From c05084c2894978f83037b03fd1fe65bc2b335c74 Mon Sep 17 00:00:00 2001
From: Vince Weaver <vince@deater.net>
Date: Fri, 29 Dec 2023 13:47:18 -0500
Subject: [PATCH] gr-sim: uppercase the 6502 emulated registers

probably broke something, but this also was a pain as was
often accidentally using the vars, especially X and Y
---
 utils/gr-sim/6502_emulate.c        | 302 +++++++++---------
 utils/gr-sim/6502_emulate.h        |   6 +-
 utils/gr-sim/6502_test/6502_test.c |  64 ++--
 utils/gr-sim/Makefile              |  10 +
 utils/gr-sim/bubble/Makefile       |  13 +-
 utils/gr-sim/bubble/bubble_orig.c  |  65 ++++
 utils/gr-sim/dos/nibble.c          |  24 +-
 utils/gr-sim/dots/8086_emulator.c  |   2 +-
 utils/gr-sim/gr-sim.c              | 479 +++++++++++++++--------------
 utils/gr-sim/gr-sim.h              |   8 +-
 utils/gr-sim/hgr-sim.c             | 254 +++++++--------
 utils/gr-sim/hgr/Makefile          |  15 +-
 utils/gr-sim/hgr/fw_purple.c       |  20 +-
 utils/gr-sim/hgr/random16.c        |  18 +-
 utils/gr-sim/hgr/scroll-asm.c      |  48 +--
 utils/gr-sim/hgr/seven.c           |  26 +-
 utils/gr-sim/lz4/krw_decode.c      | 178 +++++------
 utils/gr-sim/lz4/lz4d_verbose.c    | 114 +++----
 utils/gr-sim/tfv/tfv_flying_6502.c |  12 +-
 utils/gr-sim/tfv_utils.c           |  14 +-
 utils/gr-sim/twister/Makefile      |   2 +-
 21 files changed, 889 insertions(+), 785 deletions(-)
 create mode 100644 utils/gr-sim/bubble/bubble_orig.c

diff --git a/utils/gr-sim/6502_emulate.c b/utils/gr-sim/6502_emulate.c
index 9751518f..601f55fa 100644
--- a/utils/gr-sim/6502_emulate.c
+++ b/utils/gr-sim/6502_emulate.c
@@ -9,21 +9,21 @@
 unsigned char ram[RAMSIZE];
 
 /* Registers */
-unsigned char a,y,x;
-unsigned short sp;
+unsigned char A,Y,X;
+unsigned short SP;
 
 /* Flags */
-unsigned int n,z,c,v;
+unsigned int N,Z,C,V;
 
 int init_6502(void) {
 
-	a=0;
-	y=0;
-	x=0;
+	A=0;
+	Y=0;
+	X=0;
 
-	sp=0x1ff;
+	SP=0x1ff;
 
-	n=0; z=0; c=0; v=0;
+	N=0; Z=0; C=0; V=0;
 
 	return 0;
 
@@ -42,7 +42,7 @@ unsigned short y_indirect(unsigned char base, unsigned char y) {
 }
 
 void clc(void) {
-	c=0;
+	C=0;
 }
 
 void adc(int value) {
@@ -51,18 +51,18 @@ void adc(int value) {
 	int temp_value;
 	int result;
 
-	temp_a=a&0xff;
+	temp_a=A&0xff;
 	temp_value=value&0xff;
 
-	result=(temp_a+temp_value+c);
+	result=(temp_a+temp_value+C);
 
-	c=(result&0x100)>>8;
-	n=(result&0x80)>>7;
+	C=(result&0x100)>>8;
+	N=(result&0x80)>>7;
 
-	v=!!((a^result)&(value^result)&0x80);
+	V=!!((A^result)&(value^result)&0x80);
 
-	a=result&0xff;
-	z=(a==0);
+	A=result&0xff;
+	Z=(A==0);
 
 }
 
@@ -72,18 +72,18 @@ void adc_mem(int addr) {
 	int temp_value;
 	int result;
 
-	temp_a=a&0xff;
+	temp_a=A&0xff;
 	temp_value=ram[addr]&0xff;
 
-	result=(temp_a+temp_value+c);
+	result=(temp_a+temp_value+C);
 
-	c=(result&0x100)>>8;
-	n=(result&0x80)>>7;
+	C=(result&0x100)>>8;
+	N=(result&0x80)>>7;
 
-	v=!!((a^result)&(temp_value^result)&0x80);
+	V=!!((A^result)&(temp_value^result)&0x80);
 
-	a=result&0xff;
-	z=(a==0);
+	A=result&0xff;
+	Z=(A==0);
 
 }
 
@@ -92,20 +92,20 @@ void sbc(int value) {
 	int result;
 	int temp_value;
 
-	temp_a=a&0xff;
+	temp_a=A&0xff;
 	temp_value=(~value)&0xff;
 
-	result=temp_a+temp_value+c;
+	result=temp_a+temp_value+C;
 
-//	printf("SBC: %x - %x (%x) = %x\n",a,value,c,result);
+//	printf("SBC: %x - %x (%x) = %x\n",A,value,C,result);
 
-	c=(result&0x100)>>8;
-	n=(result&0x80)>>7;
+	C=(result&0x100)>>8;
+	N=(result&0x80)>>7;
 
-	v=!!((a^result)&((255-value)^result)&0x80);
+	V=!!((A^result)&((255-value)^result)&0x80);
 
-	a=result&0xff;
-	z=(a==0);
+	A=result&0xff;
+	Z=(A==0);
 
 
 }
@@ -115,20 +115,20 @@ void sbc_mem(int addr) {
 	int result;
 	int temp_value;
 
-	temp_a=a&0xff;
+	temp_a=A&0xff;
 	temp_value=(~ram[addr])&0xff;
 
-	result=temp_a+temp_value+c;
+	result=temp_a+temp_value+C;
 
-//	printf("SBC: %x - %x (%x) = %x\n",a,value,c,result);
+//	printf("SBC: %x - %x (%x) = %x\n",A,value,C,result);
 
-	c=(result&0x100)>>8;
-	n=(result&0x80)>>7;
+	C=(result&0x100)>>8;
+	N=(result&0x80)>>7;
 
-	v=!!((a^result)&((255-ram[addr])^result)&0x80);
+	V=!!((A^result)&((255-ram[addr])^result)&0x80);
 
-	a=result&0xff;
-	z=(a==0);
+	A=result&0xff;
+	Z=(A==0);
 
 
 }
@@ -139,17 +139,17 @@ void cmp(int value) {
 	int temp_value;
 	int result;
 
-	temp_a=a&0xff;
+	temp_a=A&0xff;
 	temp_value=(~value)&0xff;
 
 	result=temp_a+temp_value+1;
 
-	c=(result&0x100)>>8;
+	C=(result&0x100)>>8;
 
 	result&=0xff;
 
-	n=(result&0x80)>>7;
-	z=(result==0);
+	N=(result&0x80)>>7;
+	Z=(result==0);
 }
 
 void cpy(int value) {
@@ -158,17 +158,17 @@ void cpy(int value) {
 	int temp_value;
 	int result;
 
-	temp_y=y&0xff;
+	temp_y=Y&0xff;
 	temp_value=(~value)&0xff;
 
 	result=temp_y+temp_value+1;
 
-	c=(result&0x100)>>8;
+	C=(result&0x100)>>8;
 
 	result&=0xff;
 
-	n=(result&0x80)>>7;
-	z=(result==0);
+	N=(result&0x80)>>7;
+	Z=(result==0);
 }
 
 void cpx(int value) {
@@ -177,59 +177,59 @@ void cpx(int value) {
 	int temp_value;
 	int result;
 
-	temp_x=x&0xff;
+	temp_x=X&0xff;
 	temp_value=(~value)&0xff;
 
 	result=temp_x+temp_value+1;
 
-	c=(result&0x100)>>8;
+	C=(result&0x100)>>8;
 
 	result&=0xff;
 
-	n=(result&0x80)>>7;
-	z=(result==0);
+	N=(result&0x80)>>7;
+	Z=(result==0);
 }
 
 
 void pha(void) {
 
-	sp--;
-	ram[sp]=a;
+	SP--;
+	ram[SP]=A;
 }
 
 void pla(void) {
 
-	a=ram[sp];
-	sp++;
+	A=ram[SP];
+	SP++;
 }
 
 void lsr(void) {
 	int temp_a;
 
-	temp_a=a;
+	temp_a=A;
 	temp_a&=0xff;
 
-	c=temp_a&0x1;
+	C=temp_a&0x1;
 	temp_a=temp_a>>1;
-	a=(temp_a&0x7f);	// always shift 0 into top
-	z=(a==0);
-	n=!!(a&0x80);		// can this ever be 1?  no?
-//	printf("LSR A=%x\n",a);
+	A=(temp_a&0x7f);	// always shift 0 into top
+	Z=(A==0);
+	N=!!(A&0x80);		// can this ever be 1?  no?
+//	printf("LSR A=%x\n",A);
 }
 
 void asl(void) {
 	int temp_a;
 
-	temp_a=a;
+	temp_a=A;
 	temp_a&=0xff;
 
-	c=!!(temp_a&0x80);
+	C=!!(temp_a&0x80);
 
 	temp_a=temp_a<<1;
-	a=(temp_a&0xff);
-	z=(a==0);
-	n=!!(a&0x80);
-//	printf("ASL A=%x\n",a);
+	A=(temp_a&0xff);
+	Z=(A==0);
+	N=!!(A&0x80);
+//	printf("ASL A=%x\n",A);
 }
 
 void asl_mem(int addr) {
@@ -238,12 +238,12 @@ void asl_mem(int addr) {
 	temp_a=ram[addr];
 	temp_a&=0xff;
 
-	c=!!(temp_a&0x80);
+	C=!!(temp_a&0x80);
 
 	temp_a=temp_a<<1;
 	ram[addr]=(temp_a&0xff);
-	z=(ram[addr]==0);
-	n=!!(ram[addr]&0x80);
+	Z=(ram[addr]==0);
+	N=!!(ram[addr]&0x80);
 //	printf("ASL %x=%x\n",addr,ram[addr]);
 }
 
@@ -252,37 +252,37 @@ void ror(void) {
 	int temp_a;
 	int old_c;
 
-	old_c=c;
-	temp_a=a;
+	old_c=C;
+	temp_a=A;
 	temp_a&=0xff;
 
-	c=temp_a&0x1;
+	C=temp_a&0x1;
 	temp_a=temp_a>>1;
-	a=(temp_a&0xff);
-	a|=old_c<<7;
+	A=(temp_a&0xff);
+	A|=old_c<<7;
 
-	z=(a==0);
-	n=!!(a&0x80);
-//	printf("ROR A=%x\n",a);
+	Z=(A==0);
+	N=!!(A&0x80);
+//	printf("ROR A=%x\n",A);
 }
 
 void rol(void) {
 	int temp_a;
 	int old_c;
 
-	old_c=c;
-	temp_a=a;
+	old_c=C;
+	temp_a=A;
 	temp_a&=0xff;
 
-	c=!!(temp_a&0x80);
+	C=!!(temp_a&0x80);
 
 	temp_a=temp_a<<1;
-	a=(temp_a&0xff);
-	a|=old_c;
+	A=(temp_a&0xff);
+	A|=old_c;
 
-	z=(a==0);
-	n=!!(a&0x80);
-//	printf("ROL A=%x\n",a);
+	Z=(A==0);
+	N=!!(A&0x80);
+//	printf("ROL A=%x\n",A);
 }
 
 
@@ -291,17 +291,17 @@ void ror_mem(int addr) {
 	int temp_a;
 	int old_c;
 
-	old_c=c;
+	old_c=C;
 	temp_a=ram[addr];
 	temp_a&=0xff;
 
-	c=temp_a&0x1;
+	C=temp_a&0x1;
 	temp_a=temp_a>>1;
 	ram[addr]=(temp_a&0xff);
 	ram[addr]|=old_c<<7;
 
-	z=(ram[addr]==0);
-	n=!!(ram[addr]&0x80);
+	Z=(ram[addr]==0);
+	N=!!(ram[addr]&0x80);
 //	printf("ROR %x=%x\n",addr,ram[addr]);
 }
 
@@ -309,60 +309,60 @@ void rol_mem(int addr) {
 	int temp_a;
 	int old_c;
 
-	old_c=c;
+	old_c=C;
 	temp_a=ram[addr];
 	temp_a&=0xff;
 
-	c=!!(temp_a&0x80);
+	C=!!(temp_a&0x80);
 
 	temp_a=temp_a<<1;
 	ram[addr]=(temp_a&0xff);
 	ram[addr]|=old_c;
 
-	z=(ram[addr]==0);
-	n=!!(ram[addr]&0x80);
+	Z=(ram[addr]==0);
+	N=!!(ram[addr]&0x80);
 //	printf("ROL %x=%x\n",addr,ram[addr]);
 }
 
 
 void dex(void) {
-	x--;
+	X--;
 
-	z=(x==0);
-	n=!!(x&0x80);
+	Z=(X==0);
+	N=!!(X&0x80);
 }
 
 void dey(void) {
-	y--;
+	Y--;
 
-	z=(y==0);
-	n=!!(y&0x80);
+	Z=(Y==0);
+	N=!!(Y&0x80);
 }
 
 void inx(void) {
-	x++;
+	X++;
 
-	z=(x==0);
-	n=!!(x&0x80);
+	Z=(X==0);
+	N=!!(X&0x80);
 }
 
 void iny(void) {
-	y++;
+	Y++;
 
-	z=(y==0);
-	n=!!(y&0x80);
+	Z=(Y==0);
+	N=!!(Y&0x80);
 }
 
 void bit(int value) {
 	int temp_a;
 
-	temp_a=a&value;
+	temp_a=A&value;
 	temp_a&=0xff;
 
-	z=(temp_a==0);
+	Z=(temp_a==0);
 
-	n=(value&0x80);
-	v=(value&0x40);
+	N=(value&0x80);
+	V=(value&0x40);
 
 }
 
@@ -370,76 +370,76 @@ void bit(int value) {
 void bit_mem(int addr) {
 	int temp_a;
 
-	temp_a=a&ram[addr];
+	temp_a=A&ram[addr];
 	temp_a&=0xff;
 
-	z=(temp_a==0);
+	Z=(temp_a==0);
 
-	n=(ram[addr]&0x80);
-	v=(ram[addr]&0x40);
+	N=(ram[addr]&0x80);
+	V=(ram[addr]&0x40);
 
 }
 
 
 void lda(int addr) {
 
-	a=ram[addr];
+	A=ram[addr];
 
