diff --git a/.gitignore b/.gitignore
index 010439ab..fa81cd5d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -37,6 +37,8 @@
 *.o
 # In-tree binaries
 /scrypt
+/tests/check-params/check-params-normal
+/tests/check-params/check-params-reference
 /tests/libscrypt-kdf/sample-libscrypt-kdf
 /tests/valgrind/potential-memleaks
 /tests/verify-strings/test_scrypt
diff --git a/Makefile.am b/Makefile.am
index bf654d2d..f3212b4a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,5 +1,7 @@
 bin_PROGRAMS=	scrypt
 noinst_PROGRAMS=							\
+	tests/check-params/check-params-normal				\
+	tests/check-params/check-params-reference			\
 	tests/valgrind/potential-memleaks				\
 	tests/verify-strings/test_scrypt
 dist_man_MANS=$(scrypt_man_MANS)
@@ -218,6 +220,45 @@ tests_libscrypt_kdf_sample_libscrypt_kdf_CPPFLAGS=			\
 	-I$(srcdir)/libscrypt-kdf/
 tests_libscrypt_kdf_sample_libscrypt_kdf_LDADD=		libscrypt-kdf.la
 
+# Check scrypt parameter-handling (normal program, including intrinsics).
+tests_check_params_check_params_normal_SOURCES=				\
+	tests/check-params/check-params.c				\
+	$(crypto_scrypt_files)
+tests_check_params_check_params_normal_LDADD=				\
+	libcperciva_arm_sha256.la					\
+	libcperciva_cpusupport_detect.la				\
+	libcperciva_shani.la						\
+	libscrypt_sse2.la						\
+	${LDADD_POSIX}
+
+# Check scrypt parameter-handling (reference code only, no intrinsics).
+# We need a separate library for this because we need to re-compile these
+# files without -DCPUSUPPORT_CONFIG_FILE.
+noinst_LTLIBRARIES+=	libscrypt-reference.la
+libscrypt_reference_la_SOURCES=						\
+	lib/crypto/crypto_scrypt-ref.c					\
+	libcperciva/alg/sha256.c					\
+	libcperciva/alg/sha256.h					\
+	libcperciva/util/insecure_memzero.c				\
+	libcperciva/util/insecure_memzero.h				\
+	libcperciva/util/sysendian.h					\
+	libcperciva/util/warnp.c					\
+	libcperciva/util/warnp.h
+libscrypt_reference_la_CPPFLAGS=					\
+	-I$(srcdir)/lib-platform/crypto					\
+	-I$(srcdir)/lib/crypto						\
+	-I$(srcdir)/libcperciva/alg					\
+	-I$(srcdir)/libcperciva/cpusupport				\
+	-I$(srcdir)/libcperciva/util					\
+	-D_POSIX_C_SOURCE=200809L					\
+	-D_XOPEN_SOURCE=700						\
+	${CFLAGS_POSIX}
+tests_check_params_check_params_reference_SOURCES=			\
+	tests/check-params/check-params.c
+tests_check_params_check_params_reference_LDADD=			\
+	libscrypt-reference.la						\
+	${LDADD_POSIX}
+
 # crypto_aesctr_shared.c is in this list because it can't be included in the
 # _SOURCES because it should only be included as part of another translation
 # unit.
@@ -230,7 +271,6 @@ EXTRA_DIST=								\
 	STYLE								\
 	get-version.sh							\
 	lib/README							\
-	lib/crypto/crypto_scrypt-ref.c					\
 	libcperciva/POSIX/README					\
 	libcperciva/POSIX/posix-abstract-declarator.c			\
 	libcperciva/POSIX/posix-cflags.sh				\
@@ -268,6 +308,7 @@ EXTRA_DIST=								\
 	tests/07-passphrase-env.sh					\
 	tests/08-passphrase-file.sh					\
 	tests/09-explicit-params.sh					\
+	tests/10-check-params.sh					\
 	tests/shared_test_functions.sh					\
 	tests/shared_valgrind_functions.sh				\
 	tests/test_scrypt.sh						\
diff --git a/tests/10-check-params.sh b/tests/10-check-params.sh
new file mode 100644
index 00000000..b4e84f19
--- /dev/null
+++ b/tests/10-check-params.sh
@@ -0,0 +1,17 @@
+#!/bin/sh
+
+### Constants
+c_valgrind_min=1
+
+### Actual command
+scenario_cmd() {
+	# Check parameters with the normal function.
