diff --git a/DevTools/UserspaceEmulator/SoftCPU.cpp b/DevTools/UserspaceEmulator/SoftCPU.cpp
index 2ddc1ccac4..02cdb3f9c7 100644
--- a/DevTools/UserspaceEmulator/SoftCPU.cpp
+++ b/DevTools/UserspaceEmulator/SoftCPU.cpp
@@ -1272,10 +1272,25 @@ void SoftCPU::NEG_RM8(const X86::Instruction& insn)
     insn.modrm().write8(*this, insn, op_sub<u8>(*this, 0, insn.modrm().read8(*this, insn)));
 }
 
-void SoftCPU::NOP(const X86::Instruction&) { TODO(); }
-void SoftCPU::NOT_RM16(const X86::Instruction&) { TODO(); }
-void SoftCPU::NOT_RM32(const X86::Instruction&) { TODO(); }
-void SoftCPU::NOT_RM8(const X86::Instruction&) { TODO(); }
+void SoftCPU::NOP(const X86::Instruction&)
+{
+}
+
+void SoftCPU::NOT_RM16(const X86::Instruction& insn)
+{
+    insn.modrm().write16(*this, insn, ~insn.modrm().read16(*this, insn));
+}
+
+void SoftCPU::NOT_RM32(const X86::Instruction& insn)
+{
+    insn.modrm().write32(*this, insn, ~insn.modrm().read32(*this, insn));
+}
+
+void SoftCPU::NOT_RM8(const X86::Instruction& insn)
+{
+    insn.modrm().write8(*this, insn, ~insn.modrm().read8(*this, insn));
+}
+
 void SoftCPU::OUTSB(const X86::Instruction&) { TODO(); }
 void SoftCPU::OUTSD(const X86::Instruction&) { TODO(); }
 void SoftCPU::OUTSW(const X86::Instruction&) { TODO(); }