diff --git a/ESP32/console_esp32.cpp b/ESP32/console_esp32.cpp
index 133a2c5..675d7b9 100644
--- a/ESP32/console_esp32.cpp
+++ b/ESP32/console_esp32.cpp
@@ -119,10 +119,10 @@ void console_esp32::panel_update_thread()
 			pixels.setPixelColor(b, full_addr & (1 << b) ? led_color : 0);
 
 		for(uint8_t b=0; b<16; b++)
-			pixels.setPixelColor(b + 22, current_PSW & (1 << b) ? magenta : 0);
+			pixels.setPixelColor(b + 22, current_PSW & (1l << b) ? magenta : 0);
 
 		for(uint8_t b=0; b<16; b++)
-			pixels.setPixelColor(b + 38, current_instr & (1 << b) ? red : 0);
+			pixels.setPixelColor(b + 38, current_instr & (1l << b) ? red : 0);
 
 		pixels.setPixelColor(54, running_flag             ? white : 0);
 
diff --git a/bus.cpp b/bus.cpp
index 538c23d..0026ad3 100644
--- a/bus.cpp
+++ b/bus.cpp
@@ -25,7 +25,7 @@ constexpr const int di_ena_mask[4] = { 4, 2, 0, 1 };
 
 bus::bus()
 {
-	m = new memory(n_pages * 8192);
+	m = new memory(n_pages * 8192l);
 
 	memset(pages, 0x00, sizeof pages);
 
@@ -372,7 +372,7 @@ uint16_t bus::read(const uint16_t addr_in, const word_mode_t word_mode, const rm
 		}
 
 		// LO size register field must be all 1s, so subtract 1
-		constexpr uint32_t system_size = n_pages * 8192 / 64 - 1;
+		constexpr uint32_t system_size = n_pages * 8192l / 64 - 1;
 
 		if (a == ADDR_SYSSIZE + 2) {  // system size HI
 			uint16_t temp = system_size >> 16;
@@ -416,12 +416,12 @@ uint16_t bus::read(const uint16_t addr_in, const word_mode_t word_mode, const rm
 	return temp;
 }
 
-void bus::setMMR0(const uint16_t value)
+void bus::setMMR0(uint16_t value)
 {
 	value &= ~(3 << 10);  // bit 10 & 11 always read as 0
 
 	if (value & 1)
-		value &= ~(7 << 13);  // reset error bits
+		value &= ~(7l << 13);  // reset error bits
 
 	if (MMR0 & 0160000) {
 		if ((value & 1) == 0)
@@ -543,13 +543,13 @@ uint32_t bus::calculate_physical_address(const int run_mode, const uint16_t a, c
 						pages[run_mode][d][apf].pdr |= 1 << 7;
 
 					if ((MMR0 & 0160000) == 0) {
-						MMR0 &= ~((1 << 15) | (1 << 14) | (1 << 13) | (1 << 12) | (3 << 5) | (7 << 1));
+						MMR0 &= ~((1l << 15) | (1 << 14) | (1 << 13) | (1 << 12) | (3 << 5) | (7 << 1));
 
 						if (is_write && access_control != 6)
 							MMR0 |= 1 << 13;  // read-only
 								  //
 						if (access_control == 0 || access_control == 4)
-							MMR0 |= 1 << 15;  // not resident
+							MMR0 |= 1l << 15;  // not resident
 						else
 							MMR0 |= 1 << 13;  // read-only
 
@@ -570,13 +570,13 @@ uint32_t bus::calculate_physical_address(const int run_mode, const uint16_t a, c
 				}
 			}
 
-			if (m_offset >= n_pages * 8192 && !is_io) {
-				DOLOG(debug, !peek_only, "bus::calculate_physical_address %o >= %o", m_offset, n_pages * 8192);
+			if (m_offset >= n_pages * 8192l && !is_io) {
+				DOLOG(debug, !peek_only, "bus::calculate_physical_address %o >= %o", m_offset, n_pages * 8192l);
 				DOLOG(debug, true, "TRAP(04) (throw 6) on address %06o", a);
 
 				if ((MMR0 & 0160000) == 0) {
 					MMR0 &= 017777;
-					MMR0 |= 1 << 15;  // non-resident
+					MMR0 |= 1l << 15;  // non-resident
 
 					MMR0 &= ~14;  // add current page
 					MMR0 |= apf << 1;
@@ -981,7 +981,7 @@ void bus::writePhysical(const uint32_t a, const uint16_t value)
 {
 	DOLOG(debug, true, "physicalWRITE %06o to %o", value, a);
 
