70C073091F5BAA3E009844A9 /* collision.s */,
 				70F086A01F4230CB002446C3 /* utility.s */,
 				700C39C51F2E5CA800C24F9C /* tables.s */,
@@ -55,12 +59,14 @@
 				70E554C41F807ADB00F3C871 /* spritebank.s */,
 				70E9D8611F2BD95400555C19 /* gscats.s */,
 				70E9D8631F2BD95400555C19 /* Makefile */,
+				70BDCBC92006AD5F00CB51F1 /* linkerConfig */,
 				70FE79D21F8814A600E0095C /* MerlinToCA65.sh */,
 				7088096D1F2ECE8D00D4C950 /* GenerateRenderSpans.py */,
 				7059502B1F37A0BE00BBE90F /* GenerateVRAMTable.py */,
 				7099E3851F4107B100182A82 /* GenerateVRAMYOffset.py */,
 				700F21E01F4A3A5500D7007D /* GenerateTrigTables.py */,
 				709175C01F60D263008FAFAB /* GenerateCircles.py */,
+				70BDCBCA200A99F200CB51F1 /* ParseMapFile.py */,
 			);
 			sourceTree = "<group>";
 		};
diff --git a/Makefile b/Makefile
index 2b99679..fdc23eb 100644
--- a/Makefile
+++ b/Makefile
@@ -18,18 +18,21 @@ MRSPRITE=../MrSprite/mrsprite
 CHROMA=00ff00
 PALETTE=a4dffb 008800 886611 cc9933 eebb44 dd6666 ff99aa 000000 0e7db1 ffff00 ffff00 ffff00 ffff00 ffff00 ffff00 ffffff
 SPRITES=SpriteBank
+REMOTESYMBOLS=-Wl $(shell ./ParseMapFile.py *.map)
 
-all: $(PGM) loader
+all: terrain_e1 $(PGM) loader
 
 
 $(PGM):
-	@PATH=$(PATH):/usr/local/bin; $(CL65) -t apple2enh --cpu 65816 --start-addr 0000 -l$(PGM).lst $(PGM).s
+	@echo $(REMOTESYMBOLS)
+	@PATH=$(PATH):/usr/local/bin; $(CL65) -t apple2enh -C linkerConfig --cpu 65816 --start-addr 0000 -l$(PGM).lst $(REMOTESYMBOLS) $(PGM).s
 	java -jar $(AC) -d $(PGM).2mg CODEBANK
 	java -jar $(AC) -p $(PGM).2mg CODEBANK BIN 0x0000 < $(PGM)
 	java -jar $(AC) -d $(PGM).2mg $(SPRITES)00
 	java -jar $(AC) -p $(PGM).2mg $(SPRITES)00 BIN 0x0000 < $(SPRITES)00.bin
 	rm -f $(PGM)
 	rm -f $(PGM).o
+	rm -f terrain_e1.map
 	osascript V2Make.scpt $(PROJECT_DIR) $(PGM)
 
 loader:
@@ -39,11 +42,21 @@ loader:
 	rm -f loader
 	rm -f loader.o
 
+terrain_e1:
+	@PATH=$(PATH):/usr/local/bin; $(CL65) -t apple2enh -C linkerConfig --cpu 65816 --start-addr $(ADDR) -l -vm -m terrain_e1.map terrain_e1.s
+	java -jar $(AC) -d $(PGM).2mg CODEBANKE1
+	java -jar $(AC) -p $(PGM).2mg CODEBANKE1 BIN 0x800 < terrain_e1
+	rm -f terrain_e1
+	rm -f terrain_e1.o
+
 clean:
 	rm -f $(PGM)
 	rm -f $(PGM).o
 	rm -f loader
 	rm -f loader.o
+	rm -f terrain_e1.o
+	rm -f terrain_e1.map
+	rm -f terrain_e1
 
