diff --git a/ChangeLog b/ChangeLog
index b5a7a754b..f73029e94 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2012-12-05 Paulo Andrade <pcpa@gnu.org>
+
+	* check/ldstr.ok, check/ldstr.tst, check/ldsti.ok,
+	check/ldsti.tst, check/ldstxr.ok, check/ldstxr.tst,
+	check/ldstxi.ok, check/ldstxi.tst:
+	New test case files exercising a very large amount of
+	register combinations to verify load/store implementation.
+
+	* check/Makefile.am: Update for new test cases.
+
+	* lib/jit_x86-cpu.c: Correct wrong argument order when
+	computing REX prefix for {ld,st}r_T codes;
+
 2012-12-04 Paulo Andrade <pcpa@gnu.org>
 
 	* lib/jit_mips-fpu.c, lib/jit_mips.c: Implement missing mips
diff --git a/check/Makefile.am b/check/Makefile.am
index 450cee948..c380279be 100644
--- a/check/Makefile.am
+++ b/check/Makefile.am
@@ -32,10 +32,14 @@ EXTRA_DIST =				\
 	divi.tst	divi.ok		\
 	fib.tst		fib.ok		\
 	rpn.tst		rpn.ok		\
+	ldstr.tst	ldstr.ok	\
+	ldsti.tst	ldsti.ok	\
+	ldstxi.tst	ldstxi.ok	\
+	ldstxr.tst	ldstxr.ok	\
 	check.sh	run-test	\
 	all.tst
 
-TESTS = 3to2 add allocai bp divi fib rpn
+TESTS = 3to2 add allocai bp divi fib rpn ldstr ldsti ldstxi ldstxr
 
 CLEANFILES = $(TESTS)
 
diff --git a/check/ldsti.ok b/check/ldsti.ok
new file mode 100644
index 000000000..9766475a4
--- /dev/null
+++ b/check/ldsti.ok
@@ -0,0 +1 @@
+ok
diff --git a/check/ldsti.tst b/check/ldsti.tst
new file mode 100644
index 000000000..120e16a4a
--- /dev/null
+++ b/check/ldsti.tst
@@ -0,0 +1,241 @@
+#if __WORDSIZE == 64
+#  define L0		0x8000000000000001
+#  define LL0		L0
+#  define LC0		0xffffffffffffff81
+#  define LS0		0xffffffffffff8001
+#  define LI0		0xffffffff80000001
+#  define L1		0x8000000000000000
+#  define LL1		L1
+#  define LC1		0xffffffffffffff80
+#  define LS1		0xffffffffffff8000
+#  define LI1		0xffffffff80000000
+#  define L2		0x7fffffffffffffff
+#  define LL2		L2
+#  define LC2		0x000000000000007f
+#  define LS2		0x0000000000007fff
+#  define LI2		0x000000007fffffff
+#  define L3		0xffffffffffffffff
+#  define LL3		L3
+#  define LC3		0xffffffffffffffff
+#  define LS3		0xffffffffffffffff
+#  define LI3		0xffffffffffffffff
+#endif
+#define I0		0x80000001
+#define II0		I0
+#define IC0		0xffffff81
+#define IS0		0xffff8001
+#define I1		0x80000000
+#define II1		I1
+#define IC1		0xffffff80
+#define IS1		0xffff8000
+#define I2		0x7fffffff
+#define II2		I2
+#define IC2		0x0000007f
+#define IS2		0x00007fff
+#define I3		0xffffffff
+#define II3		I3
+#define IC3		0xffffffff
+#define IS3		0xffffffff
+#define S0		0x8001
+#define S1		0x8000
+#define S2		0x7fff
+#define S3		0xffff
+#define C0		0x81
+#define C1		0x80
+#define C2		0x7f
+#define C3		0xff
+#define F0		 0.25
+#define F1		 0.75
+#define F2		-0.25
+#define F3		-0.75
+#define D0		 0.25
+#define D1		 0.75
+#define D2		-0.25
+#define D3		-0.75
+
+.data	512
+ok:
+.c	"ok\n"
+t0:
+c0:
+.c	0
+uc0:
+.c	0
+s0:
+.s	0
+us0:
+.s	0
+.align	4
+i0:
+.i	0
+#if __WORDSIZE == 64
+ui0:
+.i	0
+.align	8
+l0:
+.l	0
+#endif
+f0:
+.f	0
+.align	8
+d0:
+.d	0
+
+#if __WORDSIZE == 64
+#  define LDSTL(N, R0)						\
+	sti_i ui0 %R0						\
+	movi %R0 L##N						\
+	sti_l l0 %R0
+
+#  define SI(C, N, x, X, R0)					\
+	ldi_##x %R0 x##0					\
+	beqi L##x##C %R0 L##X##N				\
+	calli @abort						\
+L##x##C:
+
+#  define LDRL(C, N, R0)					\
+	UI(C, N, i, I, R0)					\
+	SI(C, N, l, L, R0)
+#else
+#  define LDSTL(C, R0)
+#  define SI(C, N, x, X, R0)					\
+	ldi_##x %R0 x##0					\
