On 1/24/25 7:14 AM, Max Chou wrote:
According to the Vector Reduction Operations section in the RISC-V "V"
Vector Extension spec,
"If vl=0, no operation is performed and the destination register is not
updated."
The vd should be updated when vl is larger than 0.
Fixes: fe5c9ab1fc ("target/riscv: vector single-width integer reduction
instructions")
Fixes: f714361ed7 ("target/riscv: rvv-1.0: implement vstart CSR")
Signed-off-by: Max Chou <max.c...@sifive.com>
Reviewed-by: Daniel Henrique Barboza <dbarb...@ventanamicro.com>
---
target/riscv/vector_helper.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
index 5386e3b97c5..7773df6a7c7 100644
--- a/target/riscv/vector_helper.c
+++ b/target/riscv/vector_helper.c
@@ -4659,7 +4659,9 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1,
\
} \
s1 = OP(s1, (TD)s2); \
} \
- *((TD *)vd + HD(0)) = s1; \
+ if (vl > 0) { \
+ *((TD *)vd + HD(0)) = s1; \
+ } \
env->vstart = 0; \
/* set tail elements to 1s */ \
vext_set_elems_1s(vd, vta, esz, vlenb); \
@@ -4745,7 +4747,9 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1,
\
} \
s1 = OP(s1, (TD)s2, &env->fp_status); \
} \
- *((TD *)vd + HD(0)) = s1; \
+ if (vl > 0) { \
+ *((TD *)vd + HD(0)) = s1; \
+ } \
env->vstart = 0; \
/* set tail elements to 1s */ \
vext_set_elems_1s(vd, vta, esz, vlenb); \
