RVV spec allows implementations to set vl with values within
[ceil(AVL/2),VLMAX] when VLMAX < AVL < 2*VLMAX. This commit adds a
property "rvv_vl_half_avl" to enable setting vl = ceil(AVL/2). This
behavior helps identify compiler issues and bugs.
Signed-off-by: Jason Chien <jason.chien@sifive.com>
---
target/riscv/cpu.c | 1 +
target/riscv/cpu_cfg.h | 1 +
target/riscv/vector_helper.c | 2 ++
3 files changed, 4 insertions(+)
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index a90808a3ba..8f21171ffa 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -2687,6 +2687,7 @@ static Property riscv_cpu_properties[] = {
DEFINE_PROP_BOOL("rvv_ta_all_1s", RISCVCPU, cfg.rvv_ta_all_1s, false),
DEFINE_PROP_BOOL("rvv_ma_all_1s", RISCVCPU, cfg.rvv_ma_all_1s, false),
+ DEFINE_PROP_BOOL("rvv_vl_half_avl", RISCVCPU, cfg.rvv_vl_half_avl, false),
/*
* write_misa() is marked as experimental for now so mark
diff --git a/target/riscv/cpu_cfg.h b/target/riscv/cpu_cfg.h
index 8b272fb826..96fe26d4ea 100644
--- a/target/riscv/cpu_cfg.h
+++ b/target/riscv/cpu_cfg.h
@@ -127,6 +127,7 @@ struct RISCVCPUConfig {
bool ext_smepmp;
bool rvv_ta_all_1s;
bool rvv_ma_all_1s;
+ bool rvv_vl_half_avl;
uint32_t mvendorid;
uint64_t marchid;
diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
index 1b4d5a8e37..825312552b 100644
--- a/target/riscv/vector_helper.c
+++ b/target/riscv/vector_helper.c
@@ -75,6 +75,8 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
vlmax = vext_get_vlmax(cpu->cfg.vlenb, vsew, lmul);
if (s1 <= vlmax) {
vl = s1;
+ } else if (s1 < 2 * vlmax && cpu->cfg.rvv_vl_half_avl) {
+ vl = (s1 + 1) >> 1;
} else {
vl = vlmax;
}
--
2.43.2