diff --git a/src/emu/cpu/m6502/m740.c b/src/emu/cpu/m6502/m740.c
index 4619dbc313d..bb12b29f84a 100644
--- a/src/emu/cpu/m6502/m740.c
+++ b/src/emu/cpu/m6502/m740.c
@@ -113,7 +113,6 @@ void m740_device::do_sbc_dt(UINT8 val)
 {
 	UINT8 c = P & F_C ? 0 : 1;
 	P &= ~(F_N|F_V|F_Z|F_C);
-	TMP2 = read(X);
 	UINT16 diff = TMP2 - val - c;
 	UINT8 al = (TMP2 & 15) - (val & 15) - c;
 	if(INT8(al) < 0)
@@ -130,15 +129,11 @@ void m740_device::do_sbc_dt(UINT8 val)
 	if(INT8(ah) < 0)
 		ah -= 6;
 	TMP2 = (ah << 4) | (al & 15);
-	write(X, TMP2);
 }
 
 void m740_device::do_sbc_ndt(UINT8 val)
 {
-	UINT16 diff;
-
-	TMP2 = read(X);
-	diff = TMP2 - val - (P & F_C ? 0 : 1);
+	UINT16 diff = TMP2 - val - (P & F_C ? 0 : 1);
 	P &= ~(F_N|F_V|F_Z|F_C);
 	if(!UINT8(diff))
 		P |= F_Z;
@@ -149,7 +144,6 @@ void m740_device::do_sbc_ndt(UINT8 val)
 	if(!(diff & 0xff00))
 		P |= F_C;
 	TMP2 = diff;
-	write(X, TMP2);
 }
 
 void m740_device::do_sbct(UINT8 val)
@@ -164,7 +158,6 @@ void m740_device::do_adc_dt(UINT8 val)
 {
 	UINT8 c = P & F_C ? 1 : 0;
 	P &= ~(F_N|F_V|F_Z|F_C);
-	TMP2 = read(X);
 	UINT8 al = (TMP2 & 15) + (val & 15) + c;
 	if(al > 9)
 		al += 6;
@@ -180,13 +173,11 @@ void m740_device::do_adc_dt(UINT8 val)
 	if(ah > 15)
 		P |= F_C;
 	TMP2 = (ah << 4) | (al & 15);
-	write(X, TMP2);
 }
 
 void m740_device::do_adc_ndt(UINT8 val)
 {
 	UINT16 sum;
-	TMP2 = read(X);
 	sum = TMP2 + val + (P & F_C ? 1 : 0);
 	P &= ~(F_N|F_V|F_Z|F_C);
 	if(!UINT8(sum))
@@ -198,7 +189,6 @@ void m740_device::do_adc_ndt(UINT8 val)
 	if(sum & 0xff00)
 		P |= F_C;
 	TMP2 = sum;
-	write(X, TMP2);
 }
 
 void m740_device::do_adct(UINT8 val)
diff --git a/src/emu/cpu/m6502/om740.lst b/src/emu/cpu/m6502/om740.lst
index 4c3821a25bf..70a2b52ddbe 100644
--- a/src/emu/cpu/m6502/om740.lst
+++ b/src/emu/cpu/m6502/om740.lst
@@ -152,7 +152,9 @@ adct_aba
 	TMP = read_pc();
 	TMP = set_h(TMP, read_pc());
 	TMP = read(TMP);
+	TMP2 = read(X);
 	do_adct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 adct_abx
@@ -163,7 +165,9 @@ adct_abx
 	}
 	TMP += X;
 	TMP = read(TMP);
+	TMP2 = read(X);
 	do_adct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 adct_aby
@@ -174,7 +178,9 @@ adct_aby
 	}
 	TMP += Y;
 	TMP = read(TMP);
+	TMP2 = read(X);
 	do_adct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 adct_idx
@@ -183,7 +189,9 @@ adct_idx
 	TMP2 += X;
 	TMP = read(TMP2 & 0xff);
 	TMP = set_h(TMP, read((TMP2+1) & 0xff));
+	TMP2 = read(X);
 	do_adct(read(TMP));
+	write(X, TMP2);
 	prefetch();
 
 adct_idy
@@ -193,25 +201,33 @@ adct_idy
 	if(page_changing(TMP, Y)) {
 		read(set_l(TMP, TMP+Y));
 	}
+	TMP2 = read(X);
 	do_adct(read(TMP+Y));
+	write(X, TMP2);
 	prefetch();
 
 adct_imm
 	TMP = read_pc();
+	TMP2 = read(X);
 	do_adct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 adct_zpg
 	TMP = read_pc();
 	TMP = read(TMP);
+	TMP2 = read(X);
 	do_adct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 adct_zpx
 	TMP = read_pc();
 	read(TMP);
 	TMP = read(UINT8(TMP+X));
+	TMP2 = read(X);
 	do_adct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 andt_aba
@@ -654,7 +670,9 @@ sbct_aba
 	TMP = read_pc();
 	TMP = set_h(TMP, read_pc());
 	TMP = read(TMP);
+	TMP2 = read(X);
 	do_sbct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 sbct_abx
@@ -665,7 +683,9 @@ sbct_abx
 	}
 	TMP += X;
 	TMP = read(TMP);
+	TMP2 = read(X);
 	do_sbct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 sbct_aby
@@ -676,7 +696,9 @@ sbct_aby
 	}
 	TMP += Y;
 	TMP = read(TMP);
+	TMP2 = read(X);
 	do_sbct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 sbct_idx
@@ -685,7 +707,9 @@ sbct_idx
 	TMP2 += X;
 	TMP = read(TMP2 & 0xff);
 	TMP = set_h(TMP, read((TMP2+1) & 0xff));
+	TMP2 = read(X);
 	do_sbct(read(TMP));
+	write(X, TMP2);
 	prefetch();
 
 sbct_idy
@@ -695,24 +719,32 @@ sbct_idy
 	if(page_changing(TMP, Y)) {
 		read(set_l(TMP, TMP+Y));
 	}
+	TMP2 = read(X);
 	do_sbct(read(TMP+Y));
+	write(X, TMP2);
 	prefetch();
 
 sbct_imm
 	TMP = read_pc();
+	TMP2 = read(X);
 	do_sbct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 sbct_zpg
 	TMP = read_pc();
 	TMP = read(TMP);
+	TMP2 = read(X);
 	do_sbct(TMP);
+	write(X, TMP2);
 	prefetch();
 
 sbct_zpx
 	TMP = read_pc();
 	read(TMP);
 	TMP = read(UINT8(TMP+X));
+	TMP2 = read(X);
 	do_sbct(TMP);
+	write(X, TMP2);
 	prefetch();