diff --git a/tests/stxr_c.c b/tests/stxr_c.c
new file mode 100644
index 000000000..14e40c787
--- /dev/null
+++ b/tests/stxr_c.c
@@ -0,0 +1,37 @@
+#include "test.h"
+
+static uint8_t data[] = { 0x12, 0x00, 0x34 };
+
+static void
+run_test(jit_state_t *j, uint8_t *arena_base, size_t arena_size)
+{
+  jit_begin(j, arena_base, arena_size);
+
+  const jit_arg_abi_t abi[] =
+    { JIT_ARG_ABI_POINTER, JIT_ARG_ABI_INTMAX, JIT_ARG_ABI_INT8 };
+  jit_arg_t args[3];
+  const jit_anyreg_t regs[] =
+    { { .gpr=JIT_R0 }, { .gpr=JIT_R2 }, { .gpr=JIT_R1 } };
+
+  jit_receive(j, 3, abi, args);
+  jit_load_args(j, 3, abi, args, regs);
+
+  jit_stxr_c(j, JIT_R0, JIT_R2, JIT_R1);
+  jit_ret(j);
+
+  void (*f)(void*, intmax_t, int8_t) = jit_end(j, NULL);
+
+  ASSERT(data[0] == 0x12);
+  ASSERT(data[1] == 0x00);
+  ASSERT(data[2] == 0x34);
+  f(data, 1, -1);
+  ASSERT(data[0] == 0x12);
+  ASSERT(data[1] == 0xff);
+  ASSERT(data[2] == 0x34);
+}
+
+int
+main (int argc, char *argv[])
+{
+  return main_helper(argc, argv, run_test);
+}
diff --git a/tests/stxr_d.c b/tests/stxr_d.c
new file mode 100644
index 000000000..8f1d957d7
--- /dev/null
+++ b/tests/stxr_d.c
@@ -0,0 +1,37 @@
+#include "test.h"
+
+static double data[] = { -1.0, 0.0, 0.5 };
+
+static void
+run_test(jit_state_t *j, uint8_t *arena_base, size_t arena_size)
+{
+  jit_begin(j, arena_base, arena_size);
+
+  const jit_arg_abi_t abi[] =
+    { JIT_ARG_ABI_POINTER, JIT_ARG_ABI_INTMAX, JIT_ARG_ABI_DOUBLE };
+  jit_arg_t args[3];
+  const jit_anyreg_t regs[] =
+    { { .gpr=JIT_R0 }, { .gpr=JIT_R2 }, { .fpr=JIT_F0 } };
+
+  jit_receive(j, 3, abi, args);
+  jit_load_args(j, 3, abi, args, regs);
+
+  jit_stxr_d(j, JIT_R0, JIT_R2, JIT_F0);
+  jit_ret(j);
+
+  void (*f)(void*, intmax_t, double) = jit_end(j, NULL);
+
+  ASSERT(data[0] == -1.0);
+  ASSERT(data[1] == 0.0);
+  ASSERT(data[2] == 0.5);
+  f(data, 8, 42.5);
+  ASSERT(data[0] == -1.0);
+  ASSERT(data[1] == 42.5);
+  ASSERT(data[2] == 0.5);
+}
+
+int
+main (int argc, char *argv[])
+{
+  return main_helper(argc, argv, run_test);
+}
diff --git a/tests/stxr_f.c b/tests/stxr_f.c
new file mode 100644
index 000000000..7de57715c
--- /dev/null
+++ b/tests/stxr_f.c
@@ -0,0 +1,37 @@
+#include "test.h"
+
+static float data[] = { -1.0, 0.0, 0.5 };
+
+static void
+run_test(jit_state_t *j, uint8_t *arena_base, size_t arena_size)
+{
+  jit_begin(j, arena_base, arena_size);
+
+  const jit_arg_abi_t abi[] =
+    { JIT_ARG_ABI_POINTER, JIT_ARG_ABI_INTMAX, JIT_ARG_ABI_FLOAT };
+  jit_arg_t args[3];
+  const jit_anyreg_t regs[] =
+    { { .gpr=JIT_R0 }, { .gpr=JIT_R2 }, { .fpr=JIT_F0 } };
+
+  jit_receive(j, 3, abi, args);
+  jit_load_args(j, 3, abi, args, regs);
+
+  jit_stxr_f(j, JIT_R0, JIT_R2, JIT_F0);
+  jit_ret(j);
+
+  void (*f)(void*, intmax_t, float) = jit_end(j, NULL);
+
+  ASSERT(data[0] == -1.0f);
+  ASSERT(data[1] == 0.0f);
+  ASSERT(data[2] == 0.5f);
+  f(data, 4, 42.5f);
+  ASSERT(data[0] == -1.0f);
+  ASSERT(data[1] == 42.5f);
+  ASSERT(data[2] == 0.5f);
+}
+
+int
+main (int argc, char *argv[])
+{
+  return main_helper(argc, argv, run_test);
+}
diff --git a/tests/stxr_i.c b/tests/stxr_i.c
new file mode 100644
index 000000000..b613ec00a