 .PHONY: art
 art:
diff --git a/ParseMapFile.py b/ParseMapFile.py
new file mode 100755
index 0000000..b9ed593
--- /dev/null
+++ b/ParseMapFile.py
@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+
+# Outputs a list of exported symbols found in an ld65 link map file
+# suitable for passing as a commandline option to define those
+# same symbols in a cl65 compile/assemble operation. This allows
+# sharing symbols between code banks without having to actually
+# link them together. Sort of a low-budget DLL mechanism. :)
+
+import sys
+
+
+def parseInputFile(filename,bank):
+
+	inputFile = open(filename)
+	contents = inputFile.readlines()
+	output = ""
+
+	# Find exported symbols
+	lineNum = 0
+	for line in contents:
+		if line.find("Exports list") != -1:
+			break
+		lineNum+=1
+
+	# Found the exports table, so look for our symbol names
+	first=1
+	for line in contents[lineNum+1:]:
+		if line.startswith("_") or line.startswith("-"):
+			continue
+		if line.startswith("Imports") or len(line)<2:
+			break
+
+		if first!=1:
+			output += ","
+		first = 0
+
+		columns = line.split()
+		if len(columns) > 3:
+			output += ("-D,%s=0x%s,-D,%s=0x%s" % (columns[0],bank+columns[1][2:],columns[3],bank+columns[4][2:]))
+		else:
+			output += ("-D,%s=0x%s" % (columns[0],bank+columns[1][2:]))
+
+	inputFile.close()
+	return output
+
+
+def main(argv):
+	commandline = ""
+	first=1
+
+	for file in argv:
+
+		if first!=1:
+			commandline += ","
+		first = 0
+
+		bank = file[-6:-4]		# Assumes filename_XX.map
+		commandline += parseInputFile(file,bank)
+
+	print (commandline)
+
+
+if __name__ == "__main__":
+	main(sys.argv[1:])
diff --git a/collision.s b/collision.s
index 5ae9c71..91c0249 100644
--- a/collision.s
+++ b/collision.s
@@ -50,7 +50,7 @@ intersectRectTerrain:
 
 	; Check Y bottom
 intersectRectTerrainBottomLoop:
-	lda terrainData,y
+	lda terrainDataFar,y
 	cmp rectParams+6
 	bpl intersectRectTerrainYep
 	dey
diff --git a/equates.s b/equates.s
index a6e9dc1..8f7b9ae 100644
--- a/equates.s
+++ b/equates.s
@@ -28,6 +28,26 @@ SCRATCHL2		= $67		; Second 16-bit scratch
 PARAM24			= $67		; 24-bit param (This is almost certainly messing up AppleSoft, but meh)
 CACHEPTR		= $6A		; General purpose cache pointer (This is almost certainly messing up AppleSoft, but meh)
 CACHEDATA		= $6C		; General purpose cache data (This is almost certainly messing up AppleSoft, but meh)
+leftScreenEdge	= $6E		; Reserved for leftScreenEdge  (This is almost certainly messing up AppleSoft, but meh)
 STACKPTR		= $70		; Cache for stack pointer in fast graphics
 SHADOWREGISTER	= $72		; Cache for shadow register in fast graphics
 STACKREGISTER	= $73		; Cache for stack register in fast graphics
+
+
+; Terrain constants
+TERRAINWIDTH = 640		; In pixels
+MAXTERRAINHEIGHT = 100	; In pixels
+COMPILEDTERRAINROW = TERRAINWIDTH/4+3	; In words, +2 to make room for clipping jump at end of row
+VISIBLETERRAINWIDTH = TERRAINWIDTH/4	; In words- width minus jump return padding
+VISIBLETERRAINWINDOW = 80				; In words
+MAXSPANSPERROW = 15
+SPANROWBYTES = MAXSPANSPERROW*2 + 2		; In bytes
+
+
+; Terrain data, stored as height values 2 pixels wide (bytes)
+terrainDataFar = $02f500
+terrainData = $f500
+;	.repeat TERRAINWIDTH/2
+;	.word 0
+;	.endrepeat
+terrainDataEnd = terrainData + (TERRAINWIDTH/2 * 2)
diff --git a/gamemanager.s b/gamemanager.s
index 64b3dc9..acb0f02 100644
--- a/gamemanager.s
+++ b/gamemanager.s
@@ -27,11 +27,13 @@ beginGameplay:
 	jsr colorFill
 
 	; Generate, compile, and clip terrain
+	stz leftScreenEdge
 	jsr generateTerrain
-	jsr compileTerrainSpans
+
+	jsl compileTerrainSpans
 ;	jsr compileTerrain
 ;	jsr clipTerrain
-	jsr renderTerrainSpans
+	jsl renderTerrainSpans
 
 	; Create players
 	lda #56
@@ -58,8 +60,8 @@ gameplayLoop:
 ;	lda terrainDirty
 ;	beq gameplayLoopKbd
 	BORDER_COLOR #$3
-	jsr unrenderTerrainSpans
-	jsr renderTerrainSpans
+	jsl unrenderTerrainSpans
+	jsl renderTerrainSpans
 
 	stz terrainDirty
 	BORDER_COLOR #$1
@@ -334,7 +336,7 @@ paused:
 ; c) Byte-distance from left edge of logical terrain to right edge of visible screen minus game object width in words
 mapScrollPos:
 	.word 0
-leftScreenEdge:
-	.word 0
+;leftScreenEdge = $6E		; Moved to zero page for speed and cross-bank convenience
+;	.word 0
 rightScreenEdge:
 	.word 160-GAMEOBJECTWIDTH/4-1
diff --git a/gscats.2mg b/gscats.2mg
index e9d254f..52f8229 100644
Binary files a/gscats.2mg and b/gscats.2mg differ
diff --git a/gscats.s b/gscats.s
index 4d35319..b786fbe 100644
--- a/gscats.s
+++ b/gscats.s
@@ -8,12 +8,15 @@
 .include "macros.s"
 .include "equates.s"
 