+	beqi L##x##C %R0 I##X##N				\
+	calli @abort						\
+L##x##C:
+
+#  define LDRL(C, N, R0)
+
+#endif
+
+#define UI(C, N, x, X, R0)					\
+	ldi_u##x %R0 u##x##0					\
+	beqi Lu##x##C %R0 X##N					\
+	calli @abort						\
+Lu##x##C:
+
+#define FF(C, N, x, X, F0)					\
+	ldi_##x %F0 x##0					\
+	beqi_##x L##x##C %F0 X##N				\
+L##x##C:
+
+#define LDST1(X, N, R0, F0)					\
+	movi %R0 C##N						\
+	sti_c c0 %R0						\
+	sti_c uc0 %R0						\
+	movi %R0 S##N						\
+	sti_s s0 %R0						\
+	sti_s us0 %R0						\
+	movi %R0 I##N						\
+	sti_i i0 %R0						\
+	LDSTL(N, R0)						\
+	movi_f %F0 F##N						\
+	sti_f f0 %F0						\
+	movi_d %F0 D##N						\
+	sti_d d0 %F0						\
+	SI(X, N, c, C, R0)					\
+	UI(X, N, c, C, R0)					\
+	SI(X, N, s, S, R0)					\
+	UI(X, N, s, S, R0)					\
+	SI(X, N, i, I, R0)					\
+	LDRL(X, N, R0)						\
+	FF(X, N, f, F, F0)					\
+	FF(X, N, d, D, F0)
+
+#define LDST0(R0, F0)						\
+	LDST1(0_##R0##_##F0, 0, R0, F0)				\
+	LDST1(1_##R0##_##F0, 1, R0, F0)				\
+	LDST1(2_##R0##_##F0, 2, R0, F0)				\
+	LDST1(3_##R0##_##F0, 3, R0, F0)
+
+#define LDST(V0, V1, V2, R0, R1, R2, F0, F1, F2, F3, F4, F5)	\
+	LDST0(V0, F0)						\
+	LDST0(V1, F1)						\
+	LDST0(V2, F3)						\
+	LDST0(R0, F4)						\
+	LDST0(R1, F5)						\
+	LDST0(R2, F0)
+
+.code
+	jmpi main
+
+main:
+	prolog
+
+	/* Simple test to simplify validating encodings before
+	 * brute force tests */
+	movi %r1 0x81
+	sti_c c0 %r1
+	sti_c uc0 %r1
+	movi %r1 0x8001
+	sti_s s0 %r1
+	sti_s us0 %r1
+	movi %r1 0x80000001
+	sti_i i0 %r1
+#if __WORDSIZE == 64
+	sti_i ui0 %r1
+	movi %r1 0x8000000000000001
+	sti_l l0 %r1
+#endif
+	movi_f %f0 0.5
+	sti_f f0 %f0
+	movi_d %f0 0.25
+	sti_d d0 %f0
+	ldi_c %r1 c0
+#if __WORDSIZE == 32
+	beqi Lc %r1 0xffffff81
+#else
+	beqi Lc %r1 0xffffffffffffff81
+#endif
+	calli @abort
+Lc:
+	ldi_uc %r1 uc0
+	beqi Luc %r1 0x81
+	calli @abort
+Luc:
+	ldi_s %r1 s0
+#if __WORDSIZE == 32
+	beqi Ls %r1 0xffff8001
+#else
+	beqi Ls %r1 0xffffffffffff8001
+#endif
+	calli @abort
+Ls:
+	ldi_us %r1 us0
+	beqi Lus %r1 0x8001
+	calli @abort
+Lus:
+	ldi_i %r1 i0
+#if __WORDSIZE == 32
+	beqi Li %r1 0x80000001
+#else
+	beqi Li %r1 0xffffffff80000001
+#endif
+	calli @abort
+Li:
+#if __WORDSIZE == 64
+	ldi_ui %r1 ui0
+	beqi Lui %r1 0x80000001
+	calli @abort
+Lui:
+	ldi_l %r1 l0
+	beqi Ll %r1 0x8000000000000001
+	calli @abort
+Ll:
+#endif
+	ldi_f %f0 f0
+	beqi_f Lf %f0 0.5
+	calli @abort
+Lf:
+	ldi_d %f0 d0
+	beqi_d Ld %f0 0.25
+	calli @abort
+Ld:
+
+	LDST(v0, v1, v2, r0, r1, r2, f0, f1, f2, f3, f4, f5)
+	// just to know did not abort
+	prepare 1
+		pushargi ok
+	finishi @printf
+	ret
+	epilog
diff --git a/check/ldstr.ok b/check/ldstr.ok
new file mode 100644
index 000000000..9766475a4
--- /dev/null
+++ b/check/ldstr.ok
@@ -0,0 +1 @@
+ok
diff --git a/check/ldstr.tst b/check/ldstr.tst
new file mode 100644
index 000000000..5ab255d2f
--- /dev/null
+++ b/check/ldstr.tst
@@ -0,0 +1,290 @@
+#if __WORDSIZE == 64
+#  define L0		0x8000000000000001
+#  define LL0		L0
+#  define LC0		0xffffffffffffff81
+#  define LS0		0xffffffffffff8001
+#  define LI0		0xffffffff80000001
+#  define L1		0x8000000000000000
+#  define LL1		L1
+#  define LC1		0xffffffffffffff80
+#  define LS1		0xffffffffffff8000
+#  define LI1		0xffffffff80000000
+#  define L2		0x7fffffffffffffff
+#  define LL2		L2
+#  define LC2		0x000000000000007f
+#  define LS2		0x0000000000007fff
+#  define LI2		0x000000007fffffff
+#  define L3		0xffffffffffffffff
+#  define LL3		L3
