diff --git a/bus.cpp b/bus.cpp
index bed9dcb..5a15bc3 100644
--- a/bus.cpp
+++ b/bus.cpp
@@ -279,7 +279,7 @@ uint16_t bus::read(const uint16_t a, const bool word_mode, const bool use_prev,
 
 	int run_mode = (c->getPSW() >> (use_prev ? 12 : 14)) & 3;
 
-	uint32_t m_offset = calculate_physical_address(run_mode, a, !peek_only, false, peek_only);
+	uint32_t m_offset = calculate_physical_address(run_mode, a, !peek_only, false, peek_only, false);
 
 	if (word_mode)
 		temp = m -> readByte(m_offset);
@@ -291,28 +291,30 @@ uint16_t bus::read(const uint16_t a, const bool word_mode, const bool use_prev,
 	return temp;
 }
 
-uint32_t bus::calculate_physical_address(const int run_mode, const uint16_t a, const bool trap_on_failure, const bool is_write, const bool peek_only)
+uint32_t bus::calculate_physical_address(const int run_mode, const uint16_t a, const bool trap_on_failure, const bool is_write, const bool peek_only, const bool is_data)
 {
 	uint32_t m_offset = 0;
 
 	if (MMR0 & 1) {
 		const uint8_t apf = a >> 13; // active page field
 
-		// TODO: D/I
-		m_offset = pages[run_mode][0][apf].par * 64;  // memory offset  TODO: handle 16b int-s
+		constexpr uint16_t di_ena_mask[4] = { 4, 2, 0, 1 };
+		bool          d   = is_data & (!!(MMR3 & di_ena_mask[run_mode])) ? is_data : false;
 
 		uint16_t p_offset = a & 8191;  // page offset
 
+		m_offset  = pages[run_mode][d][apf].par * 64;  // memory offset  TODO: handle 16b int-s
+
 		m_offset += p_offset;
 
 		if (trap_on_failure) {
 			if (MMR0 & (1 << 9)) {
-				int access_control = pages[run_mode][0][apf].pdr & 7;
+				int access_control = pages[run_mode][d][apf].pdr & 7;
 
 				if (is_write && access_control != 6) {  // write
 					c->schedule_trap(04);  // invalid address
 
-					pages[run_mode][0][apf].pdr |= 1 << 7;  // TODO: D/I
+					pages[run_mode][d][apf].pdr |= 1 << 7;
 
 					MMR0 |= 1 << 13;  // read-only
 
@@ -327,7 +329,7 @@ uint32_t bus::calculate_physical_address(const int run_mode, const uint16_t a, c
 					if (access_control == 0 || access_control == 1 || access_control == 3 || access_control == 4 || access_control == 7) {
 						c->schedule_trap(04);  // invalid address
 
-						pages[run_mode][0][apf].pdr |= 1 << 7;  // TODO: D/I
+						pages[run_mode][d][apf].pdr |= 1 << 7;
 
 						MMR0 |= 1 << 13;  // read-only
 
@@ -341,9 +343,9 @@ uint32_t bus::calculate_physical_address(const int run_mode, const uint16_t a, c
 				}
 			}
 
-			uint16_t pdr_len = (((pages[run_mode][0][apf].pdr >> 8) & 127) + 1) * 64;  // TODO: D/I
+			uint16_t pdr_len = (((pages[run_mode][d][apf].pdr >> 8) & 127) + 1) * 64;
 
-			bool direction = pages[run_mode][0][apf].pdr & 8;  // TODO: D/I
+			bool direction = pages[run_mode][d][apf].pdr & 8;
 
 			if (m_offset >= n_pages * 8192) {
 				DOLOG(debug, !peek_only, "bus::calculate_physical_address %o >= %o", m_offset, n_pages * 8192);
@@ -351,7 +353,7 @@ uint32_t bus::calculate_physical_address(const int run_mode, const uint16_t a, c
 
 				MMR0 |= 1 << 15;  // non-resident
 
-				pages[run_mode][0][apf].pdr |= 1 << 7;  // TODO: D/I
+				pages[run_mode][d][apf].pdr |= 1 << 7;
 
 				throw 1;
 			}
@@ -362,13 +364,13 @@ uint32_t bus::calculate_physical_address(const int run_mode, const uint16_t a, c
 
 				MMR0 |= 1 << 14;  // length
 
-				pages[run_mode][0][apf].pdr |= 1 << 7;  // TODO: D/I
+				pages[run_mode][d][apf].pdr |= 1 << 7;
 
 				throw 1;
 			}
 		}
 
-		DOLOG(debug, !peek_only, "virtual address %06o maps to physical address %08o (run_mode: %d, apf: %d, par: %08o, poff)", a, m_offset, run_mode, apf, pages[run_mode][0][apf].par * 64, p_offset);  // TODO: D/I
+		DOLOG(debug, !peek_only, "virtual address %06o maps to physical address %08o (run_mode: %d, apf: %d, par: %08o, poff)", a, m_offset, run_mode, apf, pages[run_mode][d][apf].par * 64, p_offset);
 	}
 	else {
 		m_offset = a;
@@ -664,7 +666,7 @@ uint16_t bus::write(const uint16_t a, const bool word_mode, uint16_t value, cons
 
 	int run_mode = (c->getPSW() >> (use_prev ? 12 : 14)) & 3;
 
-	uint32_t m_offset = calculate_physical_address(run_mode, a, true, true, false);
+	uint32_t m_offset = calculate_physical_address(run_mode, a, true, true, false, false);
 
 	DOLOG(debug, true, "WRITE to %06o/%07o: %o", a, m_offset, value);
 
diff --git a/bus.h b/bus.h
index eb50428..8dee308 100644
--- a/bus.h
+++ b/bus.h
@@ -86,5 +86,5 @@ public:
 
 	uint16_t get_switch_register() const { return switch_register; }
 
-	uint32_t calculate_physical_address(const int run_mode, const uint16_t a, const bool trap_on_failure, const bool is_write, const bool peek_only);
+	uint32_t calculate_physical_address(const int run_mode, const uint16_t a, const bool trap_on_failure, const bool is_write, const bool peek_only, const bool is_data);
 };
diff --git a/console_ncurses.cpp b/console_ncurses.cpp
index a90b7b6..5720b85 100644
--- a/console_ncurses.cpp
+++ b/console_ncurses.cpp
@@ -139,7 +139,7 @@ void console_ncurses::panel_update_thread()
 		int      run_mode      = current_PSW >> 14;
 
 		uint16_t current_PC    = c->getPC();
-		uint32_t full_addr     = b->calculate_physical_address(run_mode, current_PC, false, false, true);
+		uint32_t full_addr     = b->calculate_physical_address(run_mode, current_PC, false, false, true, false);
 
 		uint16_t current_instr = b->readWord(current_PC);