diff --git a/Research/Borland C++ decompilation.md b/Research/Borland C++ decompilation.md
index 466b4e11..c80ff860 100644
--- a/Research/Borland C++ decompilation.md	
+++ b/Research/Borland C++ decompilation.md	
@@ -118,6 +118,8 @@ inline optimally though:
 * Assignments to a pointer in `SI` – that pointer is moved to `DI`,
   [clobbering that register](#clobbering-di). Try a [class method](#C++)
   instead.
+* Nested `if` statements – inlining will always generate a useless
+  `JMP SHORT $+2` at the end of the last branch.
 
 ## Initialization
 
diff --git a/th01/hardware/input.hpp b/th01/hardware/input.hpp
index c4e7fd36..e5270368 100644
--- a/th01/hardware/input.hpp
+++ b/th01/hardware/input.hpp
@@ -3,3 +3,78 @@ extern unsigned char input_shot;
 extern bool input_ok;
 
 #define input_func_bool(var) { var = true; } else { var = false; }
+
+// REIIDEN.EXE and FUUIN.EXE
+// -------------------------
+// [input_lr] flags… hey, at least two inputs merged into a single variable.
+// It's a start.
+#define INPUT_RIGHT 0x01
+#define INPUT_LEFT 0x02
+
+extern bool input_up;
+extern bool input_down;
+extern unsigned char input_lr;
+extern bool input_strike;
+extern bool input_mem_enter;
+extern bool input_mem_leave;
+extern unsigned char paused;
+extern bool done;
+extern bool input_bomb;
+
+#define input_func_flag(var, flag) { var |= flag; } else { var &= ~flag; }
+
+#define input_onchange(prev_slot, cur_sensed, if_pressed) \
+	if(input_prev[prev_slot] != (cur_sensed)) { \
+		if(cur_sensed) if_pressed \
+	} \
+	input_prev[prev_slot] = (cur_sensed);
+
+#define input_onchange_bool(prev_slot, var, cur_sensed) \
+	input_onchange(prev_slot, cur_sensed, input_func_bool(var))
+
+#define input_onchange_flag(prev_slot, var, flag, cur_sensed) \
+	input_onchange(prev_slot, cur_sensed, input_func_flag(var, flag))
+
+#define input_onchange_2( \
+	prev_slot_1, prev_slot_2, cur_sensed_1, cur_sensed_2, if_pressed \
+) \
+	if( \
+		input_prev[prev_slot_1] != (cur_sensed_1) || \
+		input_prev[prev_slot_2] != (cur_sensed_2) \
+	) { \
+		if(cur_sensed_1 || (cur_sensed_2)) if_pressed \
+	} \
+	input_prev[prev_slot_1] = (cur_sensed_1); \
+	input_prev[prev_slot_2] = (cur_sensed_2);
+
+#define input_onchange_bool_2( \
+	prev_slot_1, prev_slot_2, var, cur_sensed_1, cur_sensed_2 \
+) \
+	input_onchange_2(prev_slot_1, prev_slot_2, \
+		cur_sensed_1, cur_sensed_2, input_func_bool(var) \
+	)
+
+#define input_onchange_flag_2( \
+	prev_slot_1, prev_slot_2, var, flag, cur_sensed_1, cur_sensed_2 \
+) \
+	input_onchange_2(prev_slot_1, prev_slot_2,  \
+		cur_sensed_1, cur_sensed_2, input_func_flag(var, flag) \
+	)
+
+#define input_pause_ok_sense(prev_slot_esc, prev_slot_ok, group0, group3) \
+	group0 = key_sense(0); \
+	group3 = key_sense(3); \
+	group0 |= key_sense(0); \
+	group3 |= key_sense(3); \
+	input_onchange(prev_slot_esc, (group0 & K0_ESC), { \
+		paused = (1 - paused); \
+	}) \
+	input_onchange(prev_slot_ok, (group3 & K3_RETURN), { \
+		if((paused == true) && (input_shot == true)) { \
+			done = true; \
+		} \
+		input_ok = true; \
+	} else { \
+		input_ok = false; \
+	});
+// -------------------------