-	if (a >= n_pages * 8192) {
+	if (a >= n_pages * 8192l) {
 		DOLOG(debug, true, "physicalWRITE to %o: trap 004", a);
 		c->trap(004);
 		throw 12;
@@ -993,7 +993,7 @@ void bus::writePhysical(const uint32_t a, const uint16_t value)
 
 uint16_t bus::readPhysical(const uint32_t a)
 {
-	if (a >= n_pages * 8192) {
+	if (a >= n_pages * 8192l) {
 		DOLOG(debug, true, "physicalREAD from %o: trap 004", a);
 		c->trap(004);
 		throw 13;
diff --git a/bus.h b/bus.h
index 153edef..dc17407 100644
--- a/bus.h
+++ b/bus.h
@@ -159,7 +159,7 @@ public:
 	void     setMMR0(const uint16_t value);
 	void     setMMR0Bit(const int bit);
 	void     clearMMR0Bit(const int bit);
-	void     setMMR2(const uint16_t value);
+	void     setMMR2(uint16_t value);
 
 	void     check_odd_addressing(const uint16_t a, const int run_mode, const d_i_space_t space, const bool is_write);
 	void     trap_odd(const uint16_t a);
diff --git a/cpu.cpp b/cpu.cpp
index 28f1852..02c4bfe 100644
--- a/cpu.cpp
+++ b/cpu.cpp
@@ -578,7 +578,7 @@ bool cpu::additional_double_operand_instructions(const uint16_t instr)
 					return true;
 				}
 
-				int32_t R0R1    = (getRegister(reg) << 16) | getRegister(reg | 1);
+				int32_t R0R1    = (uint32_t(getRegister(reg)) << 16) | getRegister(reg | 1);
 
 				int32_t  quot   = R0R1 / divider;
 				uint16_t rem    = R0R1 % divider;
@@ -657,7 +657,7 @@ bool cpu::additional_double_operand_instructions(const uint16_t instr)
 			}
 
 		case 3: { // ASHC
-				uint32_t R0R1  = (getRegister(reg) << 16) | getRegister(reg | 1);
+				uint32_t R0R1  = (uint32_t(getRegister(reg)) << 16) | getRegister(reg | 1);
 
 			        auto     g_dst = getGAM(dst_mode, dst_reg, wm_word, rm_cur);
 				uint16_t shift = g_dst.value.value() & 077;
diff --git a/debugger.cpp b/debugger.cpp
index 192df3f..65242ff 100644
--- a/debugger.cpp
+++ b/debugger.cpp
@@ -27,7 +27,7 @@ void recall_configuration(console *const c);
 #endif
 
 // returns size of instruction (in bytes)
-int disassemble(cpu *const c, console *const cnsl, const int pc, const bool instruction_only)
+int disassemble(cpu *const c, console *const cnsl, const uint16_t pc, const bool instruction_only)
 {
 	auto data      = c->disassemble(pc);
 
@@ -220,7 +220,7 @@ void debugger(console *const cnsl, bus *const b, std::atomic_uint32_t *const sto
 				continue;
 			}
 			else if (parts[0] == "disassemble" || parts[0] == "d") {
-				int pc = kv.find("pc") != kv.end() ? std::stoi(kv.find("pc")->second, nullptr, 8)  : c->getPC();
+				uint16_t pc = kv.find("pc") != kv.end() ? std::stoi(kv.find("pc")->second, nullptr, 8)  : c->getPC();
 				int n  = kv.find("n")  != kv.end() ? std::stoi(kv.find("n") ->second, nullptr, 10) : 1;
 
 				cnsl->put_string_lf(format("Disassemble %d instructions starting at %o", n, pc));
@@ -312,7 +312,7 @@ void debugger(console *const cnsl, bus *const b, std::atomic_uint32_t *const sto
 				if (parts.size() < 3)
 					cnsl->put_string_lf("parameter missing");
 				else {
-					int  addr       = std::stoi(parts[2], nullptr, 8);
+					uint16_t addr   = std::stoi(parts[2], nullptr, 8);
 					int  val        = -1;
 
 					int  n          = parts.size() == 4 ? atoi(parts[3].c_str()) : 1;
diff --git a/disk_backend_nbd.cpp b/disk_backend_nbd.cpp
index df02972..562a42a 100644
--- a/disk_backend_nbd.cpp
+++ b/disk_backend_nbd.cpp
@@ -23,7 +23,7 @@
 #define NTOHLL(x) ((1==ntohl(1)) ? (x) : (((uint64_t)ntohl((x) & 0xFFFFFFFFUL)) << 32) | ntohl((uint32_t)((x) >> 32)))
 