-	z=(a==0);
-	n=!!(a&0x80);
+	Z=(A==0);
+	N=!!(A&0x80);
 }
 
 void lda_const(int value) {
 
-	a=value;
+	A=value;
 
-	z=(a==0);
-	n=!!(a&0x80);
+	Z=(A==0);
+	N=!!(A&0x80);
 }
 
 void ldx(int addr) {
 
-	x=ram[addr];
+	X=ram[addr];
 
-	z=(x==0);
-	n=!!(x&0x80);
+	Z=(X==0);
+	N=!!(X&0x80);
 }
 
 void ldx_const(int value) {
 
-	x=value;
+	X=value;
 
-	z=(x==0);
-	n=!!(x&0x80);
+	Z=(X==0);
+	N=!!(X&0x80);
 }
 
 void ldy(int addr) {
 
-	y=ram[addr];
+	Y=ram[addr];
 
-	z=(y==0);
-	n=!!(y&0x80);
+	Z=(Y==0);
+	N=!!(Y&0x80);
 }
 
 void ldy_const(int value) {
 
-	y=value;
+	Y=value;
 
-	z=(y==0);
-	n=!!(y&0x80);
+	Z=(Y==0);
+	N=!!(Y&0x80);
 }
 
 void sta(int addr) {
 
-	ram[addr]=a;
+	ram[addr]=A;
 }
 
 void tax(void) {
-	x=a;
+	X=A;
 }
 
 void txa(void) {
-	a=x;
+	A=X;
 }
 
 void eor(int value) {
@@ -448,15 +448,15 @@ void eor(int value) {
 	int temp_value;
 	int result;
 
-	temp_a=a&0xff;
+	temp_a=A&0xff;
 	temp_value=value&0xff;
 
 	result=(temp_a^temp_value);
 
-	n=(result&0x80)>>7;
+	N=(result&0x80)>>7;
 
-	a=result&0xff;
-	z=(a==0);
+	A=result&0xff;
+	Z=(A==0);
 
 }
 
@@ -466,15 +466,15 @@ void ora(int value) {
 	int temp_value;
 	int result;
 
-	temp_a=a&0xff;
+	temp_a=A&0xff;
 	temp_value=value&0xff;
 
 	result=(temp_a|temp_value);
 
-	n=(result&0x80)>>7;
+	N=(result&0x80)>>7;
 
-	a=result&0xff;
-	z=(a==0);
+	A=result&0xff;
+	Z=(A==0);
 
 }
 
@@ -484,15 +484,15 @@ void ora_mem(int addr) {
 	int temp_value;
 	int result;
 
-	temp_a=a&0xff;
+	temp_a=A&0xff;
 	temp_value=ram[addr]&0xff;
 
 	result=(temp_a|temp_value);
 
-	n=(result&0x80)>>7;
+	N=(result&0x80)>>7;
 
-	a=result&0xff;
-	z=(a==0);
+	A=result&0xff;
+	Z=(A==0);
 
 }
 
@@ -502,15 +502,15 @@ void and(int value) {
 	int temp_value;
 	int result;
 
-	temp_a=a&0xff;
+	temp_a=A&0xff;
 	temp_value=value&0xff;
 
 	result=(temp_a&temp_value);
 
-	n=(result&0x80)>>7;
+	N=(result&0x80)>>7;
 
-	a=result&0xff;
-	z=(a==0);
+	A=result&0xff;
+	Z=(A==0);
 
 }
 
diff --git a/utils/gr-sim/6502_emulate.h b/utils/gr-sim/6502_emulate.h
index 24df07dd..a7b5d466 100644
--- a/utils/gr-sim/6502_emulate.h
+++ b/utils/gr-sim/6502_emulate.h
@@ -1,8 +1,8 @@
 #define RAMSIZE	128*1024
 extern unsigned char ram[RAMSIZE];
-extern unsigned char a,y,x;
-extern unsigned short sp;
-extern unsigned int n,z,c,v;
+extern unsigned char A,Y,X;
+extern unsigned short SP;
+extern unsigned int N,Z,C,V;
 
 unsigned short y_indirect(unsigned char base, unsigned char y);
 int init_6502(void);
diff --git a/utils/gr-sim/6502_test/6502_test.c b/utils/gr-sim/6502_test/6502_test.c
index d0aa0262..acffdba1 100644
--- a/utils/gr-sim/6502_test/6502_test.c
+++ b/utils/gr-sim/6502_test/6502_test.c
@@ -9,17 +9,17 @@ static void test_adc(void) {
 	/* carry in 0 */
 	for(i=0;i<256;i++) {
 		for(j=0;j<256;j++) {
-			c=0;
-			a=i;
+			C=0;
+			A=i;
 			adc(j);
-			if (a!=((i+j)&0xff)) {
-				printf("ADC: Error!  %d+%d should be %d, not %d\n",i,j,i+j,a);
+			if (A!=((i+j)&0xff)) {
+				printf("ADC: Error!  %d+%d should be %d, not %d\n",i,j,i+j,A);
 			}
-			if (c!=(((i+j)>>8)&0x1)) {
-				printf("ADC: Error!  Carry should be %d, not %d\n",((i+j)>>8)&0x1,c);
+			if (C!=(((i+j)>>8)&0x1)) {
+				printf("ADC: Error!  Carry should be %d, not %d\n",((i+j)>>8)&0x1,C);
 			}
-			if ((a==0) && (z!=1)) printf("ADC error, zflag wrong\n");
-			if ((a!=0) && (z!=0)) printf("ADC error, zflag wrong\n");
+			if ((A==0) && (Z!=1)) printf("ADC error, zflag wrong\n");
+			if ((A!=0) && (Z!=0)) printf("ADC error, zflag wrong\n");
 
 		}
 	}
@@ -27,17 +27,17 @@ static void test_adc(void) {
 	/* carry in 1 */
 	for(i=0;i<256;i++) {
 		for(j=0;j<256;j++) {
-			c=1;
-			a=i;
+			C=1;
+			A=i;
 			adc(j);
-			if (a!=((i+j+1)&0xff)) {
-				printf("ADC: Error!  %d+%d should be %d, not %d\n",i,j,i+j+1,a);
+			if (A!=((i+j+1)&0xff)) {
+				printf("ADC: Error!  %d+%d should be %d, not %d\n",i,j,i+j+1,A);
 			}
-			if (c!=(((i+j+1)>>8)&0x1)) {
-				printf("ADC: Error!  Carry should be %d, not %d\n",((i+j+1)>>8)&0x1,c);
+			if (C!=(((i+j+1)>>8)&0x1)) {
+				printf("ADC: Error!  Carry should be %d, not %d\n",((i+j+1)>>8)&0x1,C);
 			}
-			if ((a==0) && (z!=1)) printf("ADC error, zflag wrong\n");
-			if ((a!=0) && (z!=0)) printf("ADC error, zflag wrong\n");
+			if ((A==0) && (Z!=1)) printf("ADC error, zflag wrong\n");
+			if ((A!=0) && (Z!=0)) printf("ADC error, zflag wrong\n");
 		}
 	}
 }
@@ -48,34 +48,34 @@ static void test_sbc(void) {
 	/* carry in 1 */
 	for(i=0;i<256;i++) {
 		for(j=0;j<256;j++) {
-			c=1;
-			a=i;
+			C=1;
+			A=i;
 			sbc(j);
-			if (a!=((i-j-0)&0xff)) {
-				printf("SBC: Error!  %d-%d should be %d, not %d\n",i,j,i-j-0,a);
+			if (A!=((i-j-0)&0xff)) {
+				printf("SBC: Error!  %d-%d should be %d, not %d\n",i,j,i-j-0,A);
 			}
-			if (c==(((i-j-0)>>8)&0x1)) {
-				printf("SBC: Error!  Carry should be %d, not %d\n",((i-j-0)>>8)&0x1,c);
+			if (C==(((i-j-0)>>8)&0x1)) {
+				printf("SBC: Error!  Carry should be %d, not %d\n",((i-j-0)>>8)&0x1,C);
 			}
-			if ((a==0) && (z!=1)) printf("SBC error, zflag wrong\n");
-			if ((a!=0) && (z!=0)) printf("SBC error, zflag wrong\n");
+			if ((A==0) && (Z!=1)) printf("SBC error, zflag wrong\n");
+			if ((A!=0) && (Z!=0)) printf("SBC error, zflag wrong\n");
 		}
 	}
 
 	/* carry in 0 */
 	for(i=0;i<256;i++) {
 		for(j=0;j<256;j++) {
-			c=0;
-			a=i;
+			C=0;
+			A=i;
 			sbc(j);
-			if (a!=((i-j-1)&0xff)) {
-				printf("SBC: Error!  %d-%d should be %d, not %d\n",i,j,i-j-1,a);
+			if (A!=((i-j-1)&0xff)) {
+				printf("SBC: Error!  %d-%d should be %d, not %d\n",i,j,i-j-1,A);
 			}
-			if (c==(((i-j-1)>>8)&0x1)) {
-				printf("SBC: Error!  Carry should be %d, not %d\n",((i-j-1)>>8)&0x1,c);
+			if (C==(((i-j-1)>>8)&0x1)) {
+				printf("SBC: Error!  Carry should be %d, not %d\n",((i-j-1)>>8)&0x1,C);
 			}
-			if ((a==0) && (z!=1)) printf("SBC error, zflag wrong\n");
-			if ((a!=0) && (z!=0)) printf("SBC error, zflag wrong\n");
+			if ((A==0) && (Z!=1)) printf("SBC error, zflag wrong\n");
+			if ((A!=0) && (Z!=0)) printf("SBC error, zflag wrong\n");
 		}
 	}
 
diff --git a/utils/gr-sim/Makefile b/utils/gr-sim/Makefile
index bea57146..764208f3 100644
--- a/utils/gr-sim/Makefile
+++ b/utils/gr-sim/Makefile
@@ -8,7 +8,10 @@ SDL_INCLUDE= `sdl-config --cflags`
 
 all:	gr-sim.a
 	make -C 6502_test
+	make -C bubble
+	make -C donut
 	make -C dos
+	make -C dots
 	make -C drops
 	make -C fade
 	make -C fire
@@ -21,12 +24,14 @@ all:	gr-sim.a
 	make -C mode7_demo
 	make -C plasma
 	make -C rasterbars
+	make -C raytrace
 	make -C rotate_wipe
 	make -C split_screen
 	make -C starfield
 	make -C text
 	make -C tfv
 	make -C tunnel
+	make -C twister
 	make -C water
 
 #### Library
@@ -58,7 +63,10 @@ hgr-sim.o:	hgr-sim.c gr-sim.h
 clean:	
 	rm -f *~ *.o *.a
 	make -C 6502_test clean
+	make -C bubble clean
+	make -C donut clean
 	make -C dos clean
+	make -C dots clean
 	make -C drops clean
 	make -C fade clean
 	make -C fire clean
@@ -71,10 +79,12 @@ clean:
 	make -C mode7_demo clean
 	make -C plasma clean
 	make -C rasterbars clean
+	make -C raytrace clean
 	make -C rotate_wipe clean
 	make -C split_screen clean
 	make -C starfield clean
 	make -C text clean
 	make -C tfv clean
 	make -C tunnel clean
+	make -C twister clean
 	make -C water clean
diff --git a/utils/gr-sim/bubble/Makefile b/utils/gr-sim/bubble/Makefile
index 1a27db4c..f06db1c4 100644
--- a/utils/gr-sim/bubble/Makefile
+++ b/utils/gr-sim/bubble/Makefile
@@ -6,7 +6,7 @@ SDL_LIBS= `sdl-config --libs`
 SDL_INCLUDE= `sdl-config --cflags`
 GR_SIM = ../gr-sim.a
 
-all:	bubble
+all:	bubble bubble_orig
 
 ####
 
@@ -18,5 +18,14 @@ bubble.o:	bubble.c
 
 ####
 
+bubble_orig:	bubble_orig.o $(GR_SIM)
+	$(CC) -o bubble_orig bubble_orig.o $(GR_SIM) $(SDL_LIBS) $(LFLAGS)
+
+bubble_orig.o:	bubble_orig.c
+	$(CC) $(CFLAGS) -c bubble_orig.c
+
+
+####
+
 clean:	
-	rm -f *~ *.o bubble
+	rm -f *~ *.o bubble bubble_orig
diff --git a/utils/gr-sim/bubble/bubble_orig.c b/utils/gr-sim/bubble/bubble_orig.c
new file mode 100644
index 00000000..af6cc872
--- /dev/null
+++ b/utils/gr-sim/bubble/bubble_orig.c
@@ -0,0 +1,65 @@
+/* Bubble */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include "gr-sim.h"
+#include "tfv_utils.h"
+#include "tfv_zp.h"
+
+
+int main(int argc, char **argv) {
+
+	int ch;
+	int n,i,j;
+	double r,rr,t,xx=0,u=0,v=0;//,sz,sw,sh;
+
+	grsim_init();
+
+	printf("XX=%lf\n",xx);
+
+	// HCOLOR=7
+	hcolor_equals(7);
+
+	// N=200:R=6.28/235:T=0:SZ=200:SW=280/SZ:SH=SCRH/SZ
+	n=32;	r=6.28/235.0;
+	t=0;
+
+	// HGR2:FOR I=0 TO N:RR=R*I:FOR J=0 TO N
+
+	hgr();
+	soft_switch(MIXCLR);
+	while(1) {
+		hclr();
+
+		clear_screens();
+		for(i=0;i<n;i++) {
+			rr=r*i;
+			for(j=0;j<n;j++) {
+				//U=SIN(I+V)+SIN(RR+X)
+				u=sin(i+v)+sin(rr+xx);
+				//V=COS(I+V)+COS(RR+X)
+				v=cos(i+v)+cos(rr+xx);
+				// X=U+T
+				xx=u+t;
+				//HPLOT 32*U+140,32*V+96
+				hplot(48*u+140,48*v+96);
+			}
+
+
+		}
+			grsim_update();
+			usleep(100000);
+
+			ch=grsim_input();
+			if (ch=='q') exit(0);
+		t=t+.025;
+
+	}
+
+	return 0;
+}
diff --git a/utils/gr-sim/dos/nibble.c b/utils/gr-sim/dos/nibble.c
index 22645129..a80bafa5 100644
--- a/utils/gr-sim/dos/nibble.c
+++ b/utils/gr-sim/dos/nibble.c
@@ -20,28 +20,28 @@ int main(int argc, char **argv) {
 	yy=0;
 	printf("****yy=%d\n",yy);
 