+#  define LC3		0xffffffffffffffff
+#  define LS3		0xffffffffffffffff
+#  define LI3		0xffffffffffffffff
+#endif
+#define I0		0x80000001
+#define II0		I0
+#define IC0		0xffffff81
+#define IS0		0xffff8001
+#define I1		0x80000000
+#define II1		I1
+#define IC1		0xffffff80
+#define IS1		0xffff8000
+#define I2		0x7fffffff
+#define II2		I2
+#define IC2		0x0000007f
+#define IS2		0x00007fff
+#define I3		0xffffffff
+#define II3		I3
+#define IC3		0xffffffff
+#define IS3		0xffffffff
+#define S0		0x8001
+#define S1		0x8000
+#define S2		0x7fff
+#define S3		0xffff
+#define C0		0x81
+#define C1		0x80
+#define C2		0x7f
+#define C3		0xff
+#define F0		 0.25
+#define F1		 0.75
+#define F2		-0.25
+#define F3		-0.75
+#define D0		 0.25
+#define D1		 0.75
+#define D2		-0.25
+#define D3		-0.75
+
+.data	512
+ok:
+.c	"ok\n"
+t0:
+c0:
+.c	0
+uc0:
+.c	0
+s0:
+.s	0
+us0:
+.s	0
+.align	4
+i0:
+.i	0
+#if __WORDSIZE == 64
+ui0:
+.i	0
+.align	8
+l0:
+.l	0
+#endif
+f0:
+.f	0
+.align	8
+d0:
+.d	0
+
+.	$($offc  = c0  - t0)
+.	$($offuc = uc0 - t0)
+.	$($offs  = s0  - t0)
+.	$($offus = us0 - t0)
+.	$($offi  = i0  - t0)
+#if __WORDSIZE == 64
+.	$($offui = ui0 - t0)
+.	$($offl  = l0  - t0)
+#endif
+.	$($offf  = f0  - t0)
+.	$($offd  = d0  - t0)
+
+#if __WORDSIZE == 64
+#  define LDSTL(N, R0, R1)					\
+	movi %R0 $(t0 + $offui)					\
+	str_i %R0 %R1						\
+	movi %R0 $(t0 + $offl)					\
+	movi %R1 L##N						\
+	str_l %R0 %R1
+
+#  define SI(C, N, x, X, R0, R1)				\
+	movi %R0 $(t0 + $off##x)				\
+	ldr_##x %R1 %R0						\
+	beqi L##x##C %R1 L##X##N				\
+	calli @abort						\
+L##x##C:
+
+#  define LDRL(C, N, R0, R1)					\
+	UI(C, N, i, I, R0, R1)					\
+	SI(C, N, l, L, R0, R1)
+#else
+#  define LDSTL(C, R0, R1)
+#  define SI(C, N, x, X, R0, R1)				\
+	movi %R0 $(t0 + $off##x)				\
+	ldr_##x %R1 %R0						\
+	beqi L##x##C %R1 I##X##N				\
+	calli @abort						\
+L##x##C:
+
+#  define LDRL(C, N, R0, R1)
+
+#endif
+
+#define UI(C, N, x, X, R0, R1)					\
+	movi %R0 $(t0 + $offu##x)				\
+	ldr_u##x %R1 %R0					\
+	beqi Lu##x##C %R1 X##N					\
+	calli @abort						\
+Lu##x##C:
+
+#define FF(C, N, x, X, R0, F0)					\
+	movi %R0 $(t0 + $off##x)				\
+	ldr_##x %F0 %R0						\
+	beqi_##x L##x##C %F0 X##N				\
+L##x##C:
+
+#define LDST1(X, N, R0, R1, F0)					\
+	movi %R0 $(t0 + $offc)					\
+	movi %R1 C##N						\
+	str_c %R0 %R1						\
+	movi %R0 $(t0 + $offuc)					\
+	str_c %R0 %R1						\
+	movi %R0 $(t0 + $offs)					\
+	movi %R1 S##N						\
+	str_s %R0 %R1						\
+	movi %R0 $(t0 + $offus)					\
+	str_s %R0 %R1						\
+	movi %R0 $(t0 + $offi)					\
+	movi %R1 I##N						\
+	str_i %R0 %R1						\
+	LDSTL(N, R0, R1)					\
+	movi %R0 $(t0 + $offf)					\
+	movi_f %F0 F##N						\
+	str_f %R0 %F0						\
+	movi %R0 $(t0 + $offd)					\
+	movi_d %F0 D##N						\
+	str_d %R0 %F0						\
+	SI(X, N, c, C, R0, R1)					\
+	UI(X, N, c, C, R0, R1)					\
+	SI(X, N, s, S, R0, R1)					\
+	UI(X, N, s, S, R0, R1)					\
+	SI(X, N, i, I, R0, R1)					\
+	LDRL(X, N, R0, R1)					\
+	FF(X, N, f, F, R0, F0)					\
+	FF(X, N, d, D, R0, F0)
+
+#define LDST0(R0, R1, F0)					\
+	LDST1(0_##R0##_##R1##_##F0, 0, R0, R1, F0)		\
+	LDST1(1_##R0##_##R1##_##F0, 1, R0, R1, F0)		\
+	LDST1(2_##R0##_##R1##_##F0, 2, R0, R1, F0)		\
+	LDST1(3_##R0##_##R1##_##F0, 3, R0, R1, F0)
+
+#define LDST(V0, V1, V2, R0, R1, R2, F0, F1, F2, F3, F4, F5)	\
+	LDST0(V0, V1, F0)					\
+	LDST0(V0, V2, F1)					\
+	LDST0(V0, R0, F3)					\
+	LDST0(V0, R1, F4)					\
+	LDST0(V0, R2, F5)					\
+	LDST0(V1, V2, F0)					\