+.import renderTerrainSpans
+.import unrenderTerrainSpans
+.import compileTerrainSpans
+
 .org $0000
 
 
 mainBank2:
 	SYNCDBR
-
 	BITS8
 	lda #$f0
 	sta TEXTCOLOR
diff --git a/linkerConfig b/linkerConfig
new file mode 100644
index 0000000..4a1b127
--- /dev/null
+++ b/linkerConfig
@@ -0,0 +1,44 @@
+FEATURES {
+	STARTADDRESS: default = $0803;
+}
+
+MEMORY {
+	ZP:     start = $0080, size = $001A,                 define = yes;
+	HEADER: start = $0000, size = $0004,      file = %O;
+	RAM:    start = %S,    size = $9600 - %S, file = %O, define = yes;
+	MOVE:   start = $0000, size = $FFFF,      file = %O, define = yes;
+	LC:     start = $D400, size = $0C00,                 define = yes;
+}
+
+SEGMENTS {
+	ZEROPAGE: load = ZP,              type = zp;
+	EXEHDR:   load = HEADER,          type = ro;
+	STARTUP:  load = RAM,             type = ro;
+	LOWCODE:  load = RAM,             type = ro;
+	CODE:     load = RAM,             type = ro;
+	RODATA:   load = RAM,             type = ro;
+	DATA:     load = RAM,             type = rw;
+	ZPSAVE:   load = RAM,             type = bss, define   = yes;
+	BSS:      load = RAM,             type = bss, define   = yes;
+	INIT:     load = MOVE, run = RAM, type = ro,  define   = yes;
+	HIGHCODE: load = MOVE, run = LC,  type = ro,  optional = yes;
+}
+
+FEATURES {
+	CONDES: segment = INIT,
+	type    = constructor,
+	label   = __CONSTRUCTOR_TABLE__,
+	count   = __CONSTRUCTOR_COUNT__;
+	CONDES: segment = RODATA,
+	type    = destructor,
+	label   = __DESTRUCTOR_TABLE__,
+	count   = __DESTRUCTOR_COUNT__;
+	CONDES: type    = interruptor,
+	segment = RODATA,
+	label   = __INTERRUPTOR_TABLE__,
+	count   = __INTERRUPTOR_COUNT__;
+}
+SYMBOLS {
+	__STACKSIZE__: value = $0800, weak = yes;
+}
+
diff --git a/loader.s b/loader.s
index 07c3a13..865cd83 100644
--- a/loader.s
+++ b/loader.s
@@ -40,10 +40,42 @@ main:
 	; Copy code into bank 2
 	ldx fileReadLen
 	lda #2
+	ldy #0
 	jsr copyBytes
 
 	EMULATION
 
+;;;;;;;;;;;;;;;;;;;;;
+
+	; Open the E1 code file
+	jsr PRODOS
+	.byte $c8
+	.addr fileOpenCodeE1
+	bne ioError
+
+	; Load the code into bank 0
+	jsr PRODOS
+	.byte $ca
+	.addr fileRead
+	bne ioError
+
+	; Close the file
+	jsr PRODOS
+	.byte $cc
+	.addr fileClose
+
+	NATIVE
+
+	; Copy code into bank E1
+	ldx fileReadLen
+	lda #$E1
+	ldy #$800		; Must match terrain_e1 .org
+	jsr copyBytes
+
+	EMULATION
+
+;;;;;;;;;;;;;;;;;;;;;
+
 	; Open the sprite bank file
 	jsr PRODOS
 	.byte $c8
@@ -66,6 +98,7 @@ main:
 	; Copy sprites into bank 3
 	ldx fileReadLen
 	lda #3
+	ldy #0
 	jsr copyBytes
 
 	; Set up a long jump into bank 2, and
@@ -73,6 +106,7 @@ main:
 	; properly to ProDOS 8
 	lda #returnToProDOS
 	sta PRODOSRETURN
+
 	jml MAINENTRY
 
 returnToProDOS:
@@ -90,9 +124,13 @@ ioError:
 ; bottom of any other bank. Must be in native mode.
 ;
 ; X = Length of data in bytes
+; Y = Origin within bank
 ; A = Bank number of destination
 ;
 copyBytes:
+	sty copyBytesDest+1
+	sty copyBytesDest2+1
+
 	phx
 	BITS8
 	sta copyBytesDest+3
@@ -135,6 +173,13 @@ fileOpenCode:
 	.byte 0					; Result (file handle)
 	.byte 0					; Padding
 
