target/riscv/vector_helper.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
The previous check was failing with:
VLEN=128 ELEN = 64 SEW = 16 and LMUL = 1/8 which is a
valid combination.
Fix the check to allow valid combinations when VLEN is a multiple of
ELEN.
From the specification:
"In general, the requirement is to support LMUL ≥ SEWMIN/ELEN, where
SEWMIN is the narrowest supported SEW value and ELEN is the widest
supported SEW value. In the standard extensions, SEWMIN=8. For standard
vector extensions with ELEN=32, fractional LMULs of 1/2 and 1/4 must be
supported. For standard vector extensions with ELEN=64, fractional LMULs
of 1/2, 1/4, and 1/8 must be supported." Elsewhere in the specification
it makes clear that VLEN>=ELEN.
From inspection this new check allows:
VLEN=ELEN=64 1/2, 1/4, 1/8 for SEW >=8
VLEN=ELEN=32 1/2, 1/4 for SEW >=8
Fixes: d9b7609a1fb2 ("target/riscv: rvv-1.0: configure instructions")
Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
---
V2: Switch check to use VLEN and active SEW vs ELEN and minimum SEW
---
target/riscv/vector_helper.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
index cfacf2ebba..4d06754826 100644
--- a/target/riscv/vector_helper.c
+++ b/target/riscv/vector_helper.c
@@ -43,9 +43,9 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
xlen - 1 - R_VTYPE_RESERVED_SHIFT);
if (lmul & 4) {
- /* Fractional LMUL. */
+ /* Fractional LMUL - check LMUL * VLEN >= SEW */
if (lmul == 4 ||
- cpu->cfg.elen >> (8 - lmul) < sew) {
+ cpu->cfg.vlen >> (8 - lmul) < sew) {
vill = true;
}
}
--
2.41.0
On Tue, Jul 18, 2023 at 11:14 PM Rob Bradford <rbradford@rivosinc.com> wrote: > > The previous check was failing with: > > VLEN=128 ELEN = 64 SEW = 16 and LMUL = 1/8 which is a > valid combination. > > Fix the check to allow valid combinations when VLEN is a multiple of > ELEN. > > From the specification: > > "In general, the requirement is to support LMUL ≥ SEWMIN/ELEN, where > SEWMIN is the narrowest supported SEW value and ELEN is the widest > supported SEW value. In the standard extensions, SEWMIN=8. For standard > vector extensions with ELEN=32, fractional LMULs of 1/2 and 1/4 must be > supported. For standard vector extensions with ELEN=64, fractional LMULs > of 1/2, 1/4, and 1/8 must be supported." Elsewhere in the specification > it makes clear that VLEN>=ELEN. > > From inspection this new check allows: > > VLEN=ELEN=64 1/2, 1/4, 1/8 for SEW >=8 > VLEN=ELEN=32 1/2, 1/4 for SEW >=8 > > Fixes: d9b7609a1fb2 ("target/riscv: rvv-1.0: configure instructions") > > Signed-off-by: Rob Bradford <rbradford@rivosinc.com> Thanks! Applied to riscv-to-apply.next Alistair > --- > V2: Switch check to use VLEN and active SEW vs ELEN and minimum SEW > --- > target/riscv/vector_helper.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c > index cfacf2ebba..4d06754826 100644 > --- a/target/riscv/vector_helper.c > +++ b/target/riscv/vector_helper.c > @@ -43,9 +43,9 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1, > xlen - 1 - R_VTYPE_RESERVED_SHIFT); > > if (lmul & 4) { > - /* Fractional LMUL. */ > + /* Fractional LMUL - check LMUL * VLEN >= SEW */ > if (lmul == 4 || > - cpu->cfg.elen >> (8 - lmul) < sew) { > + cpu->cfg.vlen >> (8 - lmul) < sew) { > vill = true; > } > } > -- > 2.41.0 > >
On 2023/7/18 21:11, Rob Bradford wrote: > The previous check was failing with: > > VLEN=128 ELEN = 64 SEW = 16 and LMUL = 1/8 which is a > valid combination. > > Fix the check to allow valid combinations when VLEN is a multiple of > ELEN. > > From the specification: > > "In general, the requirement is to support LMUL ≥ SEWMIN/ELEN, where > SEWMIN is the narrowest supported SEW value and ELEN is the widest > supported SEW value. In the standard extensions, SEWMIN=8. For standard > vector extensions with ELEN=32, fractional LMULs of 1/2 and 1/4 must be > supported. For standard vector extensions with ELEN=64, fractional LMULs > of 1/2, 1/4, and 1/8 must be supported." Elsewhere in the specification > it makes clear that VLEN>=ELEN. > > From inspection this new check allows: > > VLEN=ELEN=64 1/2, 1/4, 1/8 for SEW >=8 > VLEN=ELEN=32 1/2, 1/4 for SEW >=8 > > Fixes: d9b7609a1fb2 ("target/riscv: rvv-1.0: configure instructions") > > Signed-off-by: Rob Bradford <rbradford@rivosinc.com> > --- > V2: Switch check to use VLEN and active SEW vs ELEN and minimum SEW > --- Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn> Weiwei Li > target/riscv/vector_helper.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c > index cfacf2ebba..4d06754826 100644 > --- a/target/riscv/vector_helper.c > +++ b/target/riscv/vector_helper.c > @@ -43,9 +43,9 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1, > xlen - 1 - R_VTYPE_RESERVED_SHIFT); > > if (lmul & 4) { > - /* Fractional LMUL. */ > + /* Fractional LMUL - check LMUL * VLEN >= SEW */ > if (lmul == 4 || > - cpu->cfg.elen >> (8 - lmul) < sew) { > + cpu->cfg.vlen >> (8 - lmul) < sew) { > vill = true; > } > }
© 2016 - 2024 Red Hat, Inc.