diff --git a/tests/xtensa/Makefile b/tests/xtensa/Makefile
index 70bd097..15d39da 100644
--- a/tests/xtensa/Makefile
+++ b/tests/xtensa/Makefile
@@ -28,6 +28,7 @@
 TESTCASES += test_fail.tst
 TESTCASES += test_interrupt.tst
 TESTCASES += test_loop.tst
+TESTCASES += test_mac16.tst
 TESTCASES += test_max.tst
 TESTCASES += test_min.tst
 TESTCASES += test_mmu.tst
diff --git a/tests/xtensa/test_mac16.S b/tests/xtensa/test_mac16.S
new file mode 100644
index 0000000..5ddd160
--- /dev/null
+++ b/tests/xtensa/test_mac16.S
@@ -0,0 +1,243 @@
+.include "macros.inc"
+
+test_suite mac16
+
+#define ext16(v) (((v) & 0xffff) | (((v) & 0x8000) * 0x1ffffffe))
+#define mul16(a, b) ((ext16(a) * ext16(b)))
+
+.macro assert_acc_value v
+    rsr     a4, ACCLO
+    movi    a5, (\v) & 0xffffffff
+    assert  eq, a4, a5
+    rsr     a4, ACCHI
+    movi    a5, (\v) >> 32
+    sext    a5, a5, 7
+    assert  eq, a4, a5
+.endm
+
+.macro init_reg sr, reg, val
+    .if (\sr)
+    movi    a4, \val
+    wsr     a4, \reg
+    .else
+    movi    \reg, \val
+    .endif
+.endm
+
+.macro test_mulxx mulop, comb, s, t, a, b
+    init_reg \comb & 2, \s, \a
+    init_reg \comb & 1, \t, \b
+
+    \mulop\().ll \s, \t
+    assert_acc_value mul16(\a, \b)
+
+    \mulop\().lh \s, \t
+    assert_acc_value mul16(\a, (\b >> 16))
+
+    \mulop\().hl \s, \t
+    assert_acc_value mul16((\a >> 16), \b)
+
+    \mulop\().hh \s, \t
+    assert_acc_value mul16((\a >> 16), (\b >> 16))
+.endm
+
+test mul_aa
+    test_mulxx mul.aa, 0, a2, a3, 0xf7315a5a, 0xa5a5137f
+test_end
+
+test mul_ad
+    test_mulxx mul.ad, 1, a2, m2, 0xf7315a5a, 0xa5a5137f
+test_end
+
+test mul_da
+    test_mulxx mul.da, 2, m1, a3, 0xf7315a5a, 0xa5a5137f
+test_end
+
+test mul_dd
+    test_mulxx mul.dd, 3, m0, m3, 0xf7315a5a, 0xa5a5137f
+test_end
+
+
+.macro init_acc iv
+    movi    a4, (\iv) & 0xffffffff
+    wsr     a4, ACCLO
+    movi    a4, (\iv) >> 32
+    wsr     a4, ACCHI
+.endm
+
+.macro test_mulxxx mulop, comb, s, t, a, b, iv, op
+    init_reg \comb & 2, \s, \a
+    init_reg \comb & 1, \t, \b
+
+    init_acc \iv
+    \mulop\().ll \s, \t
+    assert_acc_value (\iv \op mul16(\a, \b))
+
+    init_acc \iv
+    \mulop\().lh \s, \t
+    assert_acc_value (\iv \op mul16(\a, (\b >> 16)))
+
+    init_acc \iv
+    \mulop\().hl \s, \t
+    assert_acc_value (\iv \op mul16((\a >> 16), \b))
+
+    init_acc \iv
+    \mulop\().hh \s, \t
+    assert_acc_value (\iv \op mul16((\a >> 16), (\b >> 16)))
+.endm
+
+
+test mula_aa
+    test_mulxxx mula.aa, 0, a2, a3, 0xf7315a5a, 0xa5a5137f, 0xfff73155aa, +
+test_end
+
+test mula_ad
+    test_mulxxx mula.ad, 1, a2, m2, 0xf7315a5a, 0xa5a5137f, 0xfff73155aa, +
+test_end
+
+test mula_da
+    test_mulxxx mula.da, 2, m1, a3, 0xf7315a5a, 0xa5a5137f, 0x0ff73155aa, +
+test_end
+
+test mula_dd
+    test_mulxxx mula.dd, 3, m0, m3, 0xf7315a5a, 0xa5a5137f, 0x0ff73155aa, +
+test_end
+
+
+test muls_aa
+    test_mulxxx muls.aa, 0, a2, a3, 0xf7315a5a, 0xa5a5137f, 0x0ff73155aa, -
+test_end
+
+test muls_ad
+    test_mulxxx muls.ad, 1, a2, m2, 0xf7315a5a, 0xa5a5137f, 0x0ff73155aa, -
