Re: [Qemu-devel] [PATCH] RISCV: support riscv vector extension 0.7.1

[liuzhiwei]

On 2019/8/29 上午5:34, Alistair Francis wrote:
> On Wed, Aug 28, 2019 at 12:04 AM liuzhiwei <address@hidden> wrote:
> > Change-Id: I3cf891bc400713b95f47ecca82b1bf773f3dcb25
> > Signed-off-by: liuzhiwei <address@hidden>
> > ---
> >   fpu/softfloat.c                         |   119 +
> >   include/fpu/softfloat.h                 |     4 +
> >   linux-user/riscv/cpu_loop.c             |     8 +-
> >   target/riscv/Makefile.objs              |     2 +-
> >   target/riscv/cpu.h                      |    30 +
> >   target/riscv/cpu_bits.h                 |    15 +
> >   target/riscv/cpu_helper.c               |     7 +
> >   target/riscv/csr.c                      |    65 +-
> >   target/riscv/helper.h                   |   354 +
> >   target/riscv/insn32.decode              |   374 +-
> >   target/riscv/insn_trans/trans_rvv.inc.c |   484 +
> >   target/riscv/translate.c                |     1 +
> >   target/riscv/vector_helper.c            | 26563 ++++++++++++++++++++++++++++++
> >   13 files changed, 28017 insertions(+), 9 deletions(-)
> >   create mode 100644 target/riscv/insn_trans/trans_rvv.inc.c
> >   create mode 100644 target/riscv/vector_helper.c
> Hello,
>
> Thanks for the patch!
>
> As others have pointed out you will need to split the patch up into
> multiple smaller patches, otherwise it is too hard to review almost
> 30,000 lines of code.

Hi, Alistair

I'm so sorry for the inconvenience. It will be a patch set with a cover 
letter in V2.

> Can you also include a cover letter with your patch series describing
> how you are testing this? AFAIK vector extension support isn't in any
> compiler so I'm assuming you are handwriting the assembly or have
> toolchain patches. Either way it will help if you can share that so
> others can test your implementation.

Yes, it's handwriting assembly. The assembler in Binutils has support 
Vector extension.  First define an function test_vadd_vv_8 in assembly 
and then it can be called from a C program.

The function is something like

/* vadd.vv */
TEST_FUNC(test_vadd_vv_8)
        vsetvli        t1, x0, e8, m2
        vlb.v           v6, (a4)
        vsb.v           v6, (a3)
        vsetvli        t1, a0, e8, m2
        vlb.v           v0, (a1)
        vlb.v           v2, (a2)
        vadd.vv     v4, v0, v2
        vsb.v          v4, (a3)
ret
        .size   test_vadd_vv_8, .-test_vadd_vv_8

It takes more time to test than to implement the instructions. Maybe 
there is some better test method or some forced test cases in QEMU. 
Could you give me some advice for testing?

Best Regards,

Zhiwei

> Alex and Richard have kindly started the review. Once you have
> addressed their comments and split this patch up into smaller patches
> you can send a v2 and we can go from there.
>
> Once again thanks for doing this implementation for QEMU!
>
> Alistair