Re: [PATCH 06/39] target/riscv: Add vrol.[vv, vx] and vror.[vv, vx, vi] decoding, translation and execution support

[Philipp Tomsich]

On Thu, 2 Feb 2023 at 13:42, Lawrence Hunter
<lawrence.hunter@codethink.co.uk> wrote:
>
> From: Dickon Hood <dickon.hood@codethink.co.uk>
>
> Add an initial implementation of the vrol.* and vror.* instructions,
> with mappings between the RISC-V instructions and their internal TCG
> accelerated implmentations.
>
> There are some missing ror helpers, so I've bodged it by converting them
> to rols.
>
> Co-authored-by: Kiran Ostrolenk <kiran.ostrolenk@codethink.co.uk>
> Signed-off-by: Kiran Ostrolenk <kiran.ostrolenk@codethink.co.uk>
> Signed-off-by: Dickon Hood <dickon.hood@codethink.co.uk>
> ---
>  target/riscv/helper.h                      | 20 ++++++++
>  target/riscv/insn32.decode                 |  6 +++
>  target/riscv/insn_trans/trans_rvzvkb.c.inc | 20 ++++++++
>  target/riscv/vcrypto_helper.c              | 58 ++++++++++++++++++++++
>  target/riscv/vector_helper.c               | 45 -----------------
>  target/riscv/vector_internals.h            | 52 +++++++++++++++++++
>  6 files changed, 156 insertions(+), 45 deletions(-)
>
> diff --git a/target/riscv/helper.h b/target/riscv/helper.h
> index 32f1179e29..e5b6b3360f 100644
> --- a/target/riscv/helper.h
> +++ b/target/riscv/helper.h
> @@ -1142,3 +1142,23 @@ DEF_HELPER_6(vclmul_vv, void, ptr, ptr, ptr, ptr, env, 
> i32)
>  DEF_HELPER_6(vclmul_vx, void, ptr, ptr, tl, ptr, env, i32)
>  DEF_HELPER_6(vclmulh_vv, void, ptr, ptr, ptr, ptr, env, i32)
>  DEF_HELPER_6(vclmulh_vx, void, ptr, ptr, tl, ptr, env, i32)
> +
> +DEF_HELPER_6(vror_vv_b, void, ptr, ptr, ptr, ptr, env, i32)
> +DEF_HELPER_6(vror_vv_h, void, ptr, ptr, ptr, ptr, env, i32)
> +DEF_HELPER_6(vror_vv_w, void, ptr, ptr, ptr, ptr, env, i32)
> +DEF_HELPER_6(vror_vv_d, void, ptr, ptr, ptr, ptr, env, i32)
> +
> +DEF_HELPER_6(vror_vx_b, void, ptr, ptr, tl, ptr, env, i32)
> +DEF_HELPER_6(vror_vx_h, void, ptr, ptr, tl, ptr, env, i32)
> +DEF_HELPER_6(vror_vx_w, void, ptr, ptr, tl, ptr, env, i32)
> +DEF_HELPER_6(vror_vx_d, void, ptr, ptr, tl, ptr, env, i32)
> +
> +DEF_HELPER_6(vrol_vv_b, void, ptr, ptr, ptr, ptr, env, i32)
> +DEF_HELPER_6(vrol_vv_h, void, ptr, ptr, ptr, ptr, env, i32)
> +DEF_HELPER_6(vrol_vv_w, void, ptr, ptr, ptr, ptr, env, i32)
> +DEF_HELPER_6(vrol_vv_d, void, ptr, ptr, ptr, ptr, env, i32)
> +
> +DEF_HELPER_6(