+test_end
+
+test muls_da
+    test_mulxxx muls.da, 2, m1, a3, 0xf7315a5a, 0xa5a5137f, 0xfff73155aa, -
+test_end
+
+test muls_dd
+    test_mulxxx muls.dd, 3, m0, m3, 0xf7315a5a, 0xa5a5137f, 0xfff73155aa, -
+test_end
+
+test ldinc
+    movi    a2, 1f - 4
+    ldinc   m0, a2
+    movi    a3, 1f
+    assert  eq, a2, a3
+    rsr     a3, m0
+    movi    a4, 0x55aa137f
+    assert  eq, a3, a4
+    ldinc   m1, a2
+    movi    a3, 1f + 4
+    assert  eq, a2, a3
+    rsr     a3, m1
+    movi    a4, 0x12345678
+    assert  eq, a3, a4
+
+.data
+1:  .word 0x55aa137f, 0x12345678, 0x137fa5a5
+.text
+test_end
+
+test lddec
+    movi    a2, 1f
+    lddec   m2, a2
+    movi    a3, 1f - 4
+    assert  eq, a2, a3
+    rsr     a3, m2
+    movi    a4, 0x12345678
+    assert  eq, a3, a4
+    lddec   m3, a2
+    movi    a3, 1f - 8
+    assert  eq, a2, a3
+    rsr     a3, m3
+    movi    a4, 0x55aa137f
+    assert  eq, a3, a4
+.data
+    .word 0x55aa137f, 0x12345678
+1:
+.text
+test_end
+
+
+.macro test_mulxxx_ld mulop, ldop, comb, w, x, s, t, a, b, iv, op
+    init_reg \comb & 2, \s, \a
+    init_reg \comb & 1, \t, \b
+
+    init_acc \iv
+    \mulop\().ll.\ldop \w, \x, \s, \t
+    assert_acc_value (\iv \op mul16(\a, \b))
+
+    init_acc \iv
+    \mulop\().lh.\ldop \w, \x, \s, \t
+    assert_acc_value (\iv \op mul16(\a, (\b >> 16)))
+
+    init_acc \iv
+    \mulop\().hl.\ldop \w, \x, \s, \t
+    assert_acc_value (\iv \op mul16((\a >> 16), \b))
+
+    init_acc \iv
+    \mulop\().hh.\ldop \w, \x, \s, \t
+    assert_acc_value (\iv \op mul16((\a >> 16), (\b >> 16)))
+.endm
+
+test mula_da_ldinc
+    movi    a2, 1f - 4
+    test_mulxxx_ld mula.da, ldinc, 2, m1, a2, m1, a3, \
+        0xf7315a5a, 0xa5a5137f, 0x0ff73155aa, +
+    movi    a3, 1f + 12
+    assert  eq, a2, a3
+    rsr     a2, m1
+    movi    a3, 0x12345678
+    assert  eq, a2, a3
+.data
+1:  .word 0xf7315a5a, 0xf7315a5a, 0xf7315a5a, 0x12345678
+.text
+test_end
+
+test mula_dd_ldinc
+    movi    a2, 1f - 4
+    test_mulxxx_ld mula.dd, ldinc, 3, m2, a2, m1, m2, \
+        0xf7315a5a, 0xa5a5137f, 0x0ff73155aa, +
+    movi    a3, 1f + 12
+    assert  eq, a2, a3
+    rsr     a2, m2
+    movi    a3, 0x12345678
+    assert  eq, a2, a3
+.data
+1:  .word 0xa5a5137f, 0xa5a5137f, 0xa5a5137f, 0x12345678
+.text
+test_end
+
+test mula_da_lddec
+    movi    a2, 1f
+    test_mulxxx_ld mula.da, lddec, 2, m1, a2, m1, a3, \
+        0xf7315a5a, 0xa5a5137f, 0x0ff73155aa, +
+    movi    a3, 1f - 16
+    assert  eq, a2, a3
+    rsr     a2, m1
+    movi    a3, 0x12345678
+    assert  eq, a2, a3
+.data
+    .word 0x12345678, 0xf7315a5a, 0xf7315a5a, 0xf7315a5a
+1:
+.text
+test_end
+
+test mula_dd_lddec
+    movi    a2, 1f
+    test_mulxxx_ld mula.dd, lddec, 3, m2, a2, m1, m2, \
+        0xf7315a5a, 0xa5a5137f, 0x0ff73155aa, +
+    movi    a3, 1f - 16
+    assert  eq, a2, a3
+    rsr     a2, m2
+    movi    a3, 0x12345678
+    assert  eq, a2, a3
+.data
+    .word 0x12345678, 0xa5a5137f, 0xa5a5137f, 0xa5a5137f
+1:
+.text
+test_end
+
+test_suite_end