diff --git a/sysdeps/sh/string-fzb.h b/sysdeps/sh/string-fzb.h
new file mode 100644
index 0000000000..0ad19b58c9
--- /dev/null
+++ b/sysdeps/sh/string-fzb.h
@@ -0,0 +1,54 @@
+/* Zero byte detection; boolean. SH4 version.
+ Copyright (C) 2023 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ . */
+
+#ifndef STRING_FZB_H
+#define STRING_FZB_H 1
+
+#include
+#include
+
+/* Determine if any byte within X is zero. This is a pure boolean test. */
+
+static __always_inline _Bool
+has_zero (op_t x)
+{
+ op_t zero = 0x0, ret;
+ asm volatile ("cmp/str %1,%2\n"
+ "movt %0\n"
+ : "=r" (ret)
+ : "r" (zero), "r" (x));
+ return ret;
+}
+
+/* Likewise, but for byte equality between X1 and X2. */
+
+static __always_inline _Bool
+has_eq (op_t x1, op_t x2)
+{
+ return has_zero (x1 ^ x2);
+}
+
+/* Likewise, but for zeros in X1 and equal bytes between X1 and X2. */
+
+static __always_inline _Bool
+has_zero_eq (op_t x1, op_t x2)
+{
+ return has_zero (x1) | has_eq (x1, x2);
+}
+
+#endif /* STRING_FZB_H */