-	y=yy;			// ldy	   #0
-	x=3;			// ldx     #3
+	Y=yy;			// ldy	   #0
+	X=3;			// ldx     #3
 L1:
-	ram[0x3c]=x;		// stx     $3c
-	a=x;			// txa
+	ram[0x3c]=X;		// stx     $3c
+	A=X;			// txa
 	asl();			// asl
 	bit_mem(0x3c);		// bit     $3c
-	if (z==1) goto L3;	// beq     L3
+	if (Z==1) goto L3;	// beq     L3
 	ora_mem(0x3c);		// ora     $3c
 	eor(0xff);		// eor     #$ff
 	and(0x7e);		// and     #$7e
 L2:
-	if (c==1) goto L3;	// bcs     L3
+	if (C==1) goto L3;	// bcs     L3
 	lsr();			// lsr
-	if (z==0) goto L2;	// bne     L2
+	if (Z==0) goto L2;	// bne     L2
 
-	a=y;			// tya
-	printf("%x=%x\n",x,a);	// sta     nibtbl, x
-	y++;			// iny
+	A=Y;			// tya
+	printf("%x=%x\n",X,A);	// sta     nibtbl, x
+	Y++;			// iny
 L3:
-	x++;			// inx
-	if (!(x&0x80)) goto L1;	// bpl     L1
+	X++;			// inx
+	if (!(X&0x80)) goto L1;	// bpl     L1
 
 
 
diff --git a/utils/gr-sim/dots/8086_emulator.c b/utils/gr-sim/dots/8086_emulator.c
index 4df1aa78..d1d56486 100644
--- a/utils/gr-sim/dots/8086_emulator.c
+++ b/utils/gr-sim/dots/8086_emulator.c
@@ -4,7 +4,7 @@
 #include "8086_emulator.h"
 
 unsigned short stack[4096];
-unsigned short ax,bx,cx,dx,si,di,bp,cs,ds,es,fs;
+unsigned short ax,bx,cx,dx,si,di,bp,cs,ds,es,fs,sp;
 int cf=0,of=0,zf=0,sf=0;
 //int sp=0;
 
diff --git a/utils/gr-sim/gr-sim.c b/utils/gr-sim/gr-sim.c
index ba40d515..b5f7f25a 100644
--- a/utils/gr-sim/gr-sim.c
+++ b/utils/gr-sim/gr-sim.c
@@ -535,8 +535,8 @@ int grsim_update(void) {
 
 void setnorm(void) {
 
-	y=0xff;
-	ram[INVFLG]=y;
+	Y=0xff;
+	ram[INVFLG]=Y;
 
 }
 
@@ -576,7 +576,7 @@ int grsim_init(void) {
 	ram[WNDTOP]=0x00;
 	ram[WNDBTM]=0x18;
 
-	a=0; y=0; x=0;
+	A=0; Y=0; X=0;
 
 	//FA62 RESET
 
@@ -601,9 +601,9 @@ static void monitor_plot(void) {
 
 	/* Call into Monitor $F800 */
 
-	c=a&1;	/* save LSB in carry	*/
-	a=a>>1;	/* lsr A */
-	gbascalc(a);
+	c=A&1;	/* save LSB in carry	*/
+	A=A>>1;	/* lsr A */
+	gbascalc(A);
 
 	if (c) {
 		/* If odd, mask is 0xf0 */
@@ -614,15 +614,15 @@ static void monitor_plot(void) {
 		ram[MASK]=0x0f;
 	}
 
-	a=ram[y_indirect(GBASL,y)];
+	A=ram[y_indirect(GBASL,Y)];
 
-	a=a^ram[COLOR];
+	A=A^ram[COLOR];
 
-	a=a&ram[MASK];
+	A=A&ram[MASK];
 
-	a=a^ram[y_indirect(GBASL,y)];
+	A=A^ram[y_indirect(GBASL,Y)];
 
-	ram[y_indirect(GBASL,y)]=a;
+	ram[y_indirect(GBASL,Y)]=A;
 
 }
 
@@ -639,11 +639,11 @@ int basic_plot(unsigned char xcoord, unsigned char ycoord) {
 	/* Y-coord in A			*/
 	/* X-coord in Y			*/
 	/* Check that X-coord<40	*/
-	a=ycoord;
-	y=xcoord;
+	A=ycoord;
+	Y=xcoord;
 
-	if (y>=40) {
-		printf("X too big %d\n",y);
+	if (Y>=40) {
+		printf("X too big %d\n",Y);
 		return -1;
 	}
 
@@ -668,23 +668,23 @@ static void bascalc(void) {
 
 	unsigned char s,c;
 
-	s=a;
-	c=a&0x1;
+	s=A;
+	c=A&0x1;
 
-	a=a>>1;
-	a=a&0x3;
-	a=a|0x4;
-	ram[BASH]=a;
-	a=s;
-	a=a&0x18;
+	A=A>>1;
+	A=A&0x3;
+	A=A|0x4;
+	ram[BASH]=A;
+	A=s;
+	A=A&0x18;
 	if (c!=0) {
-		a=a+0x80;
+		A=A+0x80;
 	}
 // BSCLC2
-	ram[BASL]=a;
-	a=a<<2;
-	a=a|ram[BASL];
-	ram[BASL]=a;
+	ram[BASL]=A;
+	A=A<<2;
+	A=A|ram[BASL];
+	ram[BASL]=A;
 
 }
 
@@ -692,29 +692,29 @@ static void vtabz(void) {
 
 	bascalc();
 
-	a+=ram[WNDLFT];
-	ram[BASL]=a;
+	A+=ram[WNDLFT];
+	ram[BASL]=A;
 
 }
 
 static void rom_vtab(void) {
 	/* fb5b */
-	a=ram[CV];
+	A=ram[CV];
 	vtabz();
 }
 
 static void setwnd(void) {
 
-	ram[WNDTOP]=a;
-	a=0x0;
-	ram[WNDLFT]=a;
-	a=0x28;
-	ram[WNDWDTH]=a;
-	a=0x18;
-	ram[WNDBTM]=a;
-	a=0x17;
+	ram[WNDTOP]=A;
+	A=0x0;
+	ram[WNDLFT]=A;
+	A=0x28;
+	ram[WNDWDTH]=A;
+	A=0x18;
+	ram[WNDBTM]=A;
+	A=0x17;
 // TABV
-	ram[CV]=a;
+	ram[CV]=A;
 	rom_vtab();
 }
 
@@ -724,11 +724,11 @@ static void vline(void) {
 
 	// f828
 vline_loop:
-	s=a;
+	s=A;
 	monitor_plot();
-	a=s;
-	if (a<ram[V2]) {
-		a++;
+	A=s;
+	if (A<ram[V2]) {
+		A++;
 		goto vline_loop;
 	}
 }
@@ -736,15 +736,15 @@ vline_loop:
 static void clrtop(void) {
 
 	// f836
-	y=0x27;
-	ram[V2]=y;
-	y=0x27;
+	Y=0x27;
+	ram[V2]=Y;
+	Y=0x27;
 clrsc3:
-	a=0x0;
-	ram[COLOR]=a;
+	A=0x0;
+	ram[COLOR]=A;
 	vline();
-	y--;
-	if (y<=0x80) goto clrsc3;
+	Y--;
+	if (Y<=0x80) goto clrsc3;
 }
 
 static void setgr(void) {
@@ -756,7 +756,7 @@ static void setgr(void) {
 
 	clrtop();
 
-	a=0x14;
+	A=0x14;
 	setwnd();
 
 }
@@ -807,12 +807,12 @@ int bload(char *filename, int address) {
 static int cleolz(void) {
 	// FC9E
 
-	a=0xa0;
+	A=0xa0;
 clreol2:
-	ram[y_indirect(BASL,y)]=a;
-	y++;
+	ram[y_indirect(BASL,Y)]=A;
+	Y++;
 
-	if (y<ram[WNDWDTH]) goto clreol2;
+	if (Y<ram[WNDWDTH]) goto clreol2;
 
 	return 0;
 }
@@ -822,13 +822,13 @@ static int cleop1(void) {
 	unsigned char s;
 
 cleop1_begin:
-	s=a;
+	s=A;
 	vtabz();
 	cleolz();
-	y=0x00;
-	a=s;
-	a++;
-	if (a<=ram[WNDBTM]) goto cleop1_begin;
+	Y=0x00;
+	A=s;
+	A++;
+	if (A<=ram[WNDBTM]) goto cleop1_begin;
 	rom_vtab();
 
 	return 0;
@@ -837,10 +837,10 @@ cleop1_begin:
 int home(void) {
 
 	/* FC58 */
-	a=ram[WNDTOP];
-	ram[CV]=a;
-	y=0x00;
-	ram[CH]=y;
+	A=ram[WNDTOP];
+	ram[CV]=A;
+	Y=0x00;
+	ram[CH]=Y;
 	cleop1();
 
 	return 0;
@@ -853,8 +853,8 @@ int grsim_unrle_original(unsigned char *rle_data, int address) {
 	ram[GBASL]=0;			/* input address */
 	ram[GBASH]=0;			/* we fake this in this environment */
 
-	x=0;				/* Set X and Y registers to 0 */
-	y=0;
+	X=0;				/* Set X and Y registers to 0 */
+	Y=0;
 
 	ram[BASL]=address&0xff;		/* output address? */
 	ram[BASH]=(address>>8)&0xff;
@@ -862,51 +862,51 @@ int grsim_unrle_original(unsigned char *rle_data, int address) {
 	ram[CV]=0;
 
 	/* Read xsize, put in CH */
-	ram[CH]=rle_data[y_indirect(GBASL,y)];
-	y++;
+	ram[CH]=rle_data[y_indirect(GBASL,Y)];
+	Y++;
 
 	/* Skip ysize, we won't need it */
-	y++;
+	Y++;
 
 	while(1) {
 		/* Get run length into a */
-		a=rle_data[y_indirect(GBASL,y)];
+		A=rle_data[y_indirect(GBASL,Y)];
 
 		/* 0xff is a special value meaning end */
-		if (a==0xff) break;
+		if (A==0xff) break;
 
 		/* Store run length into TEMP */
-		ram[TEMP]=a;
+		ram[TEMP]=A;
 
 		/* 16-bit increment of GBASL:GBASH */
-		y++;
-		if (y==0) ram[GBASH]++;
+		Y++;
+		if (Y==0) ram[GBASH]++;
 
 		/* Get the color into A */
 
-		a=rle_data[y_indirect(GBASL,y)];
+		A=rle_data[y_indirect(GBASL,Y)];
 
 		/* 16-bit increment of GBASL:GBASH */
-		y++;
-		if (y==0) ram[GBASH]++;
+		Y++;
+		if (Y==0) ram[GBASH]++;
 
 		/* Push y on stack */
-		s=y;
-		y=0;
+		s=Y;
+		Y=0;
 
 		while(1) {
 			/* store out color */
-			ram[y_indirect(BASL,y)]=a;
+			ram[y_indirect(BASL,Y)]=A;
 
 			/* 16-bit increment of output pointer */
 			ram[BASL]++;
 			if (ram[BASL]==0) ram[BASH]++;
 
 			/* increment size */
-			x++;
+			X++;
 
 			/* if size longer than width, adjust */
-			if (x>=ram[CH]) {
+			if (X>=ram[CH]) {
 				if (ram[BASL]>0xa7) ram[BASH]++;
 				ram[BASL]+=0x58;
 				ram[CV]+=2;
@@ -921,7 +921,7 @@ int grsim_unrle_original(unsigned char *rle_data, int address) {
 						ram[BASH]=ram[BASH]-0x3;
 					}
 				}
-				x=0;
+				X=0;
 			}
 
 			/* repeat until use up all of run length */
@@ -929,7 +929,7 @@ int grsim_unrle_original(unsigned char *rle_data, int address) {
 			if (ram[TEMP]==0) break;
 		}
 		/* restore y from stack */
-		y=s;
+		Y=s;
 	}
 
 	return 0;
@@ -942,8 +942,8 @@ int grsim_unrle(unsigned char *rle_data, int address) {
 	ram[GBASL]=0;			/* input address */
 	ram[GBASH]=0;			/* we fake this in this environment */
 
-	x=0;				/* Set X and Y registers to 0 */
-	y=0;
+	X=0;				/* Set X and Y registers to 0 */
+	Y=0;
 
 	ram[BASL]=address&0xff;		/* output address? */
 	ram[BASH]=(address>>8)&0xff;
@@ -951,41 +951,40 @@ int grsim_unrle(unsigned char *rle_data, int address) {
 	ram[CV]=0;
 
 	/* Read xsize, put in CH */
-	ram[CH]=rle_data[y_indirect(GBASL,y)];
-	y++;
+	ram[CH]=rle_data[y_indirect(GBASL,Y)];
+	Y++;
 
 	/* Skip ysize, we won't need it */
-//	y++;
+//	Y++;
 
 	while(1) {
 
 		/* Get byte into A */
-		a=rle_data[y_indirect(GBASL,y)];
+		A=rle_data[y_indirect(GBASL,Y)];
 
 		/* 0xa1 is a special value meaning end */
-		if (a==0xa1) break;
+		if (A==0xa1) break;
 
 		/* Store run length into TEMP */
-		if ((a&0xf0)==0xa0) {
-			if ((a&0xf)==0) {
+		if ((A&0xf0)==0xa0) {
+			if ((A&0xf)==0) {
 				/* 16-bit increment of GBASL:GBASH */
-				y++;
-				if (y==0) ram[GBASH]++;
-
-				a=rle_data[y_indirect(GBASL,y)];
-				ram[TEMP]=a;
+				Y++;
+				if (Y==0) ram[GBASH]++;
 
+				A=rle_data[y_indirect(GBASL,Y)];
+				ram[TEMP]=A;
 			}
 			else {
-				ram[TEMP]=a&0xf;
+				ram[TEMP]=A&0xf;
 			}
 
 			/* 16-bit increment of GBASL:GBASH */
-			y++;
-			if (y==0) ram[GBASH]++;
+			Y++;
+			if (Y==0) ram[GBASH]++;
 
 			/* Get the color into A */
-			a=rle_data[y_indirect(GBASL,y)];
+			A=rle_data[y_indirect(GBASL,Y)];
 
 		}
 		else {
@@ -993,31 +992,31 @@ int grsim_unrle(unsigned char *rle_data, int address) {
 		}
 
 		/* 16-bit increment of GBASL:GBASH */
-		y++;
-		if (y==0) ram[GBASH]++;
+		Y++;
+		if (Y==0) ram[GBASH]++;
 
 		/* Push y on stack */
-		s=y;
-		y=0;
+		s=Y;
+		Y=0;
 
 #if 0
 	{
-		printf("Run=%d Color=%x\n",ram[TEMP],a);
+		printf("Run=%d Color=%x\n",ram[TEMP],A);
 	}
 #endif
 		while(1) {
 			/* store out color */
-			ram[y_indirect(BASL,y)]=a;
+			ram[y_indirect(BASL,Y)]=A;
 