--- /dev/null
+++ b/tests/stxr_i.c
@@ -0,0 +1,37 @@
+#include "test.h"
+
+static uint32_t data[] = { 0x12121212, 0x00000000, 0x34343434 };
+
+static void
+run_test(jit_state_t *j, uint8_t *arena_base, size_t arena_size)
+{
+  jit_begin(j, arena_base, arena_size);
+
+  const jit_arg_abi_t abi[] =
+    { JIT_ARG_ABI_POINTER, JIT_ARG_ABI_INTMAX, JIT_ARG_ABI_INT32 };
+  jit_arg_t args[3];
+  const jit_anyreg_t regs[] =
+    { { .gpr=JIT_R0 }, { .gpr=JIT_R2 }, { .gpr=JIT_R1 } };
+
+  jit_receive(j, 3, abi, args);
+  jit_load_args(j, 3, abi, args, regs);
+
+  jit_stxr_i(j, JIT_R0, JIT_R2, JIT_R1);
+  jit_ret(j);
+
+  void (*f)(void*, intmax_t, int32_t) = jit_end(j, NULL);
+
+  ASSERT(data[0] == 0x12121212);
+  ASSERT(data[1] == 0x00);
+  ASSERT(data[2] == 0x34343434);
+  f(data, 4, -1);
+  ASSERT(data[0] == 0x12121212);
+  ASSERT(data[1] == 0xffffffff);
+  ASSERT(data[2] == 0x34343434);
+}
+
+int
+main (int argc, char *argv[])
+{
+  return main_helper(argc, argv, run_test);
+}
diff --git a/tests/stxr_l.c b/tests/stxr_l.c
new file mode 100644
index 000000000..0fd239cc7
--- /dev/null
+++ b/tests/stxr_l.c
@@ -0,0 +1,39 @@
+#include "test.h"
+
+static uint64_t data[] = { 0x1212121212121212, 0, 0x3434343434343434 };
+
+static void
+run_test(jit_state_t *j, uint8_t *arena_base, size_t arena_size)
+{
+#if __WORDSIZE > 32
+  jit_begin(j, arena_base, arena_size);
+
+  const jit_arg_abi_t abi[] =
+    { JIT_ARG_ABI_POINTER, JIT_ARG_ABI_INTMAX, JIT_ARG_ABI_INT64 };
+  jit_arg_t args[3];
+  const jit_anyreg_t regs[] =
+    { { .gpr=JIT_R0 }, { .gpr=JIT_R2 }, { .gpr=JIT_R1 } };
+
+  jit_receive(j, 3, abi, args);
+  jit_load_args(j, 3, abi, args, regs);
+
+  jit_stxr_l(j, JIT_R0, JIT_R2, JIT_R1);
+  jit_ret(j);
+
+  void (*f)(void*, intmax_t, int64_t) = jit_end(j, NULL);
+
+  ASSERT(data[0] == 0x1212121212121212);
+  ASSERT(data[1] == 0x00);
+  ASSERT(data[2] == 0x3434343434343434);
+  f(data, 8, -1);
+  ASSERT(data[0] == 0x1212121212121212);
+  ASSERT(data[1] == 0xffffffffffffffff);
+  ASSERT(data[2] == 0x3434343434343434);
+#endif
+}
+
+int
+main (int argc, char *argv[])
+{
+  return main_helper(argc, argv, run_test);
+}
diff --git a/tests/stxr_s.c b/tests/stxr_s.c
new file mode 100644
index 000000000..926da5694
--- /dev/null
+++ b/tests/stxr_s.c
@@ -0,0 +1,37 @@
+#include "test.h"
+
+static uint16_t data[] = { 0x1212, 0x0000, 0x3434 };
+
+static void
+run_test(jit_state_t *j, uint8_t *arena_base, size_t arena_size)
+{
+  jit_begin(j, arena_base, arena_size);
+
+  const jit_arg_abi_t abi[] =
+    { JIT_ARG_ABI_POINTER, JIT_ARG_ABI_INTMAX, JIT_ARG_ABI_INT16 };
+  jit_arg_t args[3];
+  const jit_anyreg_t regs[] =
+    { { .gpr=JIT_R0 }, { .gpr=JIT_R2 }, { .gpr=JIT_R1 } };
+
+  jit_receive(j, 3, abi, args);
+  jit_load_args(j, 3, abi, args, regs);
+
+  jit_stxr_s(j, JIT_R0, JIT_R2, JIT_R1);
+  jit_ret(j);
+
+  void (*f)(void*, intmax_t, int16_t) = jit_end(j, NULL);
+
+  ASSERT(data[0] == 0x1212);
+  ASSERT(data[1] == 0);
+  ASSERT(data[2] == 0x3434);
+  f(data, 2, -1);
+  ASSERT(data[0] == 0x1212);
+  ASSERT(data[1] == 0xffff);
+  ASSERT(data[2] == 0x3434);
+}
+
+int
+main (int argc, char *argv[])
+{
+  return main_helper(argc, argv, run_test);
+}