diff --git a/include/oaknut/impl/arm64_encode_helpers.inc.hpp b/include/oaknut/impl/arm64_encode_helpers.inc.hpp
index 7bbdc8d..2675a3f 100644
--- a/include/oaknut/impl/arm64_encode_helpers.inc.hpp
+++ b/include/oaknut/impl/arm64_encode_helpers.inc.hpp
@@ -8,7 +8,7 @@ static constexpr std::uint32_t pdep(std::uint32_t val)
     std::uint32_t res = 0;
     for (std::uint32_t bb = 1; mask; bb += bb) {
         if (val & bb)
-            res |= mask & -mask;
+            res |= mask & (~mask + 1);
         mask &= mask - 1;
     }
     return res;
diff --git a/include/oaknut/impl/mnemonics_generic_v8.0.inc.hpp b/include/oaknut/impl/mnemonics_generic_v8.0.inc.hpp
index 4f5ca8f..09e8665 100644
--- a/include/oaknut/impl/mnemonics_generic_v8.0.inc.hpp
+++ b/include/oaknut/impl/mnemonics_generic_v8.0.inc.hpp
@@ -167,13 +167,13 @@ void BFI(WReg wd, WReg wn, Imm<5> lsb, Imm<5> width)
 {
     if (width.value() == 0 || width.value() > (32 - lsb.value()))
         throw OaknutException{ExceptionType::InvalidBitWidth};
-    emit<"0011001100rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(wd, wn, (-lsb.value()) & 31, width.value() - 1);
+    emit<"0011001100rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(wd, wn, (~lsb.value() + 1) & 31, width.value() - 1);
 }
 void BFI(XReg xd, XReg xn, Imm<6> lsb, Imm<6> width)
 {
     if (width.value() == 0 || width.value() > (64 - lsb.value()))
         throw OaknutException{ExceptionType::InvalidBitWidth};
-    emit<"1011001101rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(xd, xn, (-lsb.value()) & 63, width.value() - 1);
+    emit<"1011001101rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(xd, xn, (~lsb.value() + 1) & 63, width.value() - 1);
 }
 void BFM(WReg wd, WReg wn, Imm<5> immr, Imm<5> imms)
 {
@@ -1231,13 +1231,13 @@ void SBFIZ(WReg wd, WReg wn, Imm<5> lsb, Imm<5> width)
 {
     if (width.value() == 0 || width.value() > (32 - lsb.value()))
         throw OaknutException{ExceptionType::InvalidBitWidth};
-    emit<"0001001100rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(wd, wn, (-lsb.value()) & 31, width.value() - 1);
+    emit<"0001001100rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(wd, wn, (~lsb.value() + 1) & 31, width.value() - 1);
 }
 void SBFIZ(XReg xd, XReg xn, Imm<6> lsb, Imm<6> width)
 {
     if (width.value() == 0 || width.value() > (64 - lsb.value()))
         throw OaknutException{ExceptionType::InvalidBitWidth};
-    emit<"1001001101rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(xd, xn, (-lsb.value()) & 63, width.value() - 1);
+    emit<"1001001101rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(xd, xn, (~lsb.value() + 1) & 63, width.value() - 1);
 }
 void SBFM(WReg wd, WReg wn, Imm<5> immr, Imm<5> imms)
 {
@@ -1627,13 +1627,13 @@ void UBFIZ(WReg wd, WReg wn, Imm<5> lsb, Imm<5> width)
 {
     if (width.value() == 0 || width.value() > (32 - lsb.value()))
         throw OaknutException{ExceptionType::InvalidBitWidth};
-    emit<"0101001100rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(wd, wn, (-lsb.value()) & 31, width.value() - 1);
+    emit<"0101001100rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(wd, wn, (~lsb.value() + 1) & 31, width.value() - 1);
 }
 void UBFIZ(XReg xd, XReg xn, Imm<6> lsb, Imm<6> width)
 {
     if (width.value() == 0 || width.value() > (64 - lsb.value()))
         throw OaknutException{ExceptionType::InvalidBitWidth};
-    emit<"1101001101rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(xd, xn, (-lsb.value()) & 63, width.value() - 1);
+    emit<"1101001101rrrrrrssssssnnnnnddddd", "d", "n", "r", "s">(xd, xn, (~lsb.value() + 1) & 63, width.value() - 1);
 }
 void UBFM(WReg wd, WReg wn, Imm<5> immr, Imm<5> imms)
 {
diff --git a/include/oaknut/impl/mnemonics_generic_v8.2.inc.hpp b/include/oaknut/impl/mnemonics_generic_v8.2.inc.hpp
index a5bc5b8..0dffd0e 100644
--- a/include/oaknut/impl/mnemonics_generic_v8.2.inc.hpp
+++ b/include/oaknut/impl/mnemonics_generic_v8.2.inc.hpp
@@ -5,13 +5,13 @@ void BFC(WReg wd, Imm<5> lsb, Imm<5> width)
 {
     if (width.value() == 0 || width.value() > (32 - lsb.value()))
         throw OaknutException{ExceptionType::InvalidBitWidth};
-    emit<"0011001100rrrrrrssssss11111ddddd", "d", "r", "s">(wd, (-lsb.value()) & 31, width.value() - 1);
+    emit<"0011001100rrrrrrssssss11111ddddd", "d", "r", "s">(wd, (~lsb.value() + 1) & 31, width.value() - 1);
 }
 void BFC(XReg xd, Imm<6> lsb, Imm<6> width)
 {
     if (width.value() == 0 || width.value() > (64 - lsb.value()))
         throw OaknutException{ExceptionType::InvalidBitWidth};
-    emit<"1011001101rrrrrrssssss11111ddddd", "d", "r", "s">(xd, (-lsb.value()) & 63, width.value() - 1);
+    emit<"1011001101rrrrrrssssss11111ddddd", "d", "r", "s">(xd, (~lsb.value() + 1) & 63, width.value() - 1);
 }
 void ESB()
 {
diff --git a/include/oaknut/oaknut.hpp b/include/oaknut/oaknut.hpp
index a091ff5..fc0ffcc 100644
--- a/include/oaknut/oaknut.hpp
+++ b/include/oaknut/oaknut.hpp
@@ -110,8 +110,8 @@ public:
             return;
         if (MovImm16::is_valid(imm))
             return MOVZ(wd, imm);
-        if (MovImm16::is_valid(~static_cast<std::uint64_t>(imm)))
-            return MOVN(wd, ~static_cast<std::uint64_t>(imm));
+        if (MovImm16::is_valid(static_cast<std::uint32_t>(~imm)))
+            return MOVN(wd, static_cast<std::uint32_t>(~imm));
         if (detail::encode_bit_imm(imm))
             return ORR(wd, WzrReg{}, imm);