+	setup_check "check-params-normal"
+	${c_valgrind_cmd} "${bindir}/tests/check-params/check-params-normal"
+	echo $? > "${c_exitfile}"
+
+	# Check parameters with the reference function.
+	setup_check "check-params-reference"
+	${c_valgrind_cmd} "${bindir}/tests/check-params/check-params-reference"
+	echo $? > "${c_exitfile}"
+}
diff --git a/tests/check-params/check-params.c b/tests/check-params/check-params.c
new file mode 100644
index 00000000..5c6e582c
--- /dev/null
+++ b/tests/check-params/check-params.c
@@ -0,0 +1,94 @@
+#include <errno.h>
+#include <inttypes.h>
+#include <string.h>
+
+#include "warnp.h"
+
+#include "crypto_scrypt.h"
+
+/* How much data should scrypt return? */
+#define OUTPUT_BUFLEN 8
+
+static struct testcase {
+	uint64_t N;
+	uint32_t r;
+	uint32_t p;
+	int desired_errno;	/* 0 indicates no failure / errno is unset. */
+} tests[] = {
+	/* Should fail. */
+	{ 0, 0, 0, EINVAL },
+	{ 1, 1, 1, EINVAL },
+	{ 2, 0, 1, EINVAL },
+	{ 2, 1, 0, EINVAL },
+	{ 3, 1, 1, EINVAL },
+	{ 16384, 1, 2147483648, EFBIG },
+	{ 16384, 2147483648, 1, EFBIG },
+	{ 16384, 32768, 32768, EFBIG },
+	{ 16384, 65536, 65537, EFBIG },
+	{ (UINT64_C(1) << 62) + 1, 1, 1, EINVAL },
+
+	/* Should succeed. */
+	{ 2, 1, 1, 0 },
+	{ 2, 3, 1, 0 },
+	{ 2, 1, 3, 0 }
+};
+
+static int
+check_params(uint64_t N, uint32_t r, uint32_t p, int desired_errno)
+{
+	const char * passwd = "hunter2";
+	const char * salt = "DANGER -- this should be a random salt -- DANGER";
+	uint8_t output[OUTPUT_BUFLEN];
+	int rc;
+
+	/* Call crypto_scrypt. */
+	rc = crypto_scrypt((const uint8_t *)passwd, strlen(passwd),
+	    (const uint8_t *)salt, strlen(salt), N, r, p,
+	    output, OUTPUT_BUFLEN);
+
+	if (desired_errno == 0) {
+		if (rc != 0) {
+			warn0("Should have succeeded with N=%" PRIu64
+			    " r=%" PRIu32 " p=%" PRIu32, N, r, p);
+			goto err0;
+		}
+	} else {
+		if ((rc != -1) || (errno != desired_errno)) {
+			warn0("Should have errno %i with N=%" PRIu64
+			    " r=%" PRIu32 " p=%" PRIu32,
+			    desired_errno, N, r, p);
+			goto err0;
+		}
+	}
+
+	/* Success! */
+	return (0);
+
+err0:
+	/* Failure! */
+	return (-1);
+}
+
+int
+main(int argc, char * argv[])
+{
+	size_t i;
+
+	WARNP_INIT;
+
+	(void)argc; /* UNUSED */
+
+	/* Run test cases. */
+	for (i = 0; i < sizeof(tests) / sizeof(tests[0]); i++) {
+		if (check_params(tests[i].N, tests[i].r, tests[i].p,
+		    tests[i].desired_errno))
+			goto err0;
+	}
+
+	/* Success! */
+	return (0);
+
+err0:
+	/* Failure! */
+	return (1);
+}