 			/* 16-bit increment of output pointer */
 			ram[BASL]++;
 			if (ram[BASL]==0) ram[BASH]++;
 
 			/* increment size */
-			x++;
+			X++;
 
 			/* if size longer than width, adjust */
-			if (x>=ram[CH]) {
+			if (X>=ram[CH]) {
 				if (ram[BASL]>0xa7) ram[BASH]++;
 				ram[BASL]+=0x58;
 				ram[CV]+=2;
@@ -1032,7 +1031,7 @@ int grsim_unrle(unsigned char *rle_data, int address) {
 						ram[BASH]=ram[BASH]-0x3;
 					}
 				}
-				x=0;
+				X=0;
 			}
 
 			/* repeat until use up all of run length */
@@ -1040,7 +1039,7 @@ int grsim_unrle(unsigned char *rle_data, int address) {
 			if (ram[TEMP]==0) break;
 		}
 		/* restore y from stack */
-		y=s;
+		Y=s;
 
 #if 0
 	{
@@ -1070,10 +1069,10 @@ int basic_vlin(int y1, int y2, int at) {
 
 	if (y1>y2) { ram[H2]=y1; ram[V2]=y1; ram[FIRST]=y2; }
 	else       { ram[H2]=y2; ram[V2]=y2; ram[FIRST]=y1; }
-	x=at;
+	X=at;
 
-	if (x>40) {
-		fprintf(stderr,"Error!  AT too large %d!\n",x);
+	if (X>40) {
+		fprintf(stderr,"Error!  AT too large %d!\n",X);
 	}
 
 //VLIN  JSR LINCOOR
@@ -1084,12 +1083,12 @@ int basic_vlin(int y1, int y2, int at) {
 //F24A- A5 F0    2090        LDA FIRST    TOP END OF LINE IN A-REG
 //F24C- 4C 28 F8 2100        JMP MON.VLINE     LET MONITOR DRAW LINE
 
-	y=x;
-	if (y>=40) {
-		fprintf(stderr,"X value to big in vline %d\n",y);
+	Y=X;
+	if (Y>=40) {
+		fprintf(stderr,"X value to big in vline %d\n",Y);
 		return -1;
 	}
-	a=ram[FIRST];
+	A=ram[FIRST];
 
 	vline();
 
@@ -1108,7 +1107,7 @@ int grsim_put_sprite_page(int page, unsigned char *sprite_data, int xpos, int yp
 	int cycles=0;
 
 	ptr=sprite_data;
-	x=*ptr;
+	X=*ptr;
 	ptr++;
 	ram[CV]=*ptr;
 	ptr++;
@@ -1122,29 +1121,29 @@ int grsim_put_sprite_page(int page, unsigned char *sprite_data, int xpos, int yp
 		address+=(page)<<8;
 		address+=xpos;
 							cycles+=36;
-		for(i=0;i<x;i++) {
-			a=*ptr;
+		for(i=0;i<X;i++) {
+			A=*ptr;
 							cycles+=17;
 			// all transparent, skip
-			if (a==0xaa) {
+			if (A==0xaa) {
 			}
 			// bottom transparent
-			else if ((a&0xf0)==0xa0) {
+			else if ((A&0xf0)==0xa0) {
 							cycles+=8;
 				ram[address]&=0xf0;
-				ram[address]|=(a&0xf);
+				ram[address]|=(A&0xf);
 							cycles+=19;
 			}
 			// top transparent
-			else if ((a&0x0f)==0xa) {
+			else if ((A&0x0f)==0xa) {
 							cycles+=8;
 				ram[address]&=0x0f;
-				ram[address]|=(a&0xf0);
+				ram[address]|=(A&0xf0);
 							cycles+=19;
 			}
 			else {
 							cycles+=8;
-				ram[address]=a;
+				ram[address]=A;
 							cycles+=19;
 			}
 			ptr++;
@@ -1235,7 +1234,7 @@ int text(void) {
 
 	soft_switch(LOWSCR);	// LDA LOWSCR ($c054)
 	soft_switch(TXTSET);	// LDA TXTSET ($c051);
-	a=0;
+	A=0;
 
 	setwnd();
 
@@ -1247,42 +1246,42 @@ static void scroll(void) {
 
 	// fc70
 
-	a=ram[WNDTOP];
-	s=a;
+	A=ram[WNDTOP];
+	s=A;
 	vtabz();
 
 	// SCRL1
 scrl1:
-	a=ram[BASL];
-	ram[BAS2L]=a;
-	a=ram[BASH];
-	ram[BAS2H]=a;
-	y=ram[WNDWDTH];
-	y--;
-	a=s;
-	a+=1;
-	if (a>=ram[WNDBTM]) {
+	A=ram[BASL];
+	ram[BAS2L]=A;
+	A=ram[BASH];
+	ram[BAS2H]=A;
+	Y=ram[WNDWDTH];
+	Y--;
+	A=s;
+	A+=1;
+	if (A>=ram[WNDBTM]) {
 		// SCRL3
-		y=0;
+		Y=0;
 		cleolz();
 		rom_vtab();
 		return;
 	}
-	s=a;
+	s=A;
 	vtabz();
 	// SCRL2
 scrl2:
-	a=ram[y_indirect(BASL,y)];
-	ram[y_indirect(BAS2L,y)]=a;
-	y--;
-	if (y<0x80) goto scrl2;
+	A=ram[y_indirect(BASL,Y)];
+	ram[y_indirect(BAS2L,Y)]=A;
+	Y--;
+	if (Y<0x80) goto scrl2;
 	goto scrl1;
 }
 
 static void lf(void) {
 	ram[CV]=ram[CV]+1;
-	a=ram[CV];
-	if (a<ram[WNDBTM]) {
+	A=ram[CV];
+	if (A<ram[WNDBTM]) {
 		vtabz();
 		return;
 	}
@@ -1291,8 +1290,8 @@ static void lf(void) {
 }
 
 static void cr(void) {
-	a=0x00;
-	ram[CH]=a;
+	A=0x00;
+	ram[CH]=A;
 	lf();
 }
 
@@ -1303,8 +1302,8 @@ static void bell1(void) {
 
 static void up(void) {
 
-	a=ram[WNDTOP];
-	if (a>ram[CV]) return;
+	A=ram[WNDTOP];
+	if (A>ram[CV]) return;
 
 	ram[CV]=ram[CV]-1;
 	rom_vtab();
@@ -1317,8 +1316,8 @@ static void bs(void) {
 	/* still positive */
 	if (ram[CH]<0x80) return;
 
-	a=ram[WNDWDTH];
-	ram[CH]=a;
+	A=ram[WNDWDTH];
+	ram[CH]=A;
 	ram[CH]=ram[CH]-1;
 
 	up();
@@ -1328,14 +1327,14 @@ static void storadv(void) {
 
 	// fbf0
 
-	y=ram[CH];
-	ram[y_indirect(BASL,y)]=a;
+	Y=ram[CH];
+	ram[y_indirect(BASL,Y)]=A;
 
 	// advance
 
 	ram[CH]=ram[CH]+1;
-	a=ram[CH];
-	if (a>=ram[WNDWDTH]) {
+	A=ram[CH];
+	if (A>=ram[WNDWDTH]) {
 		cr();
 	}
 
@@ -1344,34 +1343,34 @@ static void storadv(void) {
 static void vidout(void) {
 	// fbfd
 
-	if (a>=0xa0) {
+	if (A>=0xa0) {
 		storadv();
 		return;
 	}
 
 	/* Control Characters */
-	y=a;
+	Y=A;
 	// if bit 7 is set then we set negative flag
 	// BPL storadv
-	if (a<0x80) {
+	if (A<0x80) {
 		storadv();
 		return;
 	}
 
 	/* carriage return */
-	if (a==0x8d) {
+	if (A==0x8d) {
 		cr();
 		return;
 	}
 
 	/* linefeed */
-	if (a==0x8a) {
+	if (A==0x8a) {
 		lf();
 		return;
 	}
 
 	/* backspace */
-	if (a==0x88) {
+	if (A==0x88) {
 		bs();
 		return;
 	}
@@ -1392,19 +1391,19 @@ static void cout1(void) {
 
 	unsigned char s;
 
-	if (a<0xa0) {
+	if (A<0xa0) {
 	}
 	else {
-		a=a&ram[INVFLG];
+		A=A&ram[INVFLG];
 	}
 	// coutz
-	ram[YSAV1]=y;
-	s=a;
+	ram[YSAV1]=Y;
+	s=A;
 
 	vidwait();
 
-	a=s;
-	y=ram[YSAV1];
+	A=s;
+	Y=ram[YSAV1];
 
 }
 
@@ -1422,26 +1421,26 @@ static void outdo(void) {
 	unsigned char s;
 
 	/* Print char in the accumulator */
-	a=a|0x80;		/* raw ascii has high bit on Apple II */
-	if (a<0xa0) {
+	A=A|0x80;		/* raw ascii has high bit on Apple II */
+	if (A<0xa0) {
 		/* skip if control char? */
 	}
 	else {
-		a=a|ram[FLASH];
+		A=A|ram[FLASH];
 	}
 	cout();
-	a=a&0x7f;	// ?
-	s=a;		// pha
-	a=ram[SPEEDZ];
+	A=A&0x7f;	// ?
+	s=A;		// pha
+	A=ram[SPEEDZ];
 	wait(); 	// this is BASIC, slow down if speed set
-	a=s;
+	A=s;
 }
 
 static void crdo(void) {
 	// DAFB
-	a=13;	// carriage return
+	A=13;	// carriage return
 	outdo();
-	a=a^0xff;		/* negate for some reason? */
+	A=A^0xff;		/* negate for some reason? */
 }
 
 void basic_htab(int xpos) {
@@ -1451,16 +1450,16 @@ void basic_htab(int xpos) {
 	// F7E7
 
 
-	x=xpos;	// JSR GETBYT
-	x--;	// DEX
-	a=x;	// TXA
-	while(a>=40) {
-		s=a;	// PHA
+	X=xpos;	// JSR GETBYT
+	X--;	// DEX
+	A=X;	// TXA
+	while(A>=40) {
+		s=A;	// PHA
 		crdo();
-		a=s;	// PLA
-		a-=40;
+		A=s;	// PLA
+		A-=40;
 	}
-	ram[CH]=a;	// STA MON.CH
+	ram[CH]=A;	// STA MON.CH
 
 	// KRW for the win!
 
@@ -1470,17 +1469,17 @@ static void tabv(void) {
 
 	// TABV
 	// fb5b
-	ram[CV]=a;
+	ram[CV]=A;
 	rom_vtab();
 }
 
 void basic_vtab(int ypos) {
 	// f256
-	x=ypos;
-	x--;		/* base on zero */
-	a=x;
+	X=ypos;
+	X--;		/* base on zero */
+	A=X;
 
-	if (a>23) {
+	if (A>23) {
 		fprintf(stderr,"Error, vtab %d too big\n",ypos);
 		return;
 	}
@@ -1492,7 +1491,7 @@ void basic_print(char *string) {
 	int i;
 
 	for(i=0;i<strlen(string);i++) {
-		a=string[i];
+		A=string[i];
 		outdo();
 	}
 
@@ -1500,20 +1499,20 @@ void basic_print(char *string) {
 
 void basic_inverse(void) {
 	// F277
-	a=0x3f;
-	x=0;
-	ram[INVFLG]=a;
-	ram[FLASH]=x;
+	A=0x3f;
+	X=0;
+	ram[INVFLG]=A;
+	ram[FLASH]=X;
 
 	return;
 }
 
 void basic_normal(void) {
 	// F273
-	a=0xff;
-	x=0;
-	ram[INVFLG]=a;
-	ram[FLASH]=x;
+	A=0xff;
+	X=0;
+	ram[INVFLG]=A;
+	ram[FLASH]=X;
 
 	return;
 }
@@ -1591,50 +1590,50 @@ static unsigned short vlin_hi;
 
 int vlin(int y1, int y2, int at) {
 
-	x=y1;
+	X=y1;
 	ram[V2]=y2;
-	y=at;
+	Y=at;
 
 vlin_loop:
 //	for(a=y1;a<y2;a++) {
 
-		ram[TEMPY]=y;
-		a=x;
-		y=a/2;
+		ram[TEMPY]=Y;
+		A=X;
+		Y=A/2;
 
-		ram[OUTL]=gr_addr_lookup[y]&0xff;
-		ram[OUTH]=(gr_addr_lookup[y]>>8)&0xff;
+		ram[OUTL]=gr_addr_lookup[Y]&0xff;
+		ram[OUTH]=(gr_addr_lookup[Y]>>8)&0xff;
 
 		ram[OUTH]+=ram[DRAW_PAGE];
 
-		vlin_hi=x&1;
+		vlin_hi=X&1;
 
-		y=ram[TEMPY];	// y=at;
+		Y=ram[TEMPY];	// y=at;
 
 		if (vlin_hi) {
-			ram[y_indirect(OUTL,y)]=ram[y_indirect(OUTL,y)]&0x0f;
-			ram[y_indirect(OUTL,y)]|=ram[COLOR]&0xf0;
+			ram[y_indirect(OUTL,Y)]=ram[y_indirect(OUTL,Y)]&0x0f;
+			ram[y_indirect(OUTL,Y)]|=ram[COLOR]&0xf0;
 		}
 		else {
-			ram[y_indirect(OUTL,y)]=ram[y_indirect(OUTL,y)]&0xf0;
-			ram[y_indirect(OUTL,y)]|=ram[COLOR]&0x0f;
+			ram[y_indirect(OUTL,Y)]=ram[y_indirect(OUTL,Y)]&0xf0;
+			ram[y_indirect(OUTL,Y)]|=ram[COLOR]&0x0f;
 		}
-	x++;
-	if (x<ram[V2]) goto vlin_loop;
+	X++;
+	if (X<ram[V2]) goto vlin_loop;
 
 	return 0;
 }
 
 int hlin_double_continue(int width) {
 
-	x=width;
+	X=width;
 
 hlin_loop:
-	y=0;
-	ram[y_indirect(GBASL,y)]=ram[COLOR];
+	Y=0;
+	ram[y_indirect(GBASL,Y)]=ram[COLOR];
 	ram[GBASL]++;
-	x--;
-	if (x!=0) goto hlin_loop;
+	X--;
+	if (X!=0) goto hlin_loop;
 
 //	ram[GBASL]+=width;
 
@@ -1646,11 +1645,11 @@ hlin_loop:
 int hlin_setup(int page, int x1, int x2, int at) {
 
 	// page, y, V2, A
-	a=at;
-	y=at/2;
+	A=at;
+	Y=at/2;
 
