Re: [PATCH v6 09/14] target/riscv: rvk: add support for sha512 related instructions for RV32 in zknh extension

[Weiwei Li]

在 2022/2/28 上午3:36, Richard Henderson 写道:
> On 2/27/22 04:25, Weiwei Li wrote:
> >   - add sha512sum0r, sha512sig0l, sha512sum1r, sha512sig1l, 
> > sha512sig0h and sha512sig1h instructions
> >
> > Co-authored-by: Zewen Ye <lustrew@foxmail.com>
> > Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
> > Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
> > ---
> >   target/riscv/crypto_helper.c            | 57 ++++++++++++++++
> >   target/riscv/helper.h                   |  7 ++
> >   target/riscv/insn32.decode              |  6 ++
> >   target/riscv/insn_trans/trans_rvk.c.inc | 90 +++++++++++++++++++++++++
> >   4 files changed, 160 insertions(+)
> >
> > diff --git a/target/riscv/crypto_helper.c b/target/riscv/crypto_helper.c
> > index f5ffc262f2..6cd2a92b86 100644
> > --- a/target/riscv/crypto_helper.c
> > +++ b/target/riscv/crypto_helper.c
> > @@ -303,4 +303,61 @@ target_ulong HELPER(sha256sum1)(target_ulong rs1)
> >       return sext_xlen(ROR32(a, 6) ^ ROR32(a, 11) ^ ROR32(a, 25));
> >   }
> >   #undef ROR32
> > +
> > +#define zext32(x) ((uint64_t)(uint32_t)(x))
> > +
> > +target_ulong HELPER(sha512sum0r)(target_ulong rs1, target_ulong rs2)
> > +{
> > +    uint64_t result = (zext32(rs1) << 25) ^ (zext32(rs1) << 30) ^
> > +                      (zext32(rs1) >> 28) ^ (zext32(rs2) >> 7) ^
> > +                      (zext32(rs2) >> 2) ^ (zext32(rs2) << 4);
> > +
> > +    return sext_xlen(result);
> > +}
>
> I'm a little confused as to why you're extending back to uint64_t?  
> Especially since the top 32 are discarded.
>
> Also, I think sext_xlen is a bad name -- sext32_xlen would be better.  
> It confused me here for a bit, and I went off on a bit of an 
> irrelevant tangent.
>
> These could also be implemented inline.  I count 12 instructions. The 
> overhead of a function call is about 7.
Yeah. It's not necessary to extend to uint64_t.  I'll try to change them 
to inline later.
> > +DEF_HELPER_2(sha512sum0r, tl, tl, tl)
> > +DEF_HELPER_2(sha512sum1r, tl, tl, tl)
> > +DEF_HELPER_2(sha512sig0l, tl, tl, tl)
> > +DEF_HELPER_2(sha512sig0h, tl, tl, tl)
> > +DEF_HELPER_2(sha512sig1l, tl, tl, tl)
> > +DEF_HELPER_2(sha512sig1h, tl, tl, tl)
>
> DEF_HELPER_FLAGS.
>
> > +static bool trans_sha512sum0r(DisasContext *ctx, arg_sha512sum0r *a)
> > +{
> > +    REQUIRE_32BIT(ctx);
> > +    REQUIRE_ZKNH(ctx);
> > +
> > +    TCGv dest = dest_gpr(ctx, a->rd);
> > +    TCGv src1 = get_gpr(ctx, a->rs1, EXT_NONE);
> > +    TCGv src2 = get_gpr(ctx, a->rs2, EXT_NONE);
> > +
> > +    gen_helper_sha512sum0r(dest, src1, src2);
> > +    gen_set_gpr(ctx, a->rd, dest);
> > +
> > +    return true;
> > +}
>
> gen_arith.
OK. I'll fix them.

Regards,

Weiwei Li

> r~