diff --git a/src/emu/cpu/i386/i386ops.h b/src/emu/cpu/i386/i386ops.h
index 00a6528cd06..60996c6cd8b 100644
--- a/src/emu/cpu/i386/i386ops.h
+++ b/src/emu/cpu/i386/i386ops.h
@@ -525,6 +525,7 @@ static const X86_OPCODE x86_opcode_table[] =
 	{ 0x7E,     OP_3BYTEF3|OP_SSE,          SSEOP(movq_r128_r128m64),       SSEOP(movq_r128_r128m64),   },
 	{ 0x7F,     OP_3BYTEF3|OP_SSE,          SSEOP(movdqu_rm128_r128),       SSEOP(movdqu_rm128_r128),   },
 	{ 0xB8,     OP_3BYTEF3|OP_PENTIUM,      PENTIUMOP(popcnt_r16_rm16),     PENTIUMOP(popcnt_r32_rm32), },
+	{ 0xBC,     OP_3BYTEF3|OP_PENTIUM,      PENTIUMOP(tzcnt_r16_rm16),      PENTIUMOP(tzcnt_r32_rm32), },
 	{ 0xC2,     OP_3BYTEF3|OP_SSE,          SSEOP(cmpss_r128_r128m32_i8),   SSEOP(cmpss_r128_r128m32_i8),},
 	{ 0xD6,     OP_3BYTEF3|OP_SSE,          SSEOP(movq2dq_r128_r64),        SSEOP(movq2dq_r128_r64),    },
 	{ 0xE6,     OP_3BYTEF3|OP_SSE,          SSEOP(cvtdq2pd_r128_r128m64),   SSEOP(cvtdq2pd_r128_r128m64)}
diff --git a/src/emu/cpu/i386/pentops.c b/src/emu/cpu/i386/pentops.c
index 5eb3d4090ae..aac1409c7dc 100644
--- a/src/emu/cpu/i386/pentops.c
+++ b/src/emu/cpu/i386/pentops.c
@@ -1159,6 +1159,20 @@ static void PENTIUMOP(popcnt_r32_rm32)(i386_state *cpustate)    // Opcode f3 0f
 	CYCLES(cpustate,1); // TODO: correct cycle count
 }
 
+static void PENTIUMOP(tzcnt_r16_rm16)(i386_state *cpustate)
+{
+	// for CPUs that don't support TZCNT, fall back to BSF
+	i386_bsf_r16_rm16(cpustate);
+	// TODO: actually implement TZCNT
+}
+
+static void PENTIUMOP(tzcnt_r32_rm32)(i386_state *cpustate)
+{
+	// for CPUs that don't support TZCNT, fall back to BSF
+	i386_bsf_r32_rm32(cpustate);
+	// TODO: actually implement TZCNT
+}
+
 INLINE INT8 SaturatedSignedWordToSignedByte(INT16 word)
 {
 	if (word > 127)