+	LDST0(V1, R0, F1)					\
+	LDST0(V1, R1, F2)					\
+	LDST0(V1, R2, F3)					\
+	LDST0(V2, R0, F4)					\
+	LDST0(V2, R1, F5)					\
+	LDST0(V2, R2, F0)
+
+.code
+	jmpi main
+
+main:
+	prolog
+
+	/* Simple test to simplify validating encodings before
+	 * brute force tests */
+	movi %r0 $(t0 + $offc)
+	movi %r1 0x81
+	str_c %r0 %r1
+	movi %r0 $(t0 + $offuc)
+	str_c %r0 %r1
+	movi %r0 $(t0 + $offs)
+	movi %r1 0x8001
+	str_s %r0 %r1
+	movi %r0 $(t0 + $offus)
+	str_s %r0 %r1
+	movi %r0 $(t0 + $offi)
+	movi %r1 0x80000001
+	str_i %r0 %r1
+#if __WORDSIZE == 64
+	movi %r0 $(t0 + $offui)
+	str_i %r0 %r1
+	movi %r0 $(t0 + $offl)
+	movi %r1 0x8000000000000001
+	str_l %r0 %r1
+#endif
+	movi %r0 $(t0 + $offf)
+	movi_f %f0 0.5
+	str_f %r0 %f0
+	movi %r0 $(t0 + $offd)
+	movi_d %f0 0.25
+	str_d %r0 %f0
+	movi %r0 $(t0 + $offc)
+	ldr_c %r1 %r0
+#if __WORDSIZE == 32
+	beqi Lc %r1 0xffffff81
+#else
+	beqi Lc %r1 0xffffffffffffff81
+#endif
+	calli @abort
+Lc:
+	movi %r0 $(t0 + $offuc)
+	ldr_uc %r1 %r0
+	beqi Luc %r1 0x81
+	calli @abort
+Luc:
+	movi %r0 $(t0 + $offs)
+	ldr_s %r1 %r0
+#if __WORDSIZE == 32
+	beqi Ls %r1 0xffff8001
+#else
+	beqi Ls %r1 0xffffffffffff8001
+#endif
+	calli @abort
+Ls:
+	movi %r0 $(t0 + $offus)
+	ldr_us %r1 %r0
+	beqi Lus %r1 0x8001
+	calli @abort
+Lus:
+	movi %r0 $(t0 + $offi)
+	ldr_i %r1 %r0
+#if __WORDSIZE == 32
+	beqi Li %r1 0x80000001
+#else
+	beqi Li %r1 0xffffffff80000001
+#endif
+	calli @abort
+Li:
+#if __WORDSIZE == 64
+	movi %r0 $(t0 + $offui)
+	ldr_ui %r1 %r0
+	beqi Lui %r1 0x80000001
+	calli @abort
+Lui:
+	movi %r0 $(t0 + $offl)
+	ldr_l %r1 %r0
+	beqi Ll %r1 0x8000000000000001
+	calli @abort
+Ll:
+#endif
+	movi %r0 $(t0 + $offf)
+	ldr_f %f0 %r0
+	beqi_f Lf %f0 0.5
+	calli @abort
+Lf:
+	movi %r0 $(t0 + $offd)
+	ldr_d %f0 %r0
+	beqi_d Ld %f0 0.25
+	calli @abort
+Ld:
+
+	LDST(v0, v1, v2, r0, r1, r2, f0, f1, f2, f3, f4, f5)
+	// just to know did not abort
+	prepare 1
+		pushargi ok
+	finishi @printf
+	ret
+	epilog
diff --git a/check/ldstxi.ok b/check/ldstxi.ok
new file mode 100644
index 000000000..9766475a4
--- /dev/null
+++ b/check/ldstxi.ok
@@ -0,0 +1 @@
+ok
diff --git a/check/ldstxi.tst b/check/ldstxi.tst
new file mode 100644
index 000000000..e981b7ff4
--- /dev/null
+++ b/check/ldstxi.tst
@@ -0,0 +1,261 @@
+#if __WORDSIZE == 64
+#  define L0		0x8000000000000001
+#  define LL0		L0
+#  define LC0		0xffffffffffffff81
+#  define LS0		0xffffffffffff8001
+#  define LI0		0xffffffff80000001
+#  define L1		0x8000000000000000
+#  define LL1		L1
+#  define LC1		0xffffffffffffff80
+#  define LS1		0xffffffffffff8000
+#  define LI1		0xffffffff80000000
+#  define L2		0x7fffffffffffffff
+#  define LL2		L2
+#  define LC2		0x000000000000007f
+#  define LS2		0x0000000000007fff
+#  define LI2		0x000000007fffffff
+#  define L3		0xffffffffffffffff
+#  define LL3		L3
+#  define LC3		0xffffffffffffffff
+#  define LS3		0xffffffffffffffff
+#  define LI3		0xffffffffffffffff
+#endif
+#define I0		0x80000001
+#define II0		I0
+#define IC0		0xffffff81
+#define IS0		0xffff8001
+#define I1		0x80000000
+#define II1		I1
+#define IC1		0xffffff80
+#define IS1		0xffff8000
+#define I2		0x7fffffff
+#define II2		I2
+#define IC2		0x0000007f
+#define IS2		0x00007fff
+#define I3		0xffffffff
+#define II3		I3
+#define IC3		0xffffffff
+#define IS3		0xffffffff
+#define S0		0x8001
+#define S1		0x8000
+#define S2		0x7fff
+#define S3		0xffff
+#define C0		0x81
+#define C1		0x80
+#define C2		0x7f
