diff --git a/manual.lyx b/manual.lyx
index f82ffbb7..48a7ebb9 100644
--- a/manual.lyx
+++ b/manual.lyx
@@ -2146,6 +2146,43 @@ bit.popcount(number a)
 Population count of a.
 \end_layout
 
+\begin_layout Subsubsection
+bit.clshift(number a, number b, [number amount,[number bits]])
+\end_layout
+
+\begin_layout Standard
+Does chained left shift on a, b by amount positions, assuming numbers to
+ be of specified number of bits.
+\end_layout
+
+\begin_layout Subsubsection
+bit.crshift(number a, number b, [number amount,[number bits]])
+\end_layout
+
+\begin_layout Standard
+Does chained right shift on a, b by amount positions, assuming numbers to
+ be of specified number of bits.
+\end_layout
+
+\begin_layout Subsubsection
+bit.flagdecode(number a, number bits, [string on, [string off]])
+\end_layout
+
+\begin_layout Standard
+Return string of length bits where ith character is ith character of on
+ if bit i is on, otherwise ith character of off.
+ Out of range reads give last character, or '*'/'-' if empty.
+\end_layout
+
+\begin_layout Subsubsection
+bit.rflagdecode(number a, number bits, [string on, [string off]])
+\end_layout
+
+\begin_layout Standard
+Like bit.flagdecode, but outputs the string in the opposite order (most significa
+nt bit first).
+\end_layout
+
 \begin_layout Subsection
 Table gui:
 \end_layout
diff --git a/manual.txt b/manual.txt
index 528133da..e1a53731 100644
--- a/manual.txt
+++ b/manual.txt
@@ -1059,6 +1059,31 @@ Are all set bits in b also set in a?
 
 Population count of a.
 
+8.2.15 bit.clshift(number a, number b, [number amount,[number 
+  bits]])
+
+Does chained left shift on a, b by amount positions, assuming 
+numbers to be of specified number of bits.
+
+8.2.16 bit.crshift(number a, number b, [number amount,[number 
+  bits]])
+
+Does chained right shift on a, b by amount positions, assuming 
+numbers to be of specified number of bits.
+
+8.2.17 bit.flagdecode(number a, number bits, [string on, [string 
+  off]])
+
+Return string of length bits where ith character is ith character 
+of on if bit i is on, otherwise ith character of off. Out of 
+range reads give last character, or '*'/'-' if empty.
+
+8.2.18 bit.rflagdecode(number a, number bits, [string on, [string 
+  off]])
+
+Like bit.flagdecode, but outputs the string in the opposite order 
+(most significant bit first).
+
 8.3 Table gui:
 
 Most of these functions can only be called in on_paint and 
diff --git a/src/lua/bit.cpp b/src/lua/bit.cpp
index 67951b99..e1f7e2b9 100644
--- a/src/lua/bit.cpp
+++ b/src/lua/bit.cpp
@@ -1,4 +1,5 @@
 #include "lua/internal.hpp"
+#include "library/minmax.hpp"
 
 #define BITWISE_BITS 48
 #define BITWISE_MASK ((1ULL << (BITWISE_BITS)) - 1)
@@ -165,6 +166,79 @@ namespace
 		return 1;
 	});
 
+	function_ptr_luafun lua_clshift("bit.clshift", [](lua_State* LS, const std::string& fname) -> int {
+		unsigned amount = 1;
+		unsigned bits = 48;
+		uint64_t a = get_numeric_argument<uint64_t>(LS, 1, fname.c_str());
+		uint64_t b = get_numeric_argument<uint64_t>(LS, 2, fname.c_str());
+		get_numeric_argument(LS, 3, amount, fname.c_str());
+		get_numeric_argument(LS, 4, bits, fname.c_str());
+		uint64_t mask = ((1ULL << bits) - 1);
+		a &= mask;
+		b &= mask;
+		a <<= amount;
+		a &= mask;
+		a |= (b >> (bits - amount));
+		b <<= amount;
+		b &= mask;
+		lua_pushnumber(LS, a);
+		lua_pushnumber(LS, b);
+		return 2;
+	});
+
+	function_ptr_luafun lua_crshift("bit.crshift", [](lua_State* LS, const std::string& fname) -> int {
+		unsigned amount = 1;
+		unsigned bits = 48;
+		uint64_t a = get_numeric_argument<uint64_t>(LS, 1, fname.c_str());
+		uint64_t b = get_numeric_argument<uint64_t>(LS, 2, fname.c_str());
+		get_numeric_argument(LS, 3, amount, fname.c_str());
+		get_numeric_argument(LS, 4, bits, fname.c_str());
+		uint64_t mask = ((1ULL << bits) - 1);
+		a &= mask;
+		b &= mask;
+		b >>= amount;
+		b |= (a << (bits - amount));
+		b &= mask;
+		a >>= amount;
+		lua_pushnumber(LS, a);
+		lua_pushnumber(LS, b);
+		return 2;
+	});
+
+	int flagdecode_core(lua_State* LS, const std::string& fname, bool reverse)
+	{
+		uint64_t a = get_numeric_argument<uint64_t>(LS, 1, fname.c_str());
+		uint64_t b = get_numeric_argument<uint64_t>(LS, 2, fname.c_str());
+		std::string on, off;
+		if(lua_type(LS, 3) == LUA_TSTRING)
+			on = get_string_argument(LS, 3, fname.c_str());
+		if(lua_type(LS, 4) == LUA_TSTRING)
+			off = get_string_argument(LS, 4, fname.c_str());
+		size_t onl = on.length();
+		size_t offl = off.length();
+		char onc = onl ? on[onl - 1] : '*';
+		char offc = offl ? off[offl - 1] : '-';
+		char buffer[65];
+		unsigned i;
+		size_t bias = min(b, (uint64_t)64) - 1;
+		for(i = 0; i < 64 && i < b; i++) {
+			char onc2 = (i < onl) ? on[i] : onc;
+			char offc2 = (i < offl) ? off[i] : offc;
+			buffer[reverse ? (bias - i) : i] = ((a >> i) & 1) ? onc2 : offc2;
+		}
+		buffer[i] = '\0';
+		lua_pushstring(LS, buffer);
+		return 1;
+	}
+
+	function_ptr_luafun lua_flagdecode("bit.flagdecode", [](lua_State* LS, const std::string& fname) -> int {
+		return flagdecode_core(LS, fname, false);
+	});
+
+	function_ptr_luafun lua_rflagdecode("bit.rflagdecode", [](lua_State* LS, const std::string& fname) -> int {
+		return flagdecode_core(LS, fname, true);
+	});
+
 	lua_symmetric_bitwise<combine_none, BITWISE_MASK> bit_none("bit.none");
 	lua_symmetric_bitwise<combine_none, BITWISE_MASK> bit_bnot("bit.bnot");
 	lua_symmetric_bitwise<combine_any, 0> bit_any("bit.any");