-	ram[GBASL]=(gr_addr_lookup[y])&0xff;
-	ram[GBASH]=(gr_addr_lookup[y]>>8);
+	ram[GBASL]=(gr_addr_lookup[Y])&0xff;
+	ram[GBASH]=(gr_addr_lookup[Y]>>8);
 
 	ram[GBASH]+=(page);
 
@@ -1797,32 +1796,38 @@ void move_and_print(char *string) {
 
 void print(char *string) {
 
+	int y;
+
 	for(y=0;y<strlen(string);y++) {
-		a=string[y];
-		a=a|0x80;
-		ram[y_indirect(BASL,y)]=a;
+		A=string[y];
+		A=A|0x80;
+		ram[y_indirect(BASL,y)]=A;
 	}
 	ram[BASL]+=strlen(string);
 }
 
 void print_inverse(char *string) {
 
-	for(y=0;y<strlen(string);y++) {
-		a=string[y];
-		if ((a>='a') && (a<='z')) a&=~0x20;	// convert to uppercase
-		a=(a&0x3f);
+	int y;
 
-		ram[y_indirect(BASL,y)]=a;
+	for(y=0;y<strlen(string);y++) {
+		A=string[y];
+		if ((A>='a') && (A<='z')) A&=~0x20;	// convert to uppercase
+		A=(A&0x3f);
+
+		ram[y_indirect(BASL,y)]=A;
 	}
 	ram[BASL]+=strlen(string);
 }
 
 void print_flash(char *string) {
 
+	int y;
+
 	for(y=0;y<strlen(string);y++) {
-		a=string[y];
-		a=(a&0x3f)|0x40;
-		ram[y_indirect(BASL,y)]=a;
+		A=string[y];
+		A=(A&0x3f)|0x40;
+		ram[y_indirect(BASL,y)]=A;
 	}
 	ram[BASL]+=strlen(string);
 }
diff --git a/utils/gr-sim/gr-sim.h b/utils/gr-sim/gr-sim.h
index d3aa9324..a1f30497 100644
--- a/utils/gr-sim/gr-sim.h
+++ b/utils/gr-sim/gr-sim.h
@@ -1,5 +1,5 @@
 extern unsigned char ram[128*1024];
-extern unsigned char a,y,x;
+extern unsigned char A,Y,X;
 
 int grsim_input(void);
 int grsim_update(void);
@@ -120,8 +120,12 @@ void clear_bottom(void);
 void clear_screens_notext(void);
 void clear_all(void);
 
+/* hgr-sim.c */
 int hgr(void);
 int hplot(int xx, int yy);
 int hplot_to(int xx, int yy);
 int hcolor_equals(int color);
-
+void bkgnd(void);
+void hclr(void);
+void hposn(void);
+int hplot(int xx, int yy);
diff --git a/utils/gr-sim/hgr-sim.c b/utils/gr-sim/hgr-sim.c
index 6ca81b37..9c49d4be 100644
--- a/utils/gr-sim/hgr-sim.c
+++ b/utils/gr-sim/hgr-sim.c
@@ -10,39 +10,39 @@ static void color_shift(void) {
 	asl();
 	cmp(0xc0);
 
-	if (!n) goto done_color_shift;
+	if (!N) goto done_color_shift;
 
-	a=ram[HGR_BITS];
-	a=a^0x7f;
-	ram[HGR_BITS]=a;
+	A=ram[HGR_BITS];
+	A=A^0x7f;
+	ram[HGR_BITS]=A;
 
 done_color_shift:
 	;	// rts
 }
 
-static void bkgnd(void) {
+void bkgnd(void) {
 	// F3F6
-	a=ram[HGR_PAGE];
-	ram[HGR_SHAPE+1]=a;
-	y=0;
-	ram[HGR_SHAPE]=y;
+	A=ram[HGR_PAGE];
+	ram[HGR_SHAPE+1]=A;
+	Y=0;
+	ram[HGR_SHAPE]=Y;
 bkgnd_loop:
-	a=ram[HGR_BITS];
+	A=ram[HGR_BITS];
 
-	ram[y_indirect(HGR_SHAPE,y)]=a;
+	ram[y_indirect(HGR_SHAPE,Y)]=A;
 
 	color_shift();
 
-	y++;
-	if (y==0) {
+	Y++;
+	if (Y==0) {
 	}
 	else {
 		goto bkgnd_loop;
 	}
 	ram[HGR_SHAPE+1]+=1;
-	a=ram[HGR_SHAPE+1];
-	a&=0x1f;			// see if $40 or $60
-	if (a!=0) {
+	A=ram[HGR_SHAPE+1];
+	A&=0x1f;			// see if $40 or $60
+	if (A!=0) {
 		goto bkgnd_loop;
 	}
 	// rts
@@ -50,15 +50,15 @@ bkgnd_loop:
 
 void hclr(void) {
 	// F3F2
-	a=0;			// black background
-	ram[HGR_BITS]=a;
+	A=0;			// black background
+	ram[HGR_BITS]=A;
 	bkgnd();
 
 }
 
 static void sethpg(void) {
 	// F3EA
-	ram[HGR_PAGE]=a;
+	ram[HGR_PAGE]=A;
 	soft_switch(HIRES);	// LDA SW.HIRES
 	soft_switch(TXTCLR);	// LDA SW.TXTCLR
 
@@ -69,7 +69,7 @@ static void sethpg(void) {
 int hgr(void) {
 
 	// F3E2
-	a=0x20;			// HIRES Page 1 at $2000
+	A=0x20;			// HIRES Page 1 at $2000
 	soft_switch(LOWSCR);	// BIT SW.LOWSCR Use PAGE1 ($C054)
         soft_switch(MIXSET);    // BIT SW.MIXSET (Mixed text)
 	sethpg();
@@ -82,30 +82,30 @@ int hgr2(void) {
 	// F3D8
 	soft_switch(HISCR);	// BIT SW.HISCR Use PAGE2 ($C055)
 	soft_switch(MIXCLR);	// BIT SW.MIXCLR
-	a=0x40;			// HIRES Page 2 at $4000
+	A=0x40;			// HIRES Page 2 at $4000
 	sethpg();
 
         return 0;
 }
 
-static void hposn(void) {
+void hposn(void) {
 
 	unsigned char msktbl[]={0x81,0x82,0x84,0x88,0x90,0xA0,0xC0};
 
 	// F411
-	ram[HGR_Y]=a;
-	ram[HGR_X]=x;
-	ram[HGR_X+1]=y;
+	ram[HGR_Y]=A;
+	ram[HGR_X]=X;
+	ram[HGR_X+1]=Y;
 	pha();
-	a=a&0xC0;
-	ram[GBASL]=a;
+	A=A&0xC0;
+	ram[GBASL]=A;
 	lsr();
 	lsr();
-	a=a|ram[GBASL];
-	ram[GBASL]=a;
+	A=A|ram[GBASL];
+	ram[GBASL]=A;
 	pla();
 	// F423
-	ram[GBASH]=a;
+	ram[GBASH]=A;
 	asl();
 	asl();
 	asl();
@@ -115,43 +115,43 @@ static void hposn(void) {
 	asl();
 	ror_mem(GBASL);
 	lda(GBASH);
-	a=a&0x1f;
-	a=a|ram[HGR_PAGE];
-	ram[GBASH]=a;
+	A=A&0x1f;
+	A=A|ram[HGR_PAGE];
+	ram[GBASH]=A;
 
 	// F438
-	a=x;
+	A=X;
 	cpy(0);
-	if (z==1) goto hposn_2;
+	if (Z==1) goto hposn_2;
 
-	y=35;
+	Y=35;
 	adc(4);
 hposn_1:
 	iny();
 	// f442
 hposn_2:
 	sbc(7);
-	if (c==1) goto hposn_1;
-	ram[HGR_HORIZ]=y;
-	x=a;
-	a=msktbl[(x-0x100)+7];		// LDA MSKTBL-$100+7,X  BIT MASK
+	if (C==1) goto hposn_1;
+	ram[HGR_HORIZ]=Y;
+	X=A;
+	A=msktbl[(X-0x100)+7];		// LDA MSKTBL-$100+7,X  BIT MASK
 					// MSKTBL=F5B8
-	ram[HMASK]=a;
-	a=y;
+	ram[HMASK]=A;
+	A=Y;
 	lsr();
-	a=ram[HGR_COLOR];
-	ram[HGR_BITS]=a;
-	if (c) color_shift();
+	A=ram[HGR_COLOR];
+	ram[HGR_BITS]=A;
+	if (C) color_shift();
 }
 
 static void hplot0(void) {
 	// F457
 	hposn();
-	a=ram[HGR_BITS];
-	a=a^ram[y_indirect(GBASL,y)];
-	a=a&ram[HMASK];
-	a=a^ram[y_indirect(GBASL,y)];
-	ram[y_indirect(GBASL,y)]=a;
+	A=ram[HGR_BITS];
+	A=A^ram[y_indirect(GBASL,Y)];
+	A=A&ram[HMASK];
+	A=A^ram[y_indirect(GBASL,Y)];
+	ram[y_indirect(GBASL,Y)]=A;
 }
 
 static void hfns(int xx, int yy) {
@@ -167,9 +167,9 @@ static void hfns(int xx, int yy) {
 		return;
 	}
 
-	x=(xx&0xff);
-	y=(xx>>8);
-	a=yy;
+	X=(xx&0xff);
+	Y=(xx>>8);
+	A=yy;
 
 }
 
@@ -185,56 +185,56 @@ int hplot(int xx, int yy) {
 
 static void move_left_or_right(void) {
 	// F465
-	if (n==0) goto move_right;
+	if (N==0) goto move_right;
 
-	a=ram[HMASK];
+	A=ram[HMASK];
 	lsr();
-	if (c==1) goto lr_2;
-	a=a^0xc0;
+	if (C==1) goto lr_2;
+	A=A^0xc0;
 lr_1:
-	ram[HMASK]=a;
+	ram[HMASK]=A;
 	return;
 lr_2:
 	dey();
-	if (n==0) goto lr_3;
-	y=39;
+	if (N==0) goto lr_3;
+	Y=39;
 lr_3:
-	a=0xc0;
+	A=0xc0;
 lr_4:
-	ram[HMASK]=a;
-	ram[HGR_HORIZ]=y;
-	a=ram[HGR_BITS];
+	ram[HMASK]=A;
+	ram[HGR_HORIZ]=Y;
+	A=ram[HGR_BITS];
 	color_shift();
 	return;
 
 move_right:
-	a=ram[HMASK];
+	A=ram[HMASK];
 	asl();
-	a=a^0x80;
-	if (a&0x80) goto lr_1;
-	a=0x81;
+	A=A^0x80;
+	if (A&0x80) goto lr_1;
+	A=0x81;
 	iny();
 	cpy(40);
-	if (c==0) goto lr_4;
-	y=0;
+	if (C==0) goto lr_4;
+	Y=0;
 	goto lr_4;
 
 }
 
 static void move_up_or_down(void) {
 	// F4D3
-	if (n==1) goto move_down;
+	if (N==1) goto move_down;
 
-	c=0;
+	C=0;
 	lda(GBASH);
 	bit(0x1c);		// CON.1C
-	if (z!=1) goto mu_5;
+	if (Z!=1) goto mu_5;
 	asl_mem(GBASL);
-	if (c==1) goto mu_3;
+	if (C==1) goto mu_3;
 	bit(0x03);		// CON.03
-	if (z==1) goto mu_1;
+	if (Z==1) goto mu_1;
 	adc(0x1f);
-	c=1;
+	C=1;
 	goto mu_4;
 	// F4Eb
 mu_1:
@@ -242,11 +242,11 @@ mu_1:
 	pha();
 	lda(GBASL);
 	adc(0xb0);
-	if (c==1) goto mu_2;
+	if (C==1) goto mu_2;
 	adc(0xf0);
 	// f4f6
 mu_2:
-	ram[GBASL]=a;
+	ram[GBASL]=A;
 	pla();
 	goto mu_4;
 mu_3:
@@ -256,7 +256,7 @@ mu_4:
 mu_5:
 	adc(0xfc);
 ud_1:
-	ram[GBASH]=a;
+	ram[GBASH]=A;
 	return;
 
 	// f505
@@ -264,20 +264,20 @@ move_down:
 	lda(GBASH);
 	adc(4);
 	bit(0x1c);
-	if (z!=1) goto ud_1;
+	if (Z!=1) goto ud_1;
 	asl_mem(GBASL);
-	if (c==0) goto md_2;
+	if (C==0) goto md_2;
 	adc(0xe0);
-	c=0;
+	C=0;
 	bit(0x4);
-	if (z==1) goto md_3;
+	if (Z==1) goto md_3;
 	lda(GBASL);
 	adc(0x50);
-	a=a^0xf0;
-	if (a==0) goto md_1;
-	a=a^0xf0;
+	A=A^0xf0;
+	if (A==0) goto md_1;
+	A=A^0xf0;
 md_1:
-	ram[GBASL]=a;
+	ram[GBASL]=A;
 	lda(HGR_PAGE);
 	goto md_3;
 md_2:
@@ -292,82 +292,82 @@ static void hglin(void) {
 
 	// F53A
 	pha();
-	c=1;
+	C=1;
 	sbc(ram[HGR_X]);
 	pha();
-	a=x;
+	A=X;
 	sbc(ram[HGR_X+1]);
-	ram[HGR_QUADRANT]=a;
+	ram[HGR_QUADRANT]=A;
 	// F544
-	if (c==1) goto hglin_1;
+	if (C==1) goto hglin_1;
 	pla();
-	a=a^0xff;
+	A=A^0xff;
 	adc(1);
 	pha();
 	lda_const(0);
 	sbc(ram[HGR_QUADRANT]);
 	// F550
 hglin_1:
-	ram[HGR_DX+1]=a;
-	ram[HGR_E+1]=a;
+	ram[HGR_DX+1]=A;
+	ram[HGR_E+1]=A;
 	pla();
-	ram[HGR_DX]=a;
-	ram[HGR_E]=a;
+	ram[HGR_DX]=A;
+	ram[HGR_E]=A;
 	pla();
-	ram[HGR_X]=a;
-	ram[HGR_X+1]=x;
-	a=y;
-	c=0;
+	ram[HGR_X]=A;
+	ram[HGR_X+1]=X;
+	A=Y;
+	C=0;
 	sbc(ram[HGR_Y]);
-	if (c==0) goto hglin_2;
-	a=a^0xff;
+	if (C==0) goto hglin_2;
+	A=A^0xff;
 	adc(0xfe);
 hglin_2:
 	// F568
-	ram[HGR_DY]=a;
-	ram[HGR_Y]=y;
+	ram[HGR_DY]=A;
+	ram[HGR_Y]=Y;
 	ror_mem(HGR_QUADRANT);
-	c=1;
+	C=1;
 	sbc(ram[HGR_DX]);
-	x=a;
+	X=A;
 	lda_const(0xff);
 	sbc(ram[HGR_DX+1]);
-	ram[HGR_COUNT]=a;
+	ram[HGR_COUNT]=A;
 	ldy(HGR_HORIZ);
 	goto movex2;	// always?
 	// f57c
 movex:
 	asl();
 	move_left_or_right();
-	c=1;
+	C=1;
 
