Re: [PATCH qemu 00/13] Add tail agnostic behavior for rvv instructions

[Weiwei Li]

在 2022/3/19 下午8:50, ~eopxd 写道:
> According to v-spec, tail agnostic behavior can be either kept as
> undisturbed or set elements' bits to all 1s. To distinguish the
> difference of tail policies, qemu should be able to simulate the tail
> agnostic behavior as "set tail elements' bits to all 1s". An option
> 'rvv_ta_all_1s' is added to enable the behavior, it is default as
> disabled.

Another question: when rvv_ta_all_1s for vta  is enabled, How about vma? 
Is it necessary to set the inactive elements to all 1s?

Regards,

Weiwei Li

> eopXD (13):
>    target/riscv: rvv: Prune redundant ESZ, DSZ parameter passed
>    target/riscv: rvv: Rename ambiguous esz
>    target/riscv: rvv: Early exit when vstart >= vl
>    target/riscv: rvv: Add tail agnostic for vv instructions
>    target/riscv: rvv: Add tail agnostic for vx, vvm, vxm instructions
>    target/riscv: rvv: Add tail agnostic for vector integer shift
>      instructions
>    target/riscv: rvv: Add tail agnostic for vector integer comparison
>      instructions
>    target/riscv: rvv: Add tail agnostic for vector integer merge and move
>      instructions
>    target/riscv: rvv: Add tail agnostic for vector fix-point arithmetic
>      instructions
>    target/riscv: rvv: Add tail agnostic for vector floating-point
>      instructions
>    target/riscv: rvv: Add tail agnostic for vector reduction instructions
>    target/riscv: rvv: Add tail agnostic for vector mask instructions
>    target/riscv: rvv: Add tail agnostic for vector permutation
>      instructions
>
>   target/riscv/cpu.c                      |    1 +
>   target/riscv/cpu.h                      |    2 +
>   target/riscv/cpu_helper.c               |    2 +
>   target/riscv/insn_trans/trans_rvv.c.inc |   58 +
>   target/riscv/internals.h                |    5 +-
>   target/riscv/translate.c                |    2 +
>   target/riscv/vector_helper.c            | 1508 ++++++++++++++---------
>   7 files changed, 961 insertions(+), 617 deletions(-)