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| author | LIU Zhiwei <zhiwei_liu@c-sky.com> | 2021-02-12 23:02:21 +0800 |
|---|---|---|
| committer | Alistair Francis <alistair.francis@wdc.com> | 2021-05-11 20:02:06 +1000 |
| commit | 65606f21243a796537bfe4708720a9bf4bb50169 (patch) | |
| tree | 4eddd62d2c56a4f6f0e128fa40ec14871e2ebe95 | |
| parent | 11c27c6ded4d41bf0d100c8b5b49d5056204c911 (diff) | |
| download | qemu-65606f21243a796537bfe4708720a9bf4bb50169.zip qemu-65606f21243a796537bfe4708720a9bf4bb50169.tar.gz qemu-65606f21243a796537bfe4708720a9bf4bb50169.tar.bz2 | |
target/riscv: Fixup saturate subtract function
The overflow predication ((a - b) ^ a) & (a ^ b) & INT64_MIN is right.
However, when the predication is ture and a is 0, it should return maximum.
Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20210212150256.885-4-zhiwei_liu@c-sky.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
| -rw-r--r-- | target/riscv/vector_helper.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c index a156573..356cef8 100644 --- a/target/riscv/vector_helper.c +++ b/target/riscv/vector_helper.c @@ -2451,7 +2451,7 @@ static inline int8_t ssub8(CPURISCVState *env, int vxrm, int8_t a, int8_t b) { int8_t res = a - b; if ((res ^ a) & (a ^ b) & INT8_MIN) { - res = a > 0 ? INT8_MAX : INT8_MIN; + res = a >= 0 ? INT8_MAX : INT8_MIN; env->vxsat = 0x1; } return res; @@ -2461,7 +2461,7 @@ static inline int16_t ssub16(CPURISCVState *env, int vxrm, int16_t a, int16_t b) { int16_t res = a - b; if ((res ^ a) & (a ^ b) & INT16_MIN) { - res = a > 0 ? INT16_MAX : INT16_MIN; + res = a >= 0 ? INT16_MAX : INT16_MIN; env->vxsat = 0x1; } return res; @@ -2471,7 +2471,7 @@ static inline int32_t ssub32(CPURISCVState *env, int vxrm, int32_t a, int32_t b) { int32_t res = a - b; if ((res ^ a) & (a ^ b) & INT32_MIN) { - res = a > 0 ? INT32_MAX : INT32_MIN; + res = a >= 0 ? INT32_MAX : INT32_MIN; env->vxsat = 0x1; } return res; @@ -2481,7 +2481,7 @@ static inline int64_t ssub64(CPURISCVState *env, int vxrm, int64_t a, int64_t b) { int64_t res = a - b; if ((res ^ a) & (a ^ b) & INT64_MIN) { - res = a > 0 ? INT64_MAX : INT64_MIN; + res = a >= 0 ? INT64_MAX : INT64_MIN; env->vxsat = 0x1; } return res; |