+#define C3		0xff
+#define F0		 0.25
+#define F1		 0.75
+#define F2		-0.25
+#define F3		-0.75
+#define D0		 0.25
+#define D1		 0.75
+#define D2		-0.25
+#define D3		-0.75
+
+.data	512
+ok:
+.c	"ok\n"
+t0:
+c0:
+.c	0
+uc0:
+.c	0
+s0:
+.s	0
+us0:
+.s	0
+.align	4
+i0:
+.i	0
+#if __WORDSIZE == 64
+ui0:
+.i	0
+.align	8
+l0:
+.l	0
+#endif
+f0:
+.f	0
+.align	8
+d0:
+.d	0
+
+.	$($offc  = c0  - t0)
+.	$($offuc = uc0 - t0)
+.	$($offs  = s0  - t0)
+.	$($offus = us0 - t0)
+.	$($offi  = i0  - t0)
+#if __WORDSIZE == 64
+.	$($offui = ui0 - t0)
+.	$($offl  = l0  - t0)
+#endif
+.	$($offf  = f0  - t0)
+.	$($offd  = d0  - t0)
+
+#if __WORDSIZE == 64
+#  define LDSTL(N, R0, R1)					\
+	stxi_i $offui %R0 %R1					\
+	movi %R1 L##N						\
+	stxi_l $offl %R0 %R1
+
+#  define SI(C, N, x, X, R0, R1)				\
+	ldxi_##x %R1 %R0 $off##x				\
+	beqi L##x##C %R1 L##X##N				\
+	calli @abort						\
+L##x##C:
+
+#  define LDRL(C, N, R0, R1)					\
+	UI(C, N, i, I, R0, R1)					\
+	SI(C, N, l, L, R0, R1)
+#else
+#  define LDSTL(C, R0, R1)
+#  define SI(C, N, x, X, R0, R1)				\
+	ldxi_##x $off##x %R1 %R0				\
+	beqi L##x##C %R1 I##X##N				\
+	calli @abort						\
+L##x##C:
+
+#  define LDRL(C, N, R0, R1)
+
+#endif
+
+#define UI(C, N, x, X, R0, R1)					\
+	ldxi_u##x %R1 %R0 $offu##x				\
+	beqi Lu##x##C %R1 X##N					\
+	calli @abort						\
+Lu##x##C:
+
+#define FF(C, N, x, X, R0, F0)					\
+	ldxi_##x %F0 %R0 $off##x				\
+	beqi_##x L##x##C %F0 X##N				\
+L##x##C:
+
+#define LDST1(X, N, R0, R1, F0)					\
+	movi %R0 t0						\
+	movi %R1 C##N						\
+	stxi_c $offc %R0 %R1					\
+	stxi_c $offuc %R0 %R1					\
+	movi %R1 S##N						\
+	stxi_s $offs %R0 %R1					\
+	stxi_s $offus %R0 %R1					\
+	movi %R1 I##N						\
+	stxi_i $offi %R0 %R1					\
+	LDSTL(N, R0, R1)					\
+	movi_f %F0 F##N						\
+	stxi_f $offf %R0 %F0					\
+	movi_d %F0 D##N						\
+	stxi_d $offd %R0 %F0					\
+	SI(X, N, c, C, R0, R1)					\
+	UI(X, N, c, C, R0, R1)					\
+	SI(X, N, s, S, R0, R1)					\
+	UI(X, N, s, S, R0, R1)					\
+	SI(X, N, i, I, R0, R1)					\
+	LDRL(X, N, R0, R1)					\
+	FF(X, N, f, F, R0, F0)					\
+	FF(X, N, d, D, R0, F0)
+
+#define LDST0(R0, R1, F0)					\
+	LDST1(0_##R0##_##R1##_##F0, 0, R0, R1, F0)		\
+	LDST1(1_##R0##_##R1##_##F0, 1, R0, R1, F0)		\
+	LDST1(2_##R0##_##R1##_##F0, 2, R0, R1, F0)		\
+	LDST1(3_##R0##_##R1##_##F0, 3, R0, R1, F0)
+
+#define LDST(V0, V1, V2, R0, R1, R2, F0, F1, F2, F3, F4, F5)	\
+	LDST0(V0, V1, F0)					\
+	LDST0(V0, V2, F1)					\
+	LDST0(V0, R0, F3)					\
+	LDST0(V0, R1, F4)					\
+	LDST0(V0, R2, F5)					\
+	LDST0(V1, V2, F0)					\
+	LDST0(V1, R0, F1)					\
+	LDST0(V1, R1, F2)					\
+	LDST0(V1, R2, F3)					\
+	LDST0(V2, R0, F4)					\
+	LDST0(V2, R1, F5)					\
+	LDST0(V2, R2, F0)
+
+.code
+	jmpi main
+
+main:
+	prolog
+
+	/* Simple test to simplify validating encodings before
+	 * brute force tests */
+	movi %r0 t0
+	movi %r1 0x81
+	stxi_c $offc %r0 %r1
+	stxi_c $offuc %r0 %r1
+	movi %r1 0x8001
+	stxi_s $offs %r0 %r1
+	stxi_s $offus %r0 %r1
+	movi %r1 0x80000001
+	stxi_i $offi %r0 %r1
+#if __WORDSIZE == 64
+	stxi_i $offui %r0 %r1
+	movi %r1 0x8000000000000001
+	stxi_l $offl %r0 %r1
+#endif
+	movi_f %f0 0.5
+	stxi_f $offf %r0 %f0
+	movi_d %f0 0.25
+	stxi_d $offd %r0 %f0
+	ldxi_c %r1 %r0 $offc
+#if __WORDSIZE == 32
+	beqi Lc %r1 0xffffff81
+#else
+	beqi Lc %r1 0xffffffffffffff81
+#endif
+	calli @abort
+Lc:
+	ldxi_uc %r1 %r0 $offuc
+	beqi Luc %r1 0x81
+	calli @abort
+Luc:
+	ldxi_s %r1 %r0 $offs
+#if __WORDSIZE == 32
