diff options
| author | Philippe Mathieu-Daudé <philmd@linaro.org> | 2024-04-30 13:10:19 +0200 |
|---|---|---|
| committer | Michael Tokarev <mjt@tls.msk.ru> | 2024-05-04 09:37:20 +0300 |
| commit | 30e8861a90a539ac23053de7645fc4b38e53130a (patch) | |
| tree | 7c4a0103e0aeb930c9b29bdcc664a612029f57a9 /tests | |
| parent | ea8665201987dab2550cd8b1d8c8c9da78dc2af5 (diff) | |
target/sh4: Fix SUBV opcode
The documentation says:
SUBV Rm, Rn Rn - Rm -> Rn, underflow -> T
The overflow / underflow can be calculated as:
T = ((Rn ^ Rm) & (Result ^ Rn)) >> 31
However we were using the incorrect:
T = ((Rn ^ Rm) & (Result ^ Rm)) >> 31
Fix by using the Rn register instead of Rm.
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>
Suggested-by: Paul Cercueil <paul@crapouillou.net>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2318
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: <20240430163125.77430-3-philmd@linaro.org>
(cherry picked from commit e88a856efd1d3c3ffa8e53da4831eff8da290808)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Diffstat (limited to 'tests')
| -rw-r--r-- | tests/tcg/sh4/Makefile.target | 3 | ||||
| -rw-r--r-- | tests/tcg/sh4/test-subv.c | 30 |
2 files changed, 33 insertions, 0 deletions
diff --git a/tests/tcg/sh4/Makefile.target b/tests/tcg/sh4/Makefile.target index 521b8b0a76..7852fa62d8 100644 --- a/tests/tcg/sh4/Makefile.target +++ b/tests/tcg/sh4/Makefile.target @@ -20,3 +20,6 @@ TESTS += test-macw test-addv: CFLAGS += -O -g TESTS += test-addv + +test-subv: CFLAGS += -O -g +TESTS += test-subv diff --git a/tests/tcg/sh4/test-subv.c b/tests/tcg/sh4/test-subv.c new file mode 100644 index 0000000000..a3c2db96e4 --- /dev/null +++ b/tests/tcg/sh4/test-subv.c @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#include <limits.h> +#include <stdio.h> +#include <stdlib.h> + +static void subv(const int a, const int b, const int res, const int carry) +{ + int o = a, c; + + asm volatile("subv %2,%0\n" + "movt %1\n" + : "+r"(o), "=r"(c) : "r"(b) : ); + + if (c != carry || o != res) { + printf("SUBV %d, %d = %d/%d [T = %d/%d]\n", a, b, o, res, c, carry); + abort(); + } +} + +int main(void) +{ + subv(INT_MIN, 1, INT_MAX, 1); + subv(INT_MAX, -1, INT_MIN, 1); + subv(INT_MAX, 1, INT_MAX - 1, 0); + subv(0, 1, -1, 0); + subv(-1, -1, 0, 0); + + return 0; +} |