+fileOpenCodeE1:
+	.byte 3
+	.addr codePathE1
+	.addr $9200				; 1k below BASIC.SYSTEM
+	.byte 0					; Result (file handle)
+	.byte 0					; Padding
+
 fileRead:
 	.byte 4
 	.byte 1					; File handle (we know it's gonna be 1)
@@ -156,5 +201,7 @@ fileOpenSprites:
 
 codePath:
 	pstring "/GSAPP/CODEBANK"
+codePathE1:
+	pstring "/GSAPP/CODEBANKE1"
 spritePath:
 	pstring "/GSAPP/SPRITEBANK00"
diff --git a/macros.s b/macros.s
index 8d77782..4bfb12a 100644
--- a/macros.s
+++ b/macros.s
@@ -42,6 +42,15 @@
 	plb
 .endmacro
 
+.macro SAVE_DBR
+	phb
+	phk
+	plb
+.endmacro
+
+.macro RESTORE_DBR
+	plb
+.endmacro
 
 .macro EMULATION
 	sec		; Enable 8-bit mode
diff --git a/tables.s b/tables.s
index 355aa6f..6f18ab2 100644
--- a/tables.s
+++ b/tables.s
@@ -152,16 +152,4 @@ vramYOffset:
 	.word $6400,$64a0,$6540,$65e0,$6680,$6720,$67c0,$6860,$6900,$69a0,$6a40,$6ae0,$6b80,$6c20,$6cc0,$6d60,$6e00,$6ea0,$6f40,$6fe0
 	.word $7080,$7120,$71c0,$7260,$7300,$73a0,$7440,$74e0,$7580,$7620,$76c0,$7760,$7800,$78a0,$7940,$79e0,$7a80,$7b20,$7bc0,$7c60
 
-vramRowInvertedSpanLookup:
-	.word $9d00,$9c60,$9bc0,$9b20,$9a80,$99e0,$9940,$98a0,$9800,$9760,$96c0,$9620,$9580,$94e0,$9440,$93a0,$9300,$9260,$91c0,$9120
-	.word $9080,$8fe0,$8f40,$8ea0,$8e00,$8d60,$8cc0,$8c20,$8b80,$8ae0,$8a40,$89a0,$8900,$8860,$87c0,$8720,$8680,$85e0,$8540,$84a0
-	.word $8400,$8360,$82c0,$8220,$8180,$80e0,$8040,$7fa0,$7f00,$7e60,$7dc0,$7d20,$7c80,$7be0,$7b40,$7aa0,$7a00,$7960,$78c0,$7820
-	.word $7780,$76e0,$7640,$75a0,$7500,$7460,$73c0,$7320,$7280,$71e0,$7140,$70a0,$7000,$6f60,$6ec0,$6e20,$6d80,$6ce0,$6c40,$6ba0
-	.word $6b00,$6a60,$69c0,$6920,$6880,$67e0,$6740,$66a0,$6600,$6560,$64c0,$6420,$6380,$62e0,$6240,$61a0,$6100,$6060,$5fc0,$5f20
-	.word $5e80,$5de0,$5d40,$5ca0,$5c00,$5b60,$5ac0,$5a20,$5980,$58e0,$5840,$57a0,$5700,$5660,$55c0,$5520,$5480,$53e0,$5340,$52a0
-	.word $5200,$5160,$50c0,$5020,$4f80,$4ee0,$4e40,$4da0,$4d00,$4c60,$4bc0,$4b20,$4a80,$49e0,$4940,$48a0,$4800,$4760,$46c0,$4620
-	.word $4580,$44e0,$4440,$43a0,$4300,$4260,$41c0,$4120,$4080,$3fe0,$3f40,$3ea0,$3e00,$3d60,$3cc0,$3c20,$3b80,$3ae0,$3a40,$39a0
-	.word $3900,$3860,$37c0,$3720,$3680,$35e0,$3540,$34a0,$3400,$3360,$32c0,$3220,$3180,$30e0,$3040,$2fa0,$2f00,$2e60,$2dc0,$2d20
-	.word $2c80,$2be0,$2b40,$2aa0,$2a00,$2960,$28c0,$2820,$2780,$26e0,$2640,$25a0,$2500,$2460,$23c0,$2320,$2280,$21e0,$2140,$20a0
-
 .include "circleTable.s"
diff --git a/terrain.s b/terrain.s
index 1b02058..525ab3a 100644
--- a/terrain.s
+++ b/terrain.s
@@ -4,16 +4,6 @@
 ;  Created by Quinn Dunki on 7/29/17
 ;
 