 	// f581
 movex2:
 	lda(HGR_E);
 	adc(ram[HGR_DY]);
-	ram[HGR_E]=a;
+	ram[HGR_E]=A;
 	lda(HGR_E+1);
 	sbc(0);
 movex2_1:
-	ram[HGR_E+1]=a;
-	lda(y_indirect(GBASL,y));
-	a=a^ram[HGR_BITS];
-	a=a&ram[HMASK];
-	a=a^ram[y_indirect(GBASL,y)];
-	ram[y_indirect(GBASL,y)]=a;
+	ram[HGR_E+1]=A;
+	lda(y_indirect(GBASL,Y));
+	A=A^ram[HGR_BITS];
+	A=A&ram[HMASK];
+	A=A^ram[y_indirect(GBASL,Y)];
+	ram[y_indirect(GBASL,Y)]=A;
 	inx();
-	if (z!=1) goto movex2_2;
+	if (Z!=1) goto movex2_2;
 	ram[HGR_COUNT]++;
 	if (ram[HGR_COUNT]==0) return;
 	// F59e
 movex2_2:
 	lda(HGR_QUADRANT);
-	if (c==1) goto movex;
+	if (C==1) goto movex;
 	move_up_or_down();
-	c=0;
+	C=0;
 	lda(HGR_E);
 	adc(ram[HGR_DX]);
-	ram[HGR_E]=a;
+	ram[HGR_E]=A;
 	lda(HGR_E+1);
 	adc(ram[HGR_DX+1]);
 	goto movex2_1;
@@ -377,10 +377,10 @@ int hplot_to(int xx, int yy) {
 
 	// F712
 	hfns(xx,yy);
-	ram[DSCTMP]=y;
-	y=a;
-	a=x;
-	x=ram[DSCTMP];
+	ram[DSCTMP]=Y;
+	Y=A;
+	A=X;
+	X=ram[DSCTMP];
 	hglin();
 
 	return 0;
@@ -391,14 +391,14 @@ int hcolor_equals(int color) {
 	unsigned char colortbl[8]={0x00,0x2A,0x55,0x7F,0x80,0xAA,0xD5,0xFF};
 
 	// F6E9
-	x=color;
-	if (x>7) {
+	X=color;
+	if (X>7) {
 		printf("HCOLOR out of range!\n");
 		return -1;
 	}
 
-	a=colortbl[x];
-	ram[HGR_COLOR]=a;
+	A=colortbl[X];
+	ram[HGR_COLOR]=A;
 
 	return 0;
 }
diff --git a/utils/gr-sim/hgr/Makefile b/utils/gr-sim/hgr/Makefile
index 70b33dab..b8446fc3 100644
--- a/utils/gr-sim/hgr/Makefile
+++ b/utils/gr-sim/hgr/Makefile
@@ -7,7 +7,8 @@ SDL_INCLUDE= `sdl-config --cflags`
 GR_SIM = ../gr-sim.a
 
 all:	fireworks fw_purple lines image_load hgr_view seven tunnel \
-	random16 scroll scroll-asm plasma_new plasma_test plasma_test64
+	random16 scroll scroll-asm plasma_new plasma_test plasma_test64 \
+	tunnel_small
 
 ###
 
@@ -49,6 +50,15 @@ tunnel:	tunnel.o $(GR_SIM)
 tunnel.o:	tunnel.c
 	$(CC) $(CFLAGS) -c tunnel.c
 
+###
+
+tunnel_small:	tunnel_small.o $(GR_SIM)
+	$(CC) -o tunnel_small tunnel_small.o $(GR_SIM) $(LFLAGS) $(SDL_LIBS)
+
+tunnel_small.o:	tunnel_small.c
+	$(CC) $(CFLAGS) -c tunnel_small.c
+
+
 
 ###
 
@@ -119,4 +129,5 @@ scroll-asm.o:	scroll-asm.c
 
 clean:	
 	rm -f *~ *.o fireworks lines image_load hgr_view fw_purple seven \
-		random16 scroll scroll-asm plasma_text plasma_text64 tunnel
+		random16 scroll scroll-asm plasma_text plasma_text64 tunnel \
+		tunnel_small
diff --git a/utils/gr-sim/hgr/fw_purple.c b/utils/gr-sim/hgr/fw_purple.c
index 9ceba3e7..73566a38 100644
--- a/utils/gr-sim/hgr/fw_purple.c
+++ b/utils/gr-sim/hgr/fw_purple.c
@@ -60,39 +60,39 @@ struct star_type {
 void random_6502(void) {
 
 	lda(SEED);			// lda seed
-	if (a==0) goto lowZero;		// beq lowZero ; $0000 and $8000 are special values to test for
+	if (A==0) goto lowZero;		// beq lowZero ; $0000 and $8000 are special values to test for
 					// ; Do a normal shift
 	asl_mem(SEED);			// asl seed
 	lda(SEED+1);			// lda seed+1
 	rol();				//  rol
-	if (c==0) goto noEor;		// bcc noEor
+	if (C==0) goto noEor;		// bcc noEor
 
 doEor:
 					// ; high byte is in .A
-	a=a^0x76;			// eor #>magic
-	ram[SEED+1]=a;			// sta seed+1
+	A=A^0x76;			// eor #>magic
+	ram[SEED+1]=A;			// sta seed+1
 	lda(SEED);			// lda seed
-	a=a^0x57;			// eor #<magic
-	ram[SEED]=a;			// sta seed
+	A=A^0x57;			// eor #<magic
+	ram[SEED]=A;			// sta seed
 	return;				//  rts
 
 
 lowZero:
 	lda(SEED+1);	// lda seed+1
-	if (a==0) goto doEor;
+	if (A==0) goto doEor;
 			// beq doEor ; High byte is also zero, so apply the EOR
 			// ; For speed, you could store 'magic' into 'seed' directly
 			// ; instead of running the EORs
 
 			//  ; wasn't zero, check for $8000
 	asl();		//  asl
-	if (a==0) goto noEor;
+	if (A==0) goto noEor;
 			//  beq noEor ; if $00 is left after the shift, then it was $80
-	if (c==1) goto doEor;
+	if (C==1) goto doEor;
 			// bcs doEor ; else, do the EOR based on the carry bit as usual
 
 noEor:
-	ram[SEED+1]=a;	// sta seed+1
+	ram[SEED+1]=A;	// sta seed+1
 
 	return;		// rts
 }
diff --git a/utils/gr-sim/hgr/random16.c b/utils/gr-sim/hgr/random16.c
index 79b4bde6..9066c1e3 100644
--- a/utils/gr-sim/hgr/random16.c
+++ b/utils/gr-sim/hgr/random16.c
@@ -32,7 +32,7 @@ unsigned short random16(void) {
 	path|=PATH_R16;
 
 	lda(SEEDL);	cycles+=3;
-	if (a==0) {
+	if (A==0) {
 		cycles+=3;
 		goto low_zero;
 	}
@@ -43,12 +43,12 @@ unsigned short random16(void) {
 	asl_mem(SEEDL);	cycles+=5;
 	lda(SEEDH);	cycles+=3;
 	rol();		cycles+=2;
-	if (c==1) {
+	if (C==1) {
 		cycles+=3;
 		goto five_cycle_do_eor;
 	}
 	cycles+=2;
-	if (c==0) {
+	if (C==0) {
 		cycles+=3;
 		goto two_cycle_no_eor;
 	}
@@ -63,10 +63,10 @@ three_cycle_do_eor:
 
 //do_eor:
 	path|=PATH_DEO;
-	a=a^0x76;	cycles+=2;
+	A=A^0x76;	cycles+=2;
 	sta(SEEDH);	cycles+=3;
 	lda(SEEDL);	cycles+=3;
-	a=a^0x57;	cycles+=2;
+	A=A^0x57;	cycles+=2;
 	sta(SEEDL);	cycles+=3;
 eor_rts:
 	cycles+=6;
@@ -91,7 +91,7 @@ two_cycle_no_eor:
 low_zero:
 	path|=PATH_LOZ;
 	lda(SEEDH);	cycles+=3;
-	if (a==0) {
+	if (A==0) {
 		cycles+=3;
 		goto eleven_cycle_do_eor;
 	}
@@ -100,7 +100,7 @@ low_zero:
 //ceo:
 	path|=PATH_CEO;
 	asl();	cycles+=2;
-	if (a==0) {
+	if (A==0) {
 		cycles+=3;
 		goto six_cycles_no_eor;
 	}
@@ -108,12 +108,12 @@ low_zero:
 
 //cep:
 	path|=PATH_CEP;
-	if (c==0) {
+	if (C==0) {
 		cycles+=3;
 		goto four_cycle_no_eor;
 	}
 	cycles+=2;
-	if (c==1) {
+	if (C==1) {
 		cycles+=3;
 		goto three_cycle_do_eor;
 	}
diff --git a/utils/gr-sim/hgr/scroll-asm.c b/utils/gr-sim/hgr/scroll-asm.c
index de8647af..c37c8be2 100644
--- a/utils/gr-sim/hgr/scroll-asm.c
+++ b/utils/gr-sim/hgr/scroll-asm.c
@@ -96,38 +96,38 @@ scroll_loop:
 left_one_loop:
 //	printf("%d %02x:%02x\n",count,ram[OUTH],ram[OUTL]);
 
-	for(y=0;y<40;y++) {
-		ram[CURRENT]=ram[y_indirect(OUTL,y)];
-		ram[NEXT]=ram[y_indirect(OUTL,y+1)];
+	for(Y=0;Y<40;Y++) {
+		ram[CURRENT]=ram[y_indirect(OUTL,Y)];
+		ram[NEXT]=ram[y_indirect(OUTL,Y+1)];
 		if ((count%7==2) || (count%7==6)) {
 			ram[HIGH]=ram[NEXT]&0x80;
 		}
 		else {
 			ram[HIGH]=ram[CURRENT]&0x80;
 		}
-		if (y==39) ram[NEXT]=ram[y_indirect(INL,0)];
+		if (Y==39) ram[NEXT]=ram[y_indirect(INL,0)];
 
-		a=ram[NEXT];
+		A=ram[NEXT];
 		and(0x3);
 		asl();
 		asl();
 		asl();
 		asl();
 		asl();
-		ram[NEXT]=a;
+		ram[NEXT]=A;
 
-		a=ram[CURRENT];
+		A=ram[CURRENT];
 		lsr();
 		lsr();			// current>>=2;
 		and(0x1f);		// current&=0x1f;
 		ora_mem(HIGH);
 		ora_mem(NEXT);
-		ram[y_indirect(OUTL,y)]=a;
+		ram[y_indirect(OUTL,Y)]=A;
 	}
 
-	for(y=0;y<40;y++) {
-		ram[CURRENT]=ram[y_indirect(INL,y)];
-		ram[NEXT]=ram[y_indirect(INL,y+1)];
+	for(Y=0;Y<40;Y++) {
+		ram[CURRENT]=ram[y_indirect(INL,Y)];
+		ram[NEXT]=ram[y_indirect(INL,Y+1)];
 		if ((count%7==2) ||(count%7==6)) {
 			ram[HIGH]=ram[NEXT]&0x80;
 		}
@@ -135,43 +135,43 @@ left_one_loop:
 			ram[HIGH]=ram[CURRENT]&0x80;
 		}
 
-		a=ram[NEXT];
+		A=ram[NEXT];
 		and(0x3);
 		asl();
 		asl();
 		asl();
 		asl();
 		asl();
-		ram[NEXT]=a;
+		ram[NEXT]=A;
 
-		a=ram[CURRENT];
+		A=ram[CURRENT];
 		lsr();
 		lsr();			// current>>=2;
 		and(0x1f);		// current&=0x1f;
 		ora_mem(HIGH);
 		ora_mem(NEXT);
-		ram[y_indirect(INL,y)]=a;
+		ram[y_indirect(INL,Y)]=A;
 	}
 
 
 
 	clc();
-	a=ram[INL];
+	A=ram[INL];
 	adc(0x80);
-	ram[INL]=a;
-	a=ram[INH];
+	ram[INL]=A;
+	A=ram[INH];
 	adc(0x0);
-	ram[INH]=a;
+	ram[INH]=A;
 
 	clc();
-	a=ram[OUTL];
+	A=ram[OUTL];
 	adc(0x80);
-	ram[OUTL]=a;
-	a=ram[OUTH];
+	ram[OUTL]=A;
+	A=ram[OUTH];
 	adc(0x0);
-	ram[OUTH]=a;
+	ram[OUTH]=A;
 
-	if (a!=0x60) goto left_one_loop;
+	if (A!=0x60) goto left_one_loop;
 
 	grsim_update();
 	ch=grsim_input();
diff --git a/utils/gr-sim/hgr/seven.c b/utils/gr-sim/hgr/seven.c
index ef766bcd..4a74399d 100644
--- a/utils/gr-sim/hgr/seven.c
+++ b/utils/gr-sim/hgr/seven.c
@@ -17,14 +17,14 @@ static void fancy_div(int d, int *q, int *r) {
 	// y=xhigh x=xlow a=??
 	// q in y, r in a
 
-	y=(d>>8)&0xff;
-	x=d&0xff;
+	Y=(d>>8)&0xff;
+	X=d&0xff;
 
-	a=x;
+	A=X;
 
 	sta(TEMP_R);
 
-	c=0;
+	C=0;
 	sta(HGR_HORIZ);		// 0
 	lsr();			// 0
 	lsr();			// 0
@@ -40,7 +40,7 @@ static void fancy_div(int d, int *q, int *r) {
 
 	// calc remainder
 
-	c=0;
+	C=0;
 	sta(HGR_HORIZ);
 	asl();
 	adc_mem(HGR_HORIZ);
@@ -49,7 +49,7 @@ static void fancy_div(int d, int *q, int *r) {
 	// HGR_HORIZ=x/7, A=HGR_HORIZ*7
 
 
-	c=1;
+	C=1;
 	eor(0xff);
 //	printf("%d+%d=",d&0xff,a);
 	adc(d&0xff);
@@ -61,8 +61,8 @@ static void fancy_div(int d, int *q, int *r) {
 //	sbc_mem(TEMP_R);
 //	tax();
 
