[PATCH v4 1/4] target/sh4: Fix ADDV opcode

[Philippe Mathieu-Daudé]

The documentation says:

  ADDV Rm, Rn        Rn + Rm -> Rn, overflow -> T

But QEMU implementation was:

  ADDV Rm, Rn        Rn + Rm -> Rm, overflow -> T

Fix by filling the correct Rm register.

Add tests provided by Paul Cercueil.

Cc: qemu-stable@nongnu.org
Fixes: ad8d25a11f ("target-sh4: implement addv and subv using TCG")
Reported-by: Paul Cercueil <paul@crapouillou.net>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2317
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 target/sh4/translate.c        |  2 +-
 tests/tcg/sh4/test-addv.c     | 27 +++++++++++++++++++++++++++
 tests/tcg/sh4/Makefile.target |  3 +++
 3 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 tests/tcg/sh4/test-addv.c

diff --git a/target/sh4/translate.c b/target/sh4/translate.c
index ebb6c901bf..4a1dd0d1f4 100644
--- a/target/sh4/translate.c
+++ b/target/sh4/translate.c
@@ -714,7 +714,7 @@ static void _decode_opc(DisasContext * ctx)
             tcg_gen_xor_i32(t2, REG(B7_4), REG(B11_8));
             tcg_gen_andc_i32(cpu_sr_t, t1, t2);
             tcg_gen_shri_i32(cpu_sr_t, cpu_sr_t, 31);
-            tcg_gen_mov_i32(REG(B7_4), t0);
+            tcg_gen_mov_i32(REG(B11_8), t0);
         }
         return;
     case 0x2009: /* and Rm,Rn */
diff --git a/tests/tcg/sh4/test-addv.c b/tests/tcg/sh4/test-addv.c
new file mode 100644
index 0000000000..64f709161f
--- /dev/null
+++ b/tests/tcg/sh4/test-addv.c
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static void addv(const int a, const int b, const int res, const int carry)
+{
+    int o = a, c;
+
+    asm volatile("addv %2,%0\n"
+                 "movt %1\n"
+                 : "+r"(o), "=r"(c) : "r"(b) :);
+
+    if (c != carry || aw != res) {
+        printf("ADDV %d, %d = %d/%d [T = %d/%d]\n", a, b, o, res, c, carry);
+        abort();
+    }
+}
+
+int main(void)
+{
+    addv(INT_MAX, 1, INT_MIN, 1);
+    addv(INT_MAX - 1, 1, INT_MAX, 0);
+
+    return 0;
+}
diff --git a/tests/tcg/sh4/Makefile.target b/tests/tcg/sh4/Makefile.target
index 4d09291c0c..521b8b0a76 100644
--- a/tests/tcg/sh4/Makefile.target
+++ b/tests/tcg/sh4/Makefile.target
@@ -17,3 +17,6 @@ TESTS += test-macl
 
 test-macw: CFLAGS += -O -g
 TESTS += test-macw
+
+test-addv: CFLAGS += -O -g
+TESTS += test-addv
-- 
2.41.0