-
-TERRAINWIDTH = 640		; In pixels
-MAXTERRAINHEIGHT = 100	; In pixels
-COMPILEDTERRAINROW = TERRAINWIDTH/4+3	; In words, +2 to make room for clipping jump at end of row
-VISIBLETERRAINWIDTH = TERRAINWIDTH/4	; In words- width minus jump return padding
-VISIBLETERRAINWINDOW = 80				; In words
-MAXSPANSPERROW = 15
-SPANROWBYTES = MAXSPANSPERROW*2 + 2		; In bytes
-
-
 .if 0
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; renderTerrain
@@ -64,142 +54,6 @@ renderTerrainDone:
 	rts
 .endif
 
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; renderTerrainSpans:
-;
-;
-renderTerrainSpans:
-	SAVE_AXY
-	FASTGRAPHICS
-
-	lda #$800	; Prepare unrender cache
-	tcs
-
-	lda #terrainSpanWriteCache
-	sta CACHEPTR
-
-	lda #MAXTERRAINHEIGHT-1
-
-renderTerrainSpansLoop:
-	sta PARAML1
-
-	; Find row data
-	lda PARAML1
-	asl		; Shifts must match SPANROWBYTES
-	asl
-	asl
-	asl
-	asl
-	tay
-	lda terrainSpanData,y
-	sta SCRATCHL			; Track span color
-
-	; Find VRAM row
-	lda PARAML1
-	asl
-	tax
-	lda vramRowInvertedSpanLookup,x
-	tax
-	
-	adc #160
-	sta PARAML0				; Watch for end of VRAM row
-
-	; Find span that intersects left logical edge
-	lda #0
-	clc
-
-renderTerrainRowSpansFindLeftLoop:
-	adc terrainSpanData+2,y
-	cmp leftScreenEdge
-	bpl renderTerrainRowSpansFoundLeft
-	iny
-	iny
-	sta CACHEDATA
-	lda SCRATCHL
-	eor #%110000	; Toggle span color cache
-	sta SCRATCHL
-	lda CACHEDATA
-	bra renderTerrainRowSpansFindLeftLoop
-
-renderTerrainRowSpansFoundLeft:
-	sec
-	sbc leftScreenEdge	; A now holds remainder of leftmost span
-						; and Y points to leftmost span
-
-renderTerrainRowSpansLoop:
-	sta SCRATCHL2
-
-	; Set fill mode byte for this span
-	lda SCRATCHL
-	sta VRAMBANK,x
-
-	; Cache the index we wrote to so we can erase later
-	phx
-;	txa
-;	sta (CACHEPTR)
-;	inc CACHEPTR
-;	inc CACHEPTR
-
-	; Advance to end of span
-	clc
-	txa
-	adc SCRATCHL2
-	cmp PARAML0
-	bpl renderTerrainRowSpansDone
-	tax
-
-	; Prepare for next span
-	iny
-	iny
-	lda SCRATCHL
-	eor #%110000	; Toggle span color cache
-	sta SCRATCHL
-
-	lda terrainSpanData+2,y
-	bra renderTerrainRowSpansLoop
-
-renderTerrainRowSpansDone:
-	lda PARAML1
-	dec
-	bne renderTerrainSpansLoop
-
-	pea 0		; Null-terminate the unrender cache
-	SLOWGRAPHICS
-	RESTORE_AXY
-	rts
-
-
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; unrenderTerrainSpans:
-;
-;
-
-unrenderTerrainSpans:
-	SAVE_AXY
-	phb
-	pea $e1e1		; Work entirely in bank E1 for all local read/writes
-	plb
-	plb
-
-	ldy #$800-1
-
-unrenderTerrainSpansLoop:
-	lda 0,y
-	beq unrenderTerrainSpansDone
-	tax
-	lda #0
-	sta a:0,x
-	dey
-	dey
-	bra unrenderTerrainSpansLoop
-
-unrenderTerrainSpansDone:
-	plb
-	RESTORE_AXY
-	rts
-
-
 
 .if 0
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -618,123 +472,6 @@ compileTerrainOpcode:
 