-	if (y) {
-		c=0;
+	if (Y) {
+		C=0;
 		adc(4);
 		pha();
 		lda(HGR_HORIZ);
@@ -71,16 +71,16 @@ static void fancy_div(int d, int *q, int *r) {
 		pla();
 	}
 
-	if (a>6) {
-		c=1;
+	if (A>6) {
+		C=1;
 		sbc(7);
 		ram[HGR_HORIZ]++;
 	}
 
-	y=ram[HGR_HORIZ];
+	Y=ram[HGR_HORIZ];
 
-	*q=y;
-	*r=a;
+	*q=Y;
+	*r=A;
 }
 
 
diff --git a/utils/gr-sim/lz4/krw_decode.c b/utils/gr-sim/lz4/krw_decode.c
index b967da9c..a614a28f 100644
--- a/utils/gr-sim/lz4/krw_decode.c
+++ b/utils/gr-sim/lz4/krw_decode.c
@@ -27,7 +27,7 @@ static int cycles;
 
 static void getsrc(void) {
 //getsrc:
-	a=ram[y_indirect(LZ4_SRC,y)];	cycles+=5;	// lda 	(LZ4_SRC), y
+	A=ram[y_indirect(LZ4_SRC,Y)];	cycles+=5;	// lda 	(LZ4_SRC), y
 	ram[LZ4_SRC]++;			cycles+=5;	//inc	LZ4_SRC
 					cycles+=2;
 	if (ram[LZ4_SRC]!=0) {
@@ -42,29 +42,29 @@ done_getsrc:
 
 void buildcount(void) {
 //buildcount:
-	x=1;		cycles+=2;		// ??		// ldx	#1
-	ram[COUNT+1]=x; cycles+=3;		// ??		// stx	COUNT+1
+	X=1;		cycles+=2;		// ??		// ldx	#1
+	ram[COUNT+1]=X; cycles+=3;		// ??		// stx	COUNT+1
 	cmp(0xf);	cycles+=2;		// if 15, more complicated // cmp	#$0f
 	cycles+=2;
-	if (z==0) {
+	if (Z==0) {
 		cycles+=1;
 		goto done_buildcount;		// otherwise A is count // bne	++
 	}
 buildcount_loop:
-	ram[COUNT]=a;	cycles+=3;		//-	sta	count
+	ram[COUNT]=A;	cycles+=3;		//-	sta	count
 	getsrc();	cycles+=6;		//jsr	getsrc
-	x=a;		cycles+=2;		//tax
-	c=0;		cycles+=2;		//clc
+	X=A;		cycles+=2;		//tax
+	C=0;		cycles+=2;		//clc
 	adc(ram[COUNT]);cycles+=3;		//adc	COUNT
 	cycles+=2;
-	if (c==0) {
+	if (C==0) {
 		cycles+=1;
 		goto skip_buildcount;		// bcc	+
 	}
 	ram[COUNT+1]++;	cycles+=5;		//inc	COUNT+1
 skip_buildcount:
-	x++;		cycles+=2;		// check if x is 255	//+	inx
-	if (x==0) {
+	X++;		cycles+=2;		// check if x is 255	//+	inx
+	if (X==0) {
 		cycles+=1;
 		goto buildcount_loop;		// if so, add in next byte //beq	-
 	}
@@ -76,7 +76,7 @@ done_buildcount:
 
 static void putdst(void) {
 							// putdst:
-	ram[y_indirect(LZ4_DST,y)]=a; cycles+=6;	//	sta 	(LZ4_DST), y
+	ram[y_indirect(LZ4_DST,Y)]=A; cycles+=6;	//	sta 	(LZ4_DST), y
 	ram[LZ4_DST]++;		cycles+=5;		//	inc	LZ4_DST
 	cycles+=2;
 	if (ram[LZ4_DST]!=0) {
@@ -102,9 +102,9 @@ static void docopy(void) {
 						// docopy:
 docopy_label:
 	getput();	cycles+=6;		// jsr	getput
-	x--;		cycles+=2;		// dex
+	X--;		cycles+=2;		// dex
 	cycles+=2;
-	if (x!=0) {
+	if (X!=0) {
 		cycles+=1;
 		goto docopy_label;		// bne	docopy
 	}
@@ -132,18 +132,18 @@ int lz4_decode(void) {
 	//Peter Ferrie (peter.ferrie@gmail.com)
 // lz4_decode:
 
-	a=ram[LZ4_SRC];		cycles+=3;	// lda     LZ4_SRC
-	c=0;			cycles+=2;	// clc
+	A=ram[LZ4_SRC];		cycles+=3;	// lda     LZ4_SRC
+	C=0;			cycles+=2;	// clc
 	adc(ram[LZ4_END]);	cycles+=3;	// adc     LZ4_END
-	ram[LZ4_END]=a;		cycles+=3;	// sta     LZ4_END
-        a=ram[LZ4_SRC+1];	cycles+=3;	// lda     LZ4_SRC+1
+	ram[LZ4_END]=A;		cycles+=3;	// sta     LZ4_END
+        A=ram[LZ4_SRC+1];	cycles+=3;	// lda     LZ4_SRC+1
 	adc(ram[LZ4_END+1]);	cycles+=3;	// adc     LZ4_END+1
-	ram[LZ4_END+1]=a;	cycles+=3;	// sta     LZ4_END+1
+	ram[LZ4_END+1]=A;	cycles+=3;	// sta     LZ4_END+1
 
-	a=high(orgoff);		cycles+=2;	// lda     #>orgoff                ; original unpacked data offset
-        ram[LZ4_DST+1]=a;	cycles+=3;	// sta     LZ4_DST+1
-	a=low(orgoff);		cycles+=2;	// lda     #<orgoff
-	ram[LZ4_DST]=a;		cycles+=3;	// sta     LZ4_DST
+	A=high(orgoff);		cycles+=2;	// lda     #>orgoff                ; original unpacked data offset
+        ram[LZ4_DST+1]=A;	cycles+=3;	// sta     LZ4_DST+1
+	A=low(orgoff);		cycles+=2;	// lda     #<orgoff
+	ram[LZ4_DST]=A;		cycles+=3;	// sta     LZ4_DST
 
 //	printf("packed size: raw=%x, adj=%x\n",size,paksize);
 	printf("packed addr: %02X%02X\n",ram[LZ4_SRC+1],ram[LZ4_SRC]);
@@ -151,7 +151,7 @@ int lz4_decode(void) {
 	printf("dest addr  : %02X%02X\n",ram[LZ4_DST+1],ram[LZ4_DST]);
 
 //unpmain:
-	y=0;		cycles+=2;	// used for offset	//ldy	#0
+	Y=0;		cycles+=2;	// used for offset	//ldy	#0
 
 parsetoken:
 	getsrc();	cycles+=6;	// jsr	getsrc
@@ -162,22 +162,22 @@ parsetoken:
 	lsr();		cycles+=2;				// lsr
 	lsr();		cycles+=2;				// lsr
 	cycles+=2;
-	if (a==0) {
+	if (A==0) {
 		cycles+=1;
 		goto copymatches; 	// if zero, no literals // beq	copymatches
 	}
 
 	buildcount();	cycles+=6;	// otherwise, build the count // jsr	buildcount
 
-	x=a;			cycles+=2;	// tax
+	X=A;			cycles+=2;	// tax
 	docopy();		cycles+=6;	// jsr	docopy
-	a=ram[LZ4_SRC];		cycles+=3;	// lda	LZ4_SRC
+	A=ram[LZ4_SRC];		cycles+=3;	// lda	LZ4_SRC
 	cmp(ram[end]);		cycles+=3;	// cmp	end
-	a=ram[LZ4_SRC+1];	cycles+=3;	// lda	LZ4_SRC+1
+	A=ram[LZ4_SRC+1];	cycles+=3;	// lda	LZ4_SRC+1
 
 	sbc(ram[end+1]);	cycles+=3;	// sbc	end+1
 	cycles+=2;
-	if (c) {
+	if (C) {
 		printf("Done!\n");
 		printf("src        : %02X%02X\n",ram[LZ4_SRC+1],ram[LZ4_SRC]);
 		printf("packed end : %02X%02X\n",ram[end+1],ram[end]);
@@ -187,45 +187,45 @@ parsetoken:
 
 copymatches:
 	getsrc();		cycles+=6;	// jsr	getsrc
-	ram[DELTA]=a;		cycles+=3;	// sta	DELTA
+	ram[DELTA]=A;		cycles+=3;	// sta	DELTA
 	getsrc();		cycles+=6;	// jsr	getsrc
-	ram[DELTA+1]=a;		cycles+=3;	// sta	DELTA+1
+	ram[DELTA+1]=A;		cycles+=3;	// sta	DELTA+1
 	pla();			cycles+=3;	// restore token	// pla
-	a=a&0xf;		cycles+=2;	// get bottom 4 bits	// and	#$0f
+	A=A&0xf;		cycles+=2;	// get bottom 4 bits	// and	#$0f
 	buildcount();		cycles+=6;	// jsr	buildcount
 
-	c=0;			cycles+=2;	// clc
+	C=0;			cycles+=2;	// clc
 	adc(4);			cycles+=2;	// adc	#4
-	x=a;			cycles+=2;	// tax
+	X=A;			cycles+=2;	// tax
 	cycles+=2;
-	if (x==0) {
+	if (X==0) {
 		cycles+=1;
 		goto copy_skip;	//BUGFIX // beq  +
 	}
 	cycles+=2;
-	if (c==0) {
+	if (C==0) {
 		cycles+=1;
 		goto copy_skip;	// bcc	+
 	}
 	ram[COUNT+1]++;		cycles+=5;	// inc	count+1
 copy_skip:
-	a=ram[LZ4_SRC+1];	cycles+=3;	//+	lda	src+1
+	A=ram[LZ4_SRC+1];	cycles+=3;	//+	lda	src+1
 	pha();			cycles+=3;	// pha
-	a=ram[LZ4_SRC];		cycles+=3;	// lda	src
+	A=ram[LZ4_SRC];		cycles+=3;	// lda	src
 	pha();			cycles+=3;	// pha
-	c=1;			cycles+=2;	// sec
-	a=ram[LZ4_DST];		cycles+=3;	// lda	LZ4_DST
+	C=1;			cycles+=2;	// sec
+	A=ram[LZ4_DST];		cycles+=3;	// lda	LZ4_DST
 	sbc(ram[DELTA]);	cycles+=3;	// sbc	DELTA
-	ram[LZ4_SRC]=a;		cycles+=3;	// sta	LZ4_SRC
-	a=ram[LZ4_DST+1];	cycles+=3;	// lda	LZ4_DST+1
+	ram[LZ4_SRC]=A;		cycles+=3;	// sta	LZ4_SRC
+	A=ram[LZ4_DST+1];	cycles+=3;	// lda	LZ4_DST+1
 	sbc(ram[DELTA+1]);	cycles+=3;	// sbc	DELTA+1
-	ram[LZ4_SRC+1]=a;	cycles+=3;	// sta	LZ4_SRC+1
+	ram[LZ4_SRC+1]=A;	cycles+=3;	// sta	LZ4_SRC+1
 
 	docopy();		cycles+=6;	// jsr	docopy
 	pla();			cycles+=3;	// pla
-	ram[LZ4_SRC]=a;		cycles+=3;	// sta	LZ4_SRC
+	ram[LZ4_SRC]=A;		cycles+=3;	// sta	LZ4_SRC
 	pla();			cycles+=3;	// pla
-	ram[LZ4_SRC+1]=a;	cycles+=3;	// sta	LZ4_SRC+1
+	ram[LZ4_SRC+1]=A;	cycles+=3;	// sta	LZ4_SRC+1
 	cycles+=3;
 	goto parsetoken;		// jmp	parsetoken
 
@@ -262,13 +262,13 @@ static void print_both_pages(void) {
 
 	for(i=0;i<ram[CH];i++) printf(" ");
 
-	y=0;
+	Y=0;
 
 	while(1) {
-		a=ram[y_indirect(OUTL,y)];
-		if (a==0) break;
-		printf("%c",a);
-		y++;
+		A=ram[y_indirect(OUTL,Y)];
+		if (A==0) break;
+		printf("%c",A);
+		Y++;
 	}
 	printf("\n");
 }
@@ -276,20 +276,20 @@ static void print_both_pages(void) {
 
 static void print_header_info(void) {
 
-	ram[CV]=a;
+	ram[CV]=A;
 
-	y++;
-	a=y;
-	y=0;
-	c=0;
+	Y++;
+	A=Y;
+	Y=0;
+	C=0;
 	adc(ram[OUTL]);
-	ram[OUTL]=a;
-	a=ram[OUTH];
+	ram[OUTL]=A;
+	A=ram[OUTH];
 	adc(0);
-	ram[OUTH]=a;
+	ram[OUTH]=A;
 
-	a=ram[y_indirect(OUTL,y)];
-	ram[CH]=a;
+	A=ram[y_indirect(OUTL,Y)];
+	ram[CH]=A;
 
 	ram[OUTL]++;
 	if (ram[OUTL]==0) ram[OUTH]++;
@@ -321,55 +321,55 @@ int main(int argc, char **argv) {
 
 	memcpy(&ram[LZ4_BUFFER],input,size);
 
-	a=high(LZ4_BUFFER);
-	ram[OUTH]=a;
-	a=low(LZ4_BUFFER);
-	ram[OUTL]=a;
+	A=high(LZ4_BUFFER);
+	ram[OUTH]=A;
+	A=low(LZ4_BUFFER);
+	ram[OUTL]=A;
 
-	y=3;
+	Y=3;
 
-	a=20;
+	A=20;
 	print_header_info();
 
-	a=21;
+	A=21;
 	print_header_info();
 	printf("\n");
 
-	a=23;
+	A=23;
 	print_header_info();
 
-	y=0;
-	a=high(LZ4_BUFFER+3);
-	ram[LZ4_SRC+1]=a;
-	a=low(LZ4_BUFFER+3);
-	ram[LZ4_SRC]=a;
+	Y=0;
+	A=high(LZ4_BUFFER+3);
+	ram[LZ4_SRC+1]=A;
+	A=low(LZ4_BUFFER+3);
+	ram[LZ4_SRC]=A;
 
-	a=ram[y_indirect(LZ4_SRC,y)];
-	c=0;
+	A=ram[y_indirect(LZ4_SRC,Y)];
+	C=0;
 	adc(ram[LZ4_SRC]);
-	ram[LZ4_SRC]=a;
-	a=ram[LZ4_SRC+1];
+	ram[LZ4_SRC]=A;
+	A=ram[LZ4_SRC+1];
 	adc(0);
-	ram[LZ4_SRC+1]=a;
+	ram[LZ4_SRC+1]=A;
 
 // next_subsong:
 
-	y=0;
+	Y=0;
 
