diff --git a/src/devices/cpu/unsp/unsp_extended.cpp b/src/devices/cpu/unsp/unsp_extended.cpp
index b1cd206a626..948255ff610 100644
--- a/src/devices/cpu/unsp/unsp_extended.cpp
+++ b/src/devices/cpu/unsp/unsp_extended.cpp
@@ -240,7 +240,7 @@ void unsp_20_device::execute_extended_group(uint16_t op)
 				if (aluop != 0x0d)
 					r1 = read16(r2);
 				m_core->m_r[ry] = (uint16_t)(m_core->m_r[ry] - 1);
-				if (m_core->m_r[ry] == 0xffff)
+				if (m_core->m_r[ry] == 0xffff && use_ds)
 					m_core->m_r[REG_SR] -= 0x0400;
 				break;
 			case 0x2: // Rx, [<ds:>Ry++]
@@ -248,7 +248,7 @@ void unsp_20_device::execute_extended_group(uint16_t op)
 				if (aluop != 0x0d)
 					r1 = read16(r2);
 				m_core->m_r[ry] = (uint16_t)(m_core->m_r[ry] + 1);
-				if (m_core->m_r[ry] == 0x0000)
+				if (m_core->m_r[ry] == 0x0000 && use_ds)
 					m_core->m_r[REG_SR] += 0x0400;
 				break;
 			case 0x3: // Rx, [<ds:>++Ry]
diff --git a/src/devices/cpu/unsp/unsp_exxx.cpp b/src/devices/cpu/unsp/unsp_exxx.cpp
index 07e8f056984..06ccd2e11f5 100644
--- a/src/devices/cpu/unsp/unsp_exxx.cpp
+++ b/src/devices/cpu/unsp/unsp_exxx.cpp
@@ -83,7 +83,7 @@ void unsp_12_device::execute_exxx_group(uint16_t op)
 		const uint16_t addr =  m_core->m_r[rd];
 		const uint16_t orig =  read16(addr);
 		m_core->m_r[REG_SR] &= ~UNSP_Z;
-		m_core->m_r[REG_SR] |= BIT(m_core->m_r[rd], offset) ? 0 : UNSP_Z;
+		m_core->m_r[REG_SR] |= BIT(orig, offset) ? 0 : UNSP_Z;
 
 		switch (bitop)
 		{
@@ -113,7 +113,7 @@ void unsp_12_device::execute_exxx_group(uint16_t op)
 		const uint32_t addr =  m_core->m_r[rd] | (get_ds() << 16);
 		const uint16_t orig =  read16(addr);
 		m_core->m_r[REG_SR] &= ~UNSP_Z;
-		m_core->m_r[REG_SR] |= BIT(m_core->m_r[rd], offset) ? 0 : UNSP_Z;
+		m_core->m_r[REG_SR] |= BIT(orig, offset) ? 0 : UNSP_Z;
 
 		switch (bitop)
 		{
@@ -140,11 +140,11 @@ void unsp_12_device::execute_exxx_group(uint16_t op)
 		const uint8_t bitop =  (op & 0x0030) >> 4;
 		const uint8_t rd =     (op & 0x0e00) >> 9;
 		const uint8_t rs =     (op & 0x0007) >> 0;
-		const uint8_t offset = (1 << m_core->m_r[rs]);
+		const uint8_t offset = (1 << (m_core->m_r[rs] & 0xf));
 		const uint16_t addr =  m_core->m_r[rd];
 		const uint16_t orig =  read16(addr);
 		m_core->m_r[REG_SR] &= ~UNSP_Z;
-		m_core->m_r[REG_SR] |= BIT(m_core->m_r[rd], offset) ? 0 : UNSP_Z;
+		m_core->m_r[REG_SR] |= BIT(orig, offset) ? 0 : UNSP_Z;
 
 		switch (bitop)
 		{
diff --git a/src/devices/cpu/unsp/unsp_fxxx.cpp b/src/devices/cpu/unsp/unsp_fxxx.cpp
index 638f8d27387..fabec7a8d70 100644
--- a/src/devices/cpu/unsp/unsp_fxxx.cpp
+++ b/src/devices/cpu/unsp/unsp_fxxx.cpp
@@ -250,7 +250,6 @@ inline void unsp_device::execute_fxxx_100_group(uint16_t op)
 
 void unsp_12_device::execute_divq(uint16_t op)
 {
-	uint32_t orig_dividend = 0;
 	if (m_core->m_divq_bit == UINT_MAX)
 	{
 		m_core->m_divq_bit = 15;
@@ -258,7 +257,6 @@ void unsp_12_device::execute_divq(uint16_t op)
 		m_core->m_divq_divisor = m_core->m_r[REG_R2];
 		m_core->m_divq_a = 0;
 	}
-	orig_dividend = m_core->m_divq_dividend;
 	m_core->m_aq = BIT(m_core->m_divq_a, 31);
 	if (m_core->m_aq)
 	{