 .endif
 
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; compileTerrainSpans:
-;
-;
-compileTerrainSpans:
-	pha
-	lda #0
-
-compileTerrainSpansLoop:
-	sta PARAML1
-	jsr compileTerrainSpansRow
-	lda PARAML1
-	inc
-	cmp #MAXTERRAINHEIGHT
-	bne compileTerrainSpansLoop
-
-	pla
-	rts
-
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; compileTerrainSpansRow:
-;
-; PARAML1 = Row index (bottom relative)
-;
-; Trashes SCRATCHL
-;
-compileTerrainSpansRow:
-	SAVE_AXY
-
-	lda PARAML1
-	asl		; Shifts must match SPANROWBYTES
-	asl
-	asl
-	asl
-	asl
-	clc
-	adc #terrainSpanData
-	sta SCRATCHL
-
-	ldy #0
-	ldx #TERRAINWIDTH-2
-
-	lda terrainData,x	; Figure out start value for row
-	cmp PARAML1
-	bcs compileTerrainSpansRowInitGreen
-
-compileTerrainSpansRowInitBlack:
-	lda #$0020		; First span is black
-	sta (SCRATCHL)	; Initialize the row
-	inc SCRATCHL
-	inc SCRATCHL
-	ldy #-1
-
-compileTerrainSpansRowBlackStart:
-	iny
-
-compileTerrainSpansRowBlackLoop:
-	lda terrainData,x
-	cmp PARAML1
-	bcs compileTerrainSpansBlackEnd
-	dex
-	dex
-	iny
-	cpx #-2
-	bne compileTerrainSpansRowBlackLoop
-
-compileTerrainSpansBlackEnd:
-	tya				; Store this span's length
-	sta (SCRATCHL)
-	inc SCRATCHL
-	inc SCRATCHL
-
-	dex				; Begin searching for next span
-	dex
-	cpx #0
-	bmi compileTerrainSpansRowDone
-	ldy #0
-	bra compileTerrainSpansRowGreenStart
-
-compileTerrainSpansRowDone:
-	RESTORE_AXY
-	rts
-
-compileTerrainSpansRowInitGreen:
-	lda #$0010		; First span is green
-	sta (SCRATCHL)	; Initialize the row
-	inc SCRATCHL
-	inc SCRATCHL
-	ldy #-1
-
-compileTerrainSpansRowGreenStart:
-	iny
-
-compileTerrainSpansRowGreenLoop:
-	lda terrainData,x
-	cmp PARAML1
-	bcc compileTerrainSpansGreenEnd
-	dex
-	dex
-	iny
-	cpx #-2
-	bne compileTerrainSpansRowGreenLoop
-
-compileTerrainSpansGreenEnd:
-	tya				; Store this span's length
-	sta (SCRATCHL)
-	inc SCRATCHL
-	inc SCRATCHL
-
-	dex				; Begin searching for next span
-	dex
-	cpx #0
-	bmi compileTerrainSpansRowDone
-	ldy #0
-	bra compileTerrainSpansRowBlackStart
-
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; prepareRowRendering:
@@ -820,15 +557,6 @@ generateTerrainLoop:
 	rts
 
 
-
-; Terrain data, stored as height values 2 pixels wide (bytes)
-
-terrainData:
-	.repeat TERRAINWIDTH/2
-	.word 0
-	.endrepeat
-terrainDataEnd:
-
 .if 0
 compiledTerrain:
 	.repeat COMPILEDTERRAINROW * MAXTERRAINHEIGHT
@@ -842,18 +570,3 @@ clippedTerrainData:
 	.endrepeat
 .endif
 