 
-disk_backend_nbd::disk_backend_nbd(const std::string & host, const int port) :
+disk_backend_nbd::disk_backend_nbd(const std::string & host, const unsigned port) :
 	host(host),
 	port(port)
 {
@@ -57,7 +57,7 @@ bool disk_backend_nbd::connect(const bool retry)
 		hints.ai_socktype = SOCK_STREAM;
 
 		char port_str[8] { 0 };
-		snprintf(port_str, sizeof port_str, "%d", port);
+		snprintf(port_str, sizeof port_str, "%u", port);
 
 		int rc = getaddrinfo(host.c_str(), port_str, &hints, &res);
 
diff --git a/disk_backend_nbd.h b/disk_backend_nbd.h
index 524ab27..70f65aa 100644
--- a/disk_backend_nbd.h
+++ b/disk_backend_nbd.h
@@ -11,13 +11,13 @@ class disk_backend_nbd : public disk_backend
 {
 private:
 	const std::string host;
-	const int         port {  0 };
+	const unsigned    port {  0 };
 	int               fd   { -1 };
 
 	bool connect(const bool retry);
 
 public:
-	disk_backend_nbd(const std::string & host, const int port);
+	disk_backend_nbd(const std::string & host, const unsigned port);
 	virtual ~disk_backend_nbd();
 
 	bool begin() override;
diff --git a/memory.h b/memory.h
index 9fb3b12..5942078 100644
--- a/memory.h
+++ b/memory.h
@@ -3,13 +3,14 @@
 
 #pragma once
 
+#include <assert.h>
 #include <stdint.h>
 
 class memory
 {
 private:
-	const uint32_t size;
-	uint8_t *m { nullptr };
+	const uint32_t size { 0       };
+	uint8_t       *m    { nullptr };
 
 public:
 	memory(const uint32_t size);
@@ -18,8 +19,8 @@ public:
 	void reset();
 
 	uint16_t readByte(const uint32_t a) const { return m[a]; }
-	void writeByte(const uint32_t a, const uint16_t v) { m[a] = v; }
+	void writeByte(const uint32_t a, const uint16_t v) { assert(a < size); m[a] = v; }
 
 	uint16_t readWord(const uint32_t a) const { return m[a] | (m[a + 1] << 8); }
-	void writeWord(const uint32_t a, const uint16_t v) { m[a] = v; m[a + 1] = v >> 8; }
+	void writeWord(const uint32_t a, const uint16_t v) { assert(a < size - 1); m[a] = v; m[a + 1] = v >> 8; }
 };
diff --git a/rk05.cpp b/rk05.cpp
index 3ed2745..f0d18b9 100644
--- a/rk05.cpp
+++ b/rk05.cpp
@@ -111,11 +111,11 @@ void rk05::writeWord(const uint16_t addr, uint16_t v)
 			uint8_t  surface  = (temp >> 4) & 1;
 			int      track    = (temp >> 4) & 511;
 			uint16_t cylinder = (temp >> 5) & 255;
-			uint8_t  device   = temp >> 13;
+			uint16_t device   = temp >> 13;
 
-			const int diskoff = track * 12 + sector;
+			const uint32_t diskoff = track * 12 + sector;
 
-			const int diskoffb = diskoff * 512; // RK05 is high density
+			const uint32_t diskoffb = diskoff * 512l; // RK05 is high density
 			const uint16_t memoff = registers[(RK05_BA - RK05_BASE) / 2];
 
 			registers[(RK05_CS - RK05_BASE) / 2] &= ~(1 << 13); // reset search complete
@@ -164,7 +164,7 @@ void rk05::writeWord(const uint16_t addr, uint16_t v)
 
 				uint8_t xfer_buffer[512];
 
-				int      temp_diskoffb = diskoffb;
+				uint32_t temp_diskoffb = diskoffb;
 
 				uint32_t temp = reclen;
 				uint32_t p = memoff;
@@ -224,7 +224,7 @@ void rk05::writeWord(const uint16_t addr, uint16_t v)
 
 			// bit 6, invoke interrupt when done vector address 220, see http://www.pdp-11.nl/peripherals/disk/rk05-info.html
 			if (v & 64) {
-				registers[(RK05_DS - RK05_BASE) / 2] &= ~(7 << 13);  // store id of the device that caused the interrupt
+				registers[(RK05_DS - RK05_BASE) / 2] &= ~(7l << 13);  // store id of the device that caused the interrupt
 				registers[(RK05_DS - RK05_BASE) / 2] |= device << 13;
 
 				b->getCpu()->queue_interrupt(5, 0220);
diff --git a/rl02.cpp b/rl02.cpp
index 9166411..355d3a8 100644
--- a/rl02.cpp
+++ b/rl02.cpp
@@ -124,7 +124,7 @@ void rl02::writeWord(const uint16_t addr, uint16_t v)
 
 			uint32_t memory_address = registers[(RL02_BAR - RL02_BASE) / 2];
 
-			uint32_t count          = (65536 - registers[(RL02_MPR - RL02_BASE) / 2]) * 2;
+			uint32_t count          = (65536l - registers[(RL02_MPR - RL02_BASE) / 2]) * 2;
 
 			DOLOG(debug, true, "RL02 read %d bytes (dec) from %d (dec) to %06o (oct)", count, disk_offset, memory_address);