+	beqi Ls %r1 0xffff8001
+#else
+	beqi Ls %r1 0xffffffffffff8001
+#endif
+	calli @abort
+Ls:
+	ldxi_us %r1 %r0 $offus
+	beqi Lus %r1 0x8001
+	calli @abort
+Lus:
+	ldxi_i %r1 %r0 $offi
+#if __WORDSIZE == 32
+	beqi Li %r1 0x80000001
+#else
+	beqi Li %r1 0xffffffff80000001
+#endif
+	calli @abort
+Li:
+#if __WORDSIZE == 64
+	ldxi_ui %r1 %r0 $offui
+	beqi Lui %r1 0x80000001
+	calli @abort
+Lui:
+	ldxi_l %r1 %r0 $offl
+	beqi Ll %r1 0x8000000000000001
+	calli @abort
+Ll:
+#endif
+	ldxi_f %f0 %r0 $offf
+	beqi_f Lf %f0 0.5
+	calli @abort
+Lf:
+	ldxi_d %f0 %r0 $offd
+	beqi_d Ld %f0 0.25
+	calli @abort
+Ld:
+
+	LDST(v0, v1, v2, r0, r1, r2, f0, f1, f2, f3, f4, f5)
+	// just to know did not abort
+	prepare 1
+		pushargi ok
+	finishi @printf
+	ret
+	epilog
diff --git a/check/ldstxr.ok b/check/ldstxr.ok
new file mode 100644
index 000000000..9766475a4
--- /dev/null
+++ b/check/ldstxr.ok
@@ -0,0 +1 @@
+ok
diff --git a/check/ldstxr.tst b/check/ldstxr.tst
new file mode 100644
index 000000000..c989cb686
--- /dev/null
+++ b/check/ldstxr.tst
@@ -0,0 +1,318 @@
+#if __WORDSIZE == 64
+#  define L0		0x8000000000000001
+#  define LL0		L0
+#  define LC0		0xffffffffffffff81
+#  define LS0		0xffffffffffff8001
+#  define LI0		0xffffffff80000001
+#  define L1		0x8000000000000000
+#  define LL1		L1
+#  define LC1		0xffffffffffffff80
+#  define LS1		0xffffffffffff8000
+#  define LI1		0xffffffff80000000
+#  define L2		0x7fffffffffffffff
+#  define LL2		L2
+#  define LC2		0x000000000000007f
+#  define LS2		0x0000000000007fff
+#  define LI2		0x000000007fffffff
+#  define L3		0xffffffffffffffff
+#  define LL3		L3
+#  define LC3		0xffffffffffffffff
+#  define LS3		0xffffffffffffffff
+#  define LI3		0xffffffffffffffff
+#endif
+#define I0		0x80000001
+#define II0		I0
+#define IC0		0xffffff81
+#define IS0		0xffff8001
+#define I1		0x80000000
+#define II1		I1
+#define IC1		0xffffff80
+#define IS1		0xffff8000
+#define I2		0x7fffffff
+#define II2		I2
+#define IC2		0x0000007f
+#define IS2		0x00007fff
+#define I3		0xffffffff
+#define II3		I3
+#define IC3		0xffffffff
+#define IS3		0xffffffff
+#define S0		0x8001
+#define S1		0x8000
+#define S2		0x7fff
+#define S3		0xffff
+#define C0		0x81
+#define C1		0x80
+#define C2		0x7f
+#define C3		0xff
+#define F0		 0.25
+#define F1		 0.75
+#define F2		-0.25
+#define F3		-0.75
+#define D0		 0.25
+#define D1		 0.75
+#define D2		-0.25
+#define D3		-0.75
+
+.data	512
+ok:
+.c	"ok\n"
+t0:
+c0:
+.c	0
+uc0:
+.c	0
+s0:
+.s	0
+us0:
+.s	0
+.align	4
+i0:
+.i	0
+#if __WORDSIZE == 64
+ui0:
+.i	0
+.align	8
+l0:
+.l	0
+#endif
+f0:
+.f	0
+.align	8
+d0:
+.d	0
+
+.	$($offc  = c0  - t0)
+.	$($offuc = uc0 - t0)
+.	$($offs  = s0  - t0)
+.	$($offus = us0 - t0)
+.	$($offi  = i0  - t0)
+#if __WORDSIZE == 64
+.	$($offui = ui0 - t0)
+.	$($offl  = l0  - t0)
+#endif
+.	$($offf  = f0  - t0)
+.	$($offd  = d0  - t0)
+
+#if __WORDSIZE == 64
+#  define LDSTL(N, R0, R1, R2)					\
+	movi %R2 $offui						\
+	stxr_i %R2 %R0 %R1					\
+	movi %R1 L##N						\
+	movi %R2 $offl						\
+	stxr_l %R2 %R0 %R1
+
+#  define SI(C, N, x, X, R0, R1, R2)				\
+	movi %R2 $off##x					\
+	ldxr_##x %R1 %R0 %R2					\
+	beqi L##x##C %R1 L##X##N				\
+	calli @abort						\
+L##x##C:
+
+#  define LDRL(C, N, R0, R1, R2)				\
+	UI(C, N, i, I, R0, R1, R2)				\
+	SI(C, N, l, L, R0, R1, R2)
+#else
+#  define LDSTL(C, R0, R1, R2)
+#  define SI(C, N, x, X, R0, R1, R2)				\
+	movi %R2 $off##x					\
+	ldxr_##x %R2 %R1 %R0					\
+	beqi L##x##C %R1 I##X##N				\