-terrainSpanData:
-	.repeat MAXTERRAINHEIGHT
-		.word 0		; Start value (0=BG)
-		.repeat MAXSPANSPERROW
-		.word 0		; Length (in bytes)
-		.endrepeat
-	.endrepeat
-
-terrainSpanWriteCacheNull:
-	.word 0	; Null terminator for when popping off LIFO
-terrainSpanWriteCache:
-	.repeat 512
-	.word 0			; LIFO for tracking span byte writes
-	.endrepeat
-
diff --git a/terrain_e1.s b/terrain_e1.s
new file mode 100644
index 0000000..728faa7
--- /dev/null
+++ b/terrain_e1.s
@@ -0,0 +1,304 @@
+;
+;  terrain (in E1 bank)
+;
+;  Fill-mode terrain rendering code snippets
+;  that live in bank E1 for maximum speed.
+;
+;  Created by Quinn Dunki on 7/29/17
+;
+
+.include "equates.s"
+.include "macros.s"
+
+UNRENDERCACHESTACK = $7ff
+
+OP16
+
+.org $800
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; renderTerrainSpans:
+;
+;
+renderTerrainSpans:
+	SAVE_AXY
+	SAVE_DBR
+	FASTGRAPHICS
+
+	lda #UNRENDERCACHESTACK	; Prepare unrender cache
+	tcs
+
+	lda #MAXTERRAINHEIGHT-1
+
+renderTerrainSpansLoop:
+	sta PARAML1
+
+	; Find row data
+	lda PARAML1
+	asl		; Shifts must match SPANROWBYTES
+	asl
+	asl
+	asl
+	asl
+	tay
+	lda terrainSpanData,y
+	sta SCRATCHL			; Track span color
+
+	; Find VRAM row
+	lda PARAML1
+	asl
+	tax
+	lda vramRowInvertedSpanLookup,x
+	tax
+	
+	adc #160
+	sta PARAML0				; Watch for end of VRAM row
+
+	; Find span that intersects left logical edge
+	lda #0
+	clc
+
+renderTerrainRowSpansFindLeftLoop:
+	adc terrainSpanData+2,y
+	cmp leftScreenEdge
+	bpl renderTerrainRowSpansFoundLeft
+	iny
+	iny
+	sta CACHEDATA
+	lda SCRATCHL
+	eor #%110000	; Toggle span color cache
+	sta SCRATCHL
+	lda CACHEDATA
+	bra renderTerrainRowSpansFindLeftLoop
+
+renderTerrainRowSpansFoundLeft:
+	sec
+	sbc leftScreenEdge	; A now holds remainder of leftmost span
+						; and Y points to leftmost span
+
+renderTerrainRowSpansLoop:
+	sta SCRATCHL2
+
+	; Set fill mode byte for this span
+	lda SCRATCHL
+	sta VRAMBANK,x
+
+	; Cache the index we wrote to so we can erase later
+	phx
+
+	; Advance to end of span
+	clc
+	txa
+	adc SCRATCHL2
+	cmp PARAML0
+	bpl renderTerrainRowSpansDone
+	tax
+
+	; Prepare for next span
+	iny
+	iny
+	lda SCRATCHL
+	eor #%110000	; Toggle span color cache
+	sta SCRATCHL
+
+	lda terrainSpanData+2,y
+	bra renderTerrainRowSpansLoop
+
+renderTerrainRowSpansDone:
+	lda PARAML1
+	dec
+	bne renderTerrainSpansLoop
+
+	pea 0		; Null-terminate the unrender cache
+	SLOWGRAPHICS
+	RESTORE_DBR
+	RESTORE_AXY
+	rtl
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; unrenderTerrainSpans:
+;
+;
+
+unrenderTerrainSpans:
+	SAVE_AXY
+	SAVE_DBR
+	phb
+	pea $e1e1		; Work entirely in bank E1 for all local read/writes
+	plb
+	plb
+
+	ldy #UNRENDERCACHESTACK-1
+
+unrenderTerrainSpansLoop:
+	lda 0,y
+	beq unrenderTerrainSpansDone
+	tax
+	lda #0
+	sta a:0,x
+	dey
+	dey
+	bra unrenderTerrainSpansLoop
+
+unrenderTerrainSpansDone:
+	plb
+	RESTORE_DBR
+	RESTORE_AXY
+	rtl
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; compileTerrainSpans:
+;
+;
+compileTerrainSpans:
+	pha
+	SAVE_DBR
+	lda #0
+
+compileTerrainSpansLoop:
+	sta PARAML1
+	jsr compileTerrainSpansRow
+	lda PARAML1
+	inc
+	cmp #MAXTERRAINHEIGHT
+	bne compileTerrainSpansLoop
+
+	RESTORE_DBR
+	pla
+	rtl
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; compileTerrainSpansRow:
+;
+; PARAML1 = Row index (bottom relative)
+;
+; Trashes SCRATCHL
