On 1/15/24 20:14, Richard Henderson wrote:
On 1/16/24 09:25, Daniel Henrique Barboza wrote:
Signed-off-by: Daniel Henrique Barboza <dbarb...@ventanamicro.com>
---
target/riscv/cpu.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 11df226a00..7304e478c2 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -692,7 +692,11 @@ static inline uint32_t vext_get_vlmax(RISCVCPU *cpu,
target_ulong vtype)
{
uint8_t sew = FIELD_EX64(vtype, VTYPE, VSEW);
int8_t lmul = sextract32(FIELD_EX64(vtype, VTYPE, VLMUL), 0, 3);
- return cpu->cfg.vlen >> (sew + 3 - lmul);
+ /*
+ * vlmax = vlen >> (sew + 3 - lmul). With vlenb,
+ * 3 less shifts: vlenb >> (sew + 3 - 3 - lmul)
+ */
+ return cpu->cfg.vlenb >> (sew - lmul);
}
I take it back -- this doesn't work without the + 3:
sew = 0
lmul = 3
vlenb >> (0 - 3)
= vlenb >> -3
Need
vlen = vlenb << 3
vlmax = vlen >> (0 + 3 - 3)
= vlen >> 0
= vlen
I got tricked by the 'sew' variable name there. This formula is using vsew.
I'll fix and re-send. Thanks,
Daniel
r~