+	calli @abort						\
+L##x##C:
+
+#  define LDRL(C, N, R0, R1, R2)
+
+#endif
+
+#define UI(C, N, x, X, R0, R1, R2)				\
+	movi %R2 $offu##x					\
+	ldxr_u##x %R1 %R0 %R2					\
+	beqi Lu##x##C %R1 X##N					\
+	calli @abort						\
+Lu##x##C:
+
+#define FF(C, N, x, X, R0, R1, F0)				\
+	movi %R1 $off##x					\
+	ldxr_##x %F0 %R0 %R1					\
+	beqi_##x L##x##C %F0 X##N				\
+L##x##C:
+
+#define LDST1(X, N, R0, R1, R2, F0)				\
+	movi %R0 t0						\
+	movi %R1 C##N						\
+	movi %R2 $offc						\
+	stxr_c %R2 %R0 %R1					\
+	movi %R2 $offuc						\
+	stxr_c %R2 %R0 %R1					\
+	movi %R1 S##N						\
+	movi %R2 $offs						\
+	stxr_s %R2 %R0 %R1					\
+	movi %R2 $offus						\
+	stxr_s %R2 %R0 %R1					\
+	movi %R1 I##N						\
+	movi %R2 $offi						\
+	stxr_i %R2 %R0 %R1					\
+	LDSTL(N, R0, R1, R2)					\
+	movi_f %F0 F##N						\
+	movi %R2 $offf						\
+	stxr_f %R2 %R0 %F0					\
+	movi_d %F0 D##N						\
+	movi %R2 $offd						\
+	stxr_d %R2 %R0 %F0					\
+	SI(X, N, c, C, R0, R1, R2)				\
+	UI(X, N, c, C, R0, R1, R2)				\
+	SI(X, N, s, S, R0, R1, R2)				\
+	UI(X, N, s, S, R0, R1, R2)				\
+	SI(X, N, i, I, R0, R1, R2)				\
+	LDRL(X, N, R0, R1, R2)					\
+	FF(X, N, f, F, R0, R1, F0)				\
+	FF(X, N, d, D, R0, R1, F0)
+
+#define LDST0(R0, R1, R2, F0)					\
+	LDST1(0_##R0##_##R1##_##R2##_##F0, 0, R0, R1, R2, F0)	\
+	LDST1(1_##R0##_##R1##_##R2##_##F0, 1, R0, R1, R2, F0)	\
+	LDST1(2_##R0##_##R1##_##R2##_##F0, 2, R0, R1, R2, F0)	\
+	LDST1(3_##R0##_##R1##_##R2##_##F0, 3, R0, R1, R2, F0)
+
+#define LDST(V0, V1, V2, R0, R1, R2, F0, F1, F2, F3, F4, F5)	\
+	LDST0(V0, V1, R0, F0)					\
+	LDST0(V0, V1, R1, F1)					\
+	LDST0(V0, V1, R2, F2)					\
+	LDST0(V0, V2, R0, F3)					\
+	LDST0(V0, V2, R1, F4)					\
+	LDST0(V0, V2, R2, F5)					\
+	LDST0(V0, R0, V1, F0)					\
+	LDST0(V0, R0, V2, F1)					\
+	LDST0(V0, R0, R1, F2)					\
+	LDST0(V0, R0, R2, F3)					\
+	LDST0(V0, R0, V1, F4)					\
+	LDST0(V0, R1, V1, F5)					\
+	LDST0(V0, R1, V2, F0)					\
+	LDST0(V0, R1, R0, F1)					\
+	LDST0(V0, R1, R2, F2)					\
+	LDST0(V0, V1, V2, F3)					\
+	LDST0(V0, R1, R0, F4)					\
+	LDST0(V0, R1, R2, F5)					\
+	LDST0(R0, V1, V0, F0)					\
+	LDST0(R0, V1, R1, F1)					\
+	LDST0(R0, V1, R2, F2)					\
+	LDST0(R0, V2, V0, F3)					\
+	LDST0(R0, V2, R1, F4)					\
+	LDST0(R0, V2, R2, F5)					\
+	LDST0(R0, V0, V1, F0)					\
+	LDST0(R0, V0, V2, F1)					\
+	LDST0(R0, V0, R1, F2)					\
+	LDST0(R0, V0, R2, F3)					\
+	LDST0(R0, V0, V1, F4)					\
+	LDST0(R0, R1, V1, F5)					\
+	LDST0(R0, R1, V2, F0)					\
+	LDST0(R0, R1, V0, F1)					\
+	LDST0(R0, R1, R2, F2)					\
+	LDST0(R0, V1, V2, F3)					\
+	LDST0(R0, R1, V0, F4)					\
+	LDST0(R0, R1, R2, F5)
+
+.code
+	jmpi main
+
+main:
+	prolog
+
+#if 0
+	/* Simple test to simplify validating encodings before
+	 * brute force tests */
+	movi %r0 t0
+	movi %r1 0x81
+	movi %r2 $offc
+	stxr_c %r2 %r0 %r1
+	movi %r2 $offuc
+	stxr_c %r2 %r0 %r1
+	movi %r1 0x8001
+	movi %r2 $offs
+	stxr_s %r2 %r0 %r1
+	movi %r2 $offus
+	stxr_s %r2 %r0 %r1
+	movi %r1 0x80000001
+	movi %r2 $offi
+	stxr_i %r2 %r0 %r1
+#if __WORDSIZE == 64
+	movi %r2 $offui
+	stxr_i %r2 %r0 %r1
+	movi %r1 0x8000000000000001
+	movi %r2 $offl
+	stxr_l %r2 %r0 %r1
+#endif
+	movi_f %f0 0.5
+	movi %r2 $offf
+	stxr_f %r2 %r0 %f0
+	movi_d %f0 0.25
+	movi %r2 $offd
+	stxr_d %r2 %r0 %f0
+	movi %r2 $offc
+	ldxr_c %r1 %r0 %r2
+#if __WORDSIZE == 32
+	beqi Lc %r1 0xffffff81
+#else
+	beqi Lc %r1 0xffffffffffffff81
+#endif
+	calli @abort
+Lc:
+	movi %r2 $offuc
+	ldxr_uc %r1 %r0 %r2
+	beqi Luc %r1 0x81
+	calli @abort
+Luc:
+	movi %r2 $offs
+	ldxr_s %r1 %r0 %r2
+#if __WORDSIZE == 32
+	beqi Ls %r1 0xffff8001
+#else
+	beqi Ls %r1 0xffffffffffff8001
+#endif
+	calli @abort
+Ls:
+	movi %r2 $offus
+	ldxr_us %r1 %r0 %r2
+	beqi Lus %r1 0x8001
+	calli @abort
+Lus:
+	movi %r2 $offi
+	ldxr_i %r1 %r0 %r2
+#if __WORDSIZE == 32
+	beqi Li %r1 0x80000001
+#else
+	beqi Li %r1 0xffffffff80000001
+#endif
+	calli @abort
+Li:
+#if __WORDSIZE == 64
+	movi %r2 $offui
+	ldxr_ui %r1 %r0 %r2
+	beqi Lui %r1 0x80000001
+	calli @abort
+Lui:
+	movi %r2 $offl
+	ldxr_l %r1 %r0 %r2
+	beqi Ll %r1 0x8000000000000001
+	calli @abort
+Ll:
+#endif
+	movi %r2 $offf
+	ldxr_f %f0 %r0 %r2
+	beqi_f Lf %f0 0.5
+	calli @abort
+Lf:
+	movi %r2 $offd
+	ldxr_d %f0 %r0 %r2
+	beqi_d Ld %f0 0.25
+	calli @abort
+Ld:
+#endif
+
+	LDST(v0, v1, v2, r0, r1, r2, f0, f1, f2, f3, f4, f5)
+	// just to know did not abort
+	prepare 1
+		pushargi ok
+	finishi @printf
+	ret
+	epilog
diff --git a/lib/jit_x86-cpu.c b/lib/jit_x86-cpu.c
index 44e1706cd..60b57df74 100644
--- a/lib/jit_x86-cpu.c
+++ b/lib/jit_x86-cpu.c
@@ -1965,7 +1965,7 @@ _ldr_uc(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1)
 {
     rex(0, 1, r0, _NOREG, r1);
     ic(0x0f);
-    ic(0xbe);
+    ic(0xb6);
     rx(r0, 0, r1, _NOREG, _SCL1);
 }
 
@@ -2324,7 +2324,7 @@ _str_c(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1)
 {
     jit_int32_t		reg;
     if (reg8_p(r1)) {
-	rex(0, 0, r1, r0, _NOREG);
+	rex(0, 0, r1, _NOREG, r0);
 	ic(0x88);
 	rx(r1, 0, r0, _NOREG, _SCL1);
     }
@@ -2367,7 +2367,7 @@ static void
 _str_s(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1)
 {
     ic(0x66);
-    rex(0, 0, r1, r0, _NOREG);
+    rex(0, 0, r1, _NOREG, r0);
     ic(0x89);
     rx(r1, 0, r0, _NOREG, _SCL1);
 }
@@ -2393,7 +2393,7 @@ _sti_s(jit_state_t *_jit, jit_word_t i0, jit_int32_t r0)
 static void
 _str_i(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1)
 {
-    rex(0, 0, r1, r0, _NOREG);
+    rex(0, 0, r1, _NOREG, r0);
     ic(0x89);
     rx(r1, 0, r0, _NOREG, _SCL1);
 }
@@ -2419,7 +2419,7 @@ _sti_i(jit_state_t *_jit, jit_word_t i0, jit_int32_t r0)
 static void
 _str_l(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1)
 {
-    rex(0, 1, r1, r0, _NOREG);
+    rex(0, 1, r1, _NOREG, r0);
     ic(0x89);
     rx(r1, 0, r0, _NOREG, _SCL1);
 }
@@ -2447,7 +2447,7 @@ _stxr_c(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1, jit_int32_t r2)
 {
     jit_int32_t		reg;
     if (reg8_p(r2)) {
-	rex(0, 0, r2, r0, r1);
+	rex(0, 0, r2, r1, r0);
 	ic(0x88);
 	rx(r2, 0, r0, r1, _SCL1);
     }
@@ -2490,7 +2490,7 @@ static void
 _stxr_s(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1, jit_int32_t r2)
 {
     ic(0x66);
-    rex(0, 0, r2, r0, r1);
+    rex(0, 0, r2, r1, r0);
     ic(0x89);
     rx(r2, 0, r0, r1, _SCL1);
 }
@@ -2516,7 +2516,7 @@ _stxi_s(jit_state_t *_jit, jit_word_t i0, jit_int32_t r0, jit_int32_t r1)
 static void
 _stxr_i(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1, jit_int32_t r2)
 {
-    rex(0, 0, r2, r0, r1);
+    rex(0, 0, r2, r1, r0);
     ic(0x89);
     rx(r2, 0, r0, r1, _SCL1);
 }
@@ -2542,7 +2542,7 @@ _stxi_i(jit_state_t *_jit, jit_word_t i0, jit_int32_t r0, jit_int32_t r1)
 static void
 _stxr_l(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1, jit_int32_t r2)
 {
-    rex(0, 1, r2, r0, r1);
+    rex(0, 1, r2, r1, r0);
     ic(0x89);
     rx(r2, 0, r0, r1, _SCL1);
 }