+;
+compileTerrainSpansRow:
+	SAVE_AXY
+
+	lda PARAML1
+	asl		; Shifts must match SPANROWBYTES
+	asl
+	asl
+	asl
+	asl
+	clc
+	adc #terrainSpanData
+	sta SCRATCHL
+
+	ldy #0
+	ldx #TERRAINWIDTH-2
+
+	lda terrainDataFar,x	; Figure out start value for row
+	cmp PARAML1
+	bcs compileTerrainSpansRowInitGreen
+
+compileTerrainSpansRowInitBlack:
+	lda #$0020		; First span is black
+	sta (SCRATCHL)	; Initialize the row
+	inc SCRATCHL
+	inc SCRATCHL
+	ldy #-1
+
+compileTerrainSpansRowBlackStart:
+	iny
+
+compileTerrainSpansRowBlackLoop:
+	lda terrainDataFar,x
+	cmp PARAML1
+	bcs compileTerrainSpansBlackEnd
+	dex
+	dex
+	iny
+	cpx #-2
+	bne compileTerrainSpansRowBlackLoop
+
+compileTerrainSpansBlackEnd:
+	tya				; Store this span's length
+	sta (SCRATCHL)
+	inc SCRATCHL
+	inc SCRATCHL
+
+	dex				; Begin searching for next span
+	dex
+	cpx #0
+	bmi compileTerrainSpansRowDone
+	ldy #0
+	bra compileTerrainSpansRowGreenStart
+
+compileTerrainSpansRowDone:
+	RESTORE_AXY
+	rts
+
+compileTerrainSpansRowInitGreen:
+	lda #$0010		; First span is green
+	sta (SCRATCHL)	; Initialize the row
+	inc SCRATCHL
+	inc SCRATCHL
+	ldy #-1
+
+compileTerrainSpansRowGreenStart:
+	iny
+
+compileTerrainSpansRowGreenLoop:
+	lda terrainDataFar,x
+	cmp PARAML1
+	bcc compileTerrainSpansGreenEnd
+	dex
+	dex
+	iny
+	cpx #-2
+	bne compileTerrainSpansRowGreenLoop
+
+compileTerrainSpansGreenEnd:
+	tya				; Store this span's length
+	sta (SCRATCHL)
+	inc SCRATCHL
+	inc SCRATCHL
+
+	dex				; Begin searching for next span
+	dex
+	cpx #0
+	bmi compileTerrainSpansRowDone
+	ldy #0
+	bra compileTerrainSpansRowBlackStart
+
+terrainSpanData:
+	.repeat MAXTERRAINHEIGHT
+		.word 0		; Start value (0=BG)
+		.repeat MAXSPANSPERROW
+		.word 0		; Length (in bytes)
+		.endrepeat
+	.endrepeat
+
+
+vramRowInvertedSpanLookup:
+	.word $9d00,$9c60,$9bc0,$9b20,$9a80,$99e0,$9940,$98a0,$9800,$9760,$96c0,$9620,$9580,$94e0,$9440,$93a0,$9300,$9260,$91c0,$9120
+	.word $9080,$8fe0,$8f40,$8ea0,$8e00,$8d60,$8cc0,$8c20,$8b80,$8ae0,$8a40,$89a0,$8900,$8860,$87c0,$8720,$8680,$85e0,$8540,$84a0
+	.word $8400,$8360,$82c0,$8220,$8180,$80e0,$8040,$7fa0,$7f00,$7e60,$7dc0,$7d20,$7c80,$7be0,$7b40,$7aa0,$7a00,$7960,$78c0,$7820
+	.word $7780,$76e0,$7640,$75a0,$7500,$7460,$73c0,$7320,$7280,$71e0,$7140,$70a0,$7000,$6f60,$6ec0,$6e20,$6d80,$6ce0,$6c40,$6ba0
+	.word $6b00,$6a60,$69c0,$6920,$6880,$67e0,$6740,$66a0,$6600,$6560,$64c0,$6420,$6380,$62e0,$6240,$61a0,$6100,$6060,$5fc0,$5f20
+	.word $5e80,$5de0,$5d40,$5ca0,$5c00,$5b60,$5ac0,$5a20,$5980,$58e0,$5840,$57a0,$5700,$5660,$55c0,$5520,$5480,$53e0,$5340,$52a0
+	.word $5200,$5160,$50c0,$5020,$4f80,$4ee0,$4e40,$4da0,$4d00,$4c60,$4bc0,$4b20,$4a80,$49e0,$4940,$48a0,$4800,$4760,$46c0,$4620
+	.word $4580,$44e0,$4440,$43a0,$4300,$4260,$41c0,$4120,$4080,$3fe0,$3f40,$3ea0,$3e00,$3d60,$3cc0,$3c20,$3b80,$3ae0,$3a40,$39a0
+	.word $3900,$3860,$37c0,$3720,$3680,$35e0,$3540,$34a0,$3400,$3360,$32c0,$3220,$3180,$30e0,$3040,$2fa0,$2f00,$2e60,$2dc0,$2d20
+	.word $2c80,$2be0,$2b40,$2aa0,$2a00,$2960,$28c0,$2820,$2780,$26e0,$2640,$25a0,$2500,$2460,$23c0,$2320,$2280,$21e0,$2140,$20a0
+
+
+
+
+.export renderTerrainSpans
+.export unrenderTerrainSpans
+.export compileTerrainSpans
+
+
+; Suppress some linker warnings - Must be the last thing in the file
+.SEGMENT "ZPSAVE"
+.SEGMENT "EXEHDR"
+.SEGMENT "STARTUP"
+.SEGMENT "INIT"
+.SEGMENT "LOWCODE"