target/sh4: Fix ADDV opcode

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>
Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Message-Id: <20240430163125.77430-2-philmd@linaro.org>

2 files changed, 30 insertions, 0 deletions

diff --git a/tests/tcg/sh4/Makefile.target b/tests/tcg/sh4/Makefile.target
index 4d09291c..521b8b0 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
diff --git a/tests/tcg/sh4/test-addv.c b/tests/tcg/sh4/test-addv.c
new file mode 100644
index 0000000..ca87fe7
--- /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 || o != 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;
+}