-	a=ram[y_indirect(LZ4_SRC,y)];
-	ram[LZ4_END]=a;
-	y++;
-	a=ram[y_indirect(LZ4_SRC,y)];
-	ram[LZ4_END+1]=a;
-	y++;
+	A=ram[y_indirect(LZ4_SRC,Y)];
+	ram[LZ4_END]=A;
+	Y++;
+	A=ram[y_indirect(LZ4_SRC,Y)];
+	ram[LZ4_END+1]=A;
+	Y++;
 
-	a=2;
-	c=0;
+	A=2;
+	C=0;
 	adc(ram[LZ4_SRC]);
-	ram[LZ4_SRC]=a;
-	a=(ram[LZ4_SRC+1]);
+	ram[LZ4_SRC]=A;
+	A=(ram[LZ4_SRC+1]);
 	adc(0);
-	ram[LZ4_SRC+1]=a;
+	ram[LZ4_SRC+1]=A;
 
 	lz4_decode();
 
diff --git a/utils/gr-sim/lz4/lz4d_verbose.c b/utils/gr-sim/lz4/lz4d_verbose.c
index 114cbdfc..24ec6390 100644
--- a/utils/gr-sim/lz4/lz4d_verbose.c
+++ b/utils/gr-sim/lz4/lz4d_verbose.c
@@ -20,9 +20,9 @@ static unsigned char input[MAX_INPUT];
 
 static void getsrc(void) {
 //getsrc:
-	a=ram[y_indirect(src,y)];		// lda 	(src), y
+	A=ram[y_indirect(src,Y)];		// lda 	(src), y
 
-	printf("LOAD %02X%02X: %02X\n",ram[src+1],ram[src],a);
+	printf("LOAD %02X%02X: %02X\n",ram[src+1],ram[src],A);
 
 	ram[src]++;				//inc	src
 	if (ram[src]!=0) goto done_getsrc;	//bne	+
@@ -33,39 +33,39 @@ done_getsrc: ;
 }
 
 void buildcount(void) {
-	printf("\tBUILDCOUNT: A=0x%x\n",a);
+	printf("\tBUILDCOUNT: A=0x%x\n",A);
 //buildcount:
-	x=1;					// ??		// ldx	#1
-	ram[count+1]=x; 			// ??		// stx	count+1
+	X=1;					// ??		// ldx	#1
+	ram[count+1]=X; 			// ??		// stx	count+1
 	cmp(0xf);				// if 15, more complicated // cmp	#$0f
-	if (z==0) goto done_buildcount;		// otherwise A is count // bne	++
+	if (Z==0) goto done_buildcount;		// otherwise A is count // bne	++
 buildcount_loop:
-	ram[count]=a;				//-	sta	count
+	ram[count]=A;				//-	sta	count
 //	printf("MBC ");
 	getsrc();				//jsr	getsrc
-	printf("\tADDITIONAL BUILDCOUNT 0x%x, adding 0x%x\n",a,ram[count]);
-	x=a;					//tax
-	c=0;					//clc
+	printf("\tADDITIONAL BUILDCOUNT 0x%x, adding 0x%x\n",A,ram[count]);
+	X=A;					//tax
+	C=0;					//clc
 	adc(ram[count]);			//adc	count
-	printf("\tGOT 0x%x c=%d\n",a,c);
-	if (c==0) goto skip_buildcount;		// bcc	+
+	printf("\tGOT 0x%x c=%d\n",A,C);
+	if (C==0) goto skip_buildcount;		// bcc	+
 	ram[count+1]++;				//inc	count+1
 skip_buildcount:
-	printf("\tUPDATED COUNT %02X%02X\n",ram[count+1],a);
-	x++;					// check if x is 255	//+	inx
-	if (x==0) goto buildcount_loop;		// if so, add in next byte //beq	-
+	printf("\tUPDATED COUNT %02X%02X\n",ram[count+1],A);
+	X++;					// check if x is 255	//+	inx
+	if (X==0) goto buildcount_loop;		// if so, add in next byte //beq	-
 done_buildcount: ;				//++	rts
 	printf("\tBUILDCOUNT= %02X%02X r[c+1]=%02X r[c]=%02X a=%02X x=%02X\n",
-		ram[count+1],a,ram[count+1],ram[count],a,x);
+		ram[count+1],A,ram[count+1],ram[count],A,X);
 }
 
 
 static void putdst(void) {
 //	printf("PUTADDR=%04X\n",y_indirect(dst,y));
 						// putdst:
-	ram[y_indirect(dst,y)]=a;		//	sta 	(dst), y
-	if (y!=0) printf("ERROR ERROR ERROR ERROR ERROR\n");
-	printf("\t\tPUT: %02X%02X = %02X\n",ram[dst+1],ram[dst],a);
+	ram[y_indirect(dst,Y)]=A;		//	sta 	(dst), y
+	if (Y!=0) printf("ERROR ERROR ERROR ERROR ERROR\n");
+	printf("\t\tPUT: %02X%02X = %02X\n",ram[dst+1],ram[dst],A);
 	ram[dst]++;				//	inc	dst
 	if (ram[dst]!=0) goto putdst_end;	//	bne	+
 	ram[dst+1]++;				//	inc	dst+1
@@ -87,13 +87,13 @@ static void getput(void) {
 // 1ff -> 1fe
 
 static void docopy(void) {
-	printf("\tDOCOPY ENTRY: %02X%02X\n",ram[count+1],x);
+	printf("\tDOCOPY ENTRY: %02X%02X\n",ram[count+1],X);
 						// docopy:
 docopy_label:
-	printf("\tDOCOPY %02X%02X: ",ram[count+1],x);
+	printf("\tDOCOPY %02X%02X: ",ram[count+1],X);
 	getput();				// jsr	getput
-	x--;					// dex
-	if (x!=0) goto docopy_label;		// bne	docopy
+	X--;					// dex
+	if (X!=0) goto docopy_label;		// bne	docopy
 	ram[count+1]--;				// dec	count+1
 	if (ram[count+1]!=0) goto docopy_label;	//bne	docopy
 						//rts
@@ -152,18 +152,18 @@ int main(int argc, char **argv) {
 //LCBANK2	=	$c083
 //MOVE	=	$fe2c
 
-	a=(pakoff&0xff);	//lda	#<pakoff ;packed data offset
-	ram[src]=a;		//sta	src
-	a=(pakoff+paksize)&0xff;//lda	#<(pakoff+paksize) ;packed data size
-	ram[end]=a;		// sta	end
-	a=(pakoff>>8);		//lda	#>pakoff
-	ram[src+1]=a;		//sta	src+1
-	a=(pakoff+paksize)>>8;	//lda	#>(pakoff+paksize)
-	ram[end+1]=a;		//	sta	end+1
-	a=(orgoff>>8);		//lda	#>orgoff ;original unpacked data offset
-	ram[dst+1]=a;		//sta	dst+1
-	a=(orgoff&0xff);	//lda	#<orgoff
-	ram[dst]=a;		// sta	dst
+	A=(pakoff&0xff);	//lda	#<pakoff ;packed data offset
+	ram[src]=A;		//sta	src
+	A=(pakoff+paksize)&0xff;//lda	#<(pakoff+paksize) ;packed data size
+	ram[end]=A;		// sta	end
+	A=(pakoff>>8);		//lda	#>pakoff
+	ram[src+1]=A;		//sta	src+1
+	A=(pakoff+paksize)>>8;	//lda	#>(pakoff+paksize)
+	ram[end+1]=A;		//	sta	end+1
+	A=(orgoff>>8);		//lda	#>orgoff ;original unpacked data offset
+	ram[dst+1]=A;		//sta	dst+1
+	A=(orgoff&0xff);	//lda	#<orgoff
+	ram[dst]=A;		// sta	dst
 
 	printf("packed size: raw=%x, adj=%x\n",size,paksize);
 	printf("packed addr: %02X%02X\n",ram[src+1],ram[src]);
@@ -184,7 +184,7 @@ int main(int argc, char **argv) {
 //	goto unpmain;			// jmp	unpmain
 
 //unpack:
-	y=0;				// used for offset	//ldy	#0
+	Y=0;				// used for offset	//ldy	#0
 
 parsetoken:
 	token_count++;
@@ -196,18 +196,18 @@ parsetoken:
 	lsr();							// lsr
 	lsr();							// lsr
 	lsr();							// lsr
-	if (a==0) goto copymatches; 	// if zero, no literals // beq	copymatches
+	if (A==0) goto copymatches; 	// if zero, no literals // beq	copymatches
 
 	buildcount();			// otherwise, build the count // jsr	buildcount
 
-	x=a;				// tax
+	X=A;				// tax
 	docopy();			// jsr	docopy
-	a=ram[src];			// lda	src
+	A=ram[src];			// lda	src
 	cmp(ram[end]);			// cmp	end
-	a=ram[src+1];			// lda	src+1
+	A=ram[src+1];			// lda	src+1
 
 	sbc(ram[end+1]);		// sbc	end+1
-	if (c) {
+	if (C) {
 		printf("Done!\n");
 		printf("src        : %02X%02X\n",ram[src+1],ram[src]);
 		printf("packed end : %02X%02X\n",ram[end+1],ram[end]);
@@ -217,41 +217,41 @@ parsetoken:
 copymatches:
 	printf("\tDELTAL ");
 	getsrc();					// jsr	getsrc
-	ram[delta]=a;					// sta	delta
+	ram[delta]=A;					// sta	delta
 	printf("\tDELTAH ");
 	getsrc();					// jsr	getsrc
-	ram[delta+1]=a;					// sta	delta+1
+	ram[delta+1]=A;					// sta	delta+1
 	printf("\tDELTA is %02X%02X\n",ram[delta+1],ram[delta]);
 	pla();				// restore token	// pla
-	a=a&0xf;			// get bottom 4 bits	// and	#$0f
+	A=A&0xf;			// get bottom 4 bits	// and	#$0f
 	buildcount();			// jsr	buildcount
 
-	c=0;				// clc
+	C=0;				// clc
 	adc(4);				// adc	#4
-	x=a;				// tax
-	if (x==0) goto copy_skip;	//BUGFIX // beq  +
-	if (c==0) goto copy_skip;	// bcc	+
+	X=A;				// tax
+	if (X==0) goto copy_skip;	//BUGFIX // beq  +
+	if (C==0) goto copy_skip;	// bcc	+
 	ram[count+1]++;			// inc	count+1
 copy_skip:
-	a=ram[src+1];			//+	lda	src+1
+	A=ram[src+1];			//+	lda	src+1
 	pha();				// pha
-	a=ram[src];			// lda	src
+	A=ram[src];			// lda	src
 	pha();				// pha
 	printf("\tSAVED SRC: %02X%02X\n",ram[src+1],ram[src]);
 //	printf("CALCULATING: DST %02X%02X - DELTA %02X%02X\n",ram[dst+1],ram[dst],ram[delta+1],ram[delta]);
-	c=1;				// sec
-	a=ram[dst];			// lda	dst
+	C=1;				// sec
+	A=ram[dst];			// lda	dst
 	sbc(ram[delta]);		// sbc	delta
-	ram[src]=a;			// sta	src
-	a=ram[dst+1];			// lda	dst+1
+	ram[src]=A;			// sta	src
+	A=ram[dst+1];			// lda	dst+1
 	sbc(ram[delta+1]);		// sbc	delta+1
-	ram[src+1]=a;			// sta	src+1
+	ram[src+1]=A;			// sta	src+1
 	printf("\tNEW SRC: %02X%02X\n",ram[src+1],ram[src]);
 	docopy();			// jsr	docopy
 	pla();				// pla
-	ram[src]=a;			// sta	src
+	ram[src]=A;			// sta	src
 	pla();				// pla
-	ram[src+1]=a;			// sta	src+1
+	ram[src+1]=A;			// sta	src+1
 	printf("\tRESTORED SRC: %02X%02X\n",ram[src+1],ram[src]);
 	goto parsetoken;		// jmp	parsetoken
 
diff --git a/utils/gr-sim/tfv/tfv_flying_6502.c b/utils/gr-sim/tfv/tfv_flying_6502.c
index 0e7300ef..fcac8033 100644
--- a/utils/gr-sim/tfv/tfv_flying_6502.c
+++ b/utils/gr-sim/tfv/tfv_flying_6502.c
@@ -686,14 +686,14 @@ static void draw_background_mode7(void) {
 
 	do {
 //screeny_loop:
-		y=0;
+		Y=0;
 
 		/* actual code does even/odd stuff here */
 
 							cycles.mode7+=27;
 //setup_gr_addr:
 
-		hlin_setup(ram[DRAW_PAGE],y,0,ram[SCREEN_Y]);
+		hlin_setup(ram[DRAW_PAGE],Y,0,ram[SCREEN_Y]);
 							cycles.mode7+=21;
 
 //calc_horizontal_scale:
@@ -836,14 +836,14 @@ match:
 			ram[COLOR]=(map_color&0xf);
 //			ram[COLOR]|=map_color<<4;
 
-			y=0;
+			Y=0;
 			if ((ram[SCREEN_Y]&1)==0) {
-				ram[y_indirect(GBASL,y)]=ram[COLOR];
+				ram[y_indirect(GBASL,Y)]=ram[COLOR];
 							cycles.mode7+=18;
 			}
 			else {
-				a=ram[COLOR];
-				ram[y_indirect(GBASL,y)]|=(a<<4);
+				A=ram[COLOR];
+				ram[y_indirect(GBASL,Y)]|=(A<<4);
 							cycles.mode7+=22;
 
 			}
diff --git a/utils/gr-sim/tfv_utils.c b/utils/gr-sim/tfv_utils.c
index b1d7d744..ee421c5d 100644
--- a/utils/gr-sim/tfv_utils.c
+++ b/utils/gr-sim/tfv_utils.c
@@ -59,14 +59,14 @@ int select_menu(int x, int y, int num, char **items) {
 
 void apple_memset(unsigned char *ptr, int value, int length) {
 
-	a=value;
-	x=length;
-	y=0;
+	A=value;
+	X=length;
+	Y=0;
 
-	while(x>0) {
-		ptr[y]=a;
-		y++;
-		x--;
+	while(X>0) {
+		ptr[Y]=A;
+		Y++;
+		X--;
 	}
 }
 
diff --git a/utils/gr-sim/twister/Makefile b/utils/gr-sim/twister/Makefile
index 7b68b9a0..03670f2b 100644
--- a/utils/gr-sim/twister/Makefile
+++ b/utils/gr-sim/twister/Makefile
@@ -37,4 +37,4 @@ twist_dump.o:	twist_dump.c
 ###
 
 clean:	
-	rm -f *~ *.o twist_6502 twist_dump
+	rm -f *~ *.o twist_6502 twist_dump generate_sines