diff --git a/src/devices/machine/hdc92x4.cpp b/src/devices/machine/hdc92x4.cpp
index cda79df1137..0b92ed0a4c4 100644
--- a/src/devices/machine/hdc92x4.cpp
+++ b/src/devices/machine/hdc92x4.cpp
@@ -1746,9 +1746,9 @@ void hdc92x4_device::seek_read_id()
 	}
 
 	int cont = NEXT;
-	bool step_enable = (current_command() & 0x04)==1;
-	bool wait_seek_comp = (current_command() & 0x02)==1;
-	bool do_verify = (current_command() & 0x01)==1;
+	bool step_enable = BIT(current_command(), 2);
+	bool wait_seek_comp = BIT(current_command(), 1);
+	bool do_verify = BIT(current_command(), 0);
 	m_logical = true;
 
 	while (cont == NEXT)
diff --git a/src/devices/machine/roc10937.cpp b/src/devices/machine/roc10937.cpp
index 3be5f16a2a1..2573e9549b0 100644
--- a/src/devices/machine/roc10937.cpp
+++ b/src/devices/machine/roc10937.cpp
@@ -361,8 +361,8 @@ void roc10957_t::write_char(int data)
 		}
 	}
 	else
-	{ // Display data
-		data &= 0x3F;
+	{ // Display data.  Bit 6 is a "don't care" bit except for PNT and TAIL.
+		data &= 0x7F;
 
 		switch ( data )
 		{
diff --git a/src/lib/formats/cbm_tap.cpp b/src/lib/formats/cbm_tap.cpp
index 0b0950eebcc..2699ab51ec0 100644
--- a/src/lib/formats/cbm_tap.cpp
+++ b/src/lib/formats/cbm_tap.cpp
@@ -173,9 +173,7 @@ static int cbm_tap_do_work( int16_t **buffer, int length, const uint8_t *data )
 	int i, j = 0;
 	int size = 0;
 
-	int version = data[0x0c];
-	int system = data[0x0d];
-	int video_standard = data[0x0e];
+	int version, system, video_standard;
 	int tap_frequency = 0;
 
 	int byte_samples = 0;
@@ -186,6 +184,14 @@ static int cbm_tap_do_work( int16_t **buffer, int length, const uint8_t *data )
 	  in Commodore tapes. Implementation here would follow */
 	/* int waveamp_high, waveamp_low; */
 
+	/* is the .tap file corrupted? */
+	if ((data == nullptr) || (length <= CBM_HEADER_SIZE))
+		return -1;
+
+	version = data[0x0c];
+	system = data[0x0d];
+	video_standard = data[0x0e];
+
 	/* Log .TAP info but only once */
 	if (!(buffer == nullptr))
 	{
@@ -203,10 +209,6 @@ static int cbm_tap_do_work( int16_t **buffer, int length, const uint8_t *data )
 		return -1;
 	}
 
-	/* is the .tap file corrupted? */
-	if ((data == nullptr) || (length <= CBM_HEADER_SIZE))
-		return -1;
-
 
 	/* read the frequency from the .tap header */
 	switch (system)
diff --git a/src/mame/drivers/argo.cpp b/src/mame/drivers/argo.cpp
index 26658e884d0..97e535fe435 100644
--- a/src/mame/drivers/argo.cpp
+++ b/src/mame/drivers/argo.cpp
@@ -114,7 +114,7 @@ WRITE8_MEMBER(argo_state::argo_io_w)
 		{
 			uint8_t *RAM = memregion("videoram")->base();
 			m_scroll_ctrl = 0;
-			memcpy(RAM, RAM+80, 24*80);
+			memmove(RAM, RAM+80, 24*80);
 		}
 		break;
 
diff --git a/src/mame/drivers/pc88va.cpp b/src/mame/drivers/pc88va.cpp
index 50ddb757152..e59c01fc642 100644
--- a/src/mame/drivers/pc88va.cpp
+++ b/src/mame/drivers/pc88va.cpp
@@ -176,7 +176,7 @@ DECLARE_WRITE8_MEMBER(dma_memw_cb);
 	void draw_sprites(bitmap_rgb32 &bitmap, const rectangle &cliprect);
 	uint32_t calc_kanji_rom_addr(uint8_t jis1,uint8_t jis2,int x,int y);
 	void draw_text(bitmap_rgb32 &bitmap, const rectangle &cliprect);
-	void tsp_sprite_enable(uint32_t spr_offset, uint8_t sw_bit);
+	void tsp_sprite_enable(uint32_t spr_offset, uint16_t sw_bit);
 	void execute_sync_cmd();
 	void execute_dspon_cmd();
 	void execute_dspdef_cmd();
@@ -759,7 +759,7 @@ WRITE8_MEMBER(pc88va_state::idp_command_w)
 	}
 }
 
-void pc88va_state::tsp_sprite_enable(uint32_t spr_offset, uint8_t sw_bit)
+void pc88va_state::tsp_sprite_enable(uint32_t spr_offset, uint16_t sw_bit)
 {
 	address_space &space = m_maincpu->space(AS_PROGRAM);
 
diff --git a/src/mame/drivers/peplus.cpp b/src/mame/drivers/peplus.cpp
index 3dd638353cf..d8c7511772c 100644
--- a/src/mame/drivers/peplus.cpp
+++ b/src/mame/drivers/peplus.cpp
@@ -795,7 +795,7 @@ READ8_MEMBER(peplus_state::peplus_input0_r)
 	}
 
 	if (m_bv_pulse == 1) {
-		return (0x70 || m_in0->read()); // Add Bill Validator Credit Pulse
+		return (0x70 | m_in0->read()); // Add Bill Validator Credit Pulse
 	} else {
 		return m_in0->read();
 	}
diff --git a/src/mame/drivers/unior.cpp b/src/mame/drivers/unior.cpp
index 00fbd9cdb72..cc32d924c4a 100644
--- a/src/mame/drivers/unior.cpp
+++ b/src/mame/drivers/unior.cpp
@@ -257,7 +257,7 @@ WRITE8_MEMBER( unior_state::vram_w )
 WRITE8_MEMBER( unior_state::scroll_w )
 {
 	if (data)
-		memcpy(m_p_vram, m_p_vram+80, 24*80);
+		memmove(m_p_vram, m_p_vram+80, 24*80);
 }
 
 I8275_DRAW_CHARACTER_MEMBER(unior_state::display_pixels)
diff --git a/src/mame/drivers/x07.cpp b/src/mame/drivers/x07.cpp
index c4a2a292132..598390b32af 100644
--- a/src/mame/drivers/x07.cpp
+++ b/src/mame/drivers/x07.cpp
@@ -1009,7 +1009,7 @@ void x07_state::kb_irq()
 	{
 		m_regs_r[0] = 0;
 		m_regs_r[1] = m_t6834_ram[0x400];
-		memcpy(m_t6834_ram + 0x400, m_t6834_ram + 0x401, 0xff);
+		memmove(m_t6834_ram + 0x400, m_t6834_ram + 0x401, 0xff);
 		m_kb_size--;
 		m_regs_r[2] |= 0x01;
 		m_maincpu->set_input_line(NSC800_RSTA, ASSERT_LINE);