diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 405ffeb..ac7b87c 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -19,6 +19,34 @@ enum reg_type {
 	REG_TYPE_BASE,
 };
 
+/**
+ * is_string_insn() - Determine if instruction is a string instruction
+ * @insn:	Instruction containing the opcode to inspect
+ *
+ * Returns:
+ *
+ * true if the instruction, determined by the opcode, is any of the
+ * string instructions as defined in the Intel Software Development manual.
+ * False otherwise.
+ */
+static bool is_string_insn(struct insn *insn)
+{
+	insn_get_opcode(insn);
+
+	/* All string instructions have a 1-byte opcode. */
+	if (insn->opcode.nbytes != 1)
+		return false;
+
+	switch (insn->opcode.bytes[0]) {
+	case 0x6c ... 0x6f:	/* INS, OUTS */
+	case 0xa4 ... 0xa7:	/* MOVS, CMPS */
+	case 0xaa ... 0xaf:	/* STOS, LODS, SCAS */
+		return true;
+	default:
+		return false;
+	}
+}
+
 static int get_reg_offset(struct insn *insn, struct pt_regs *regs,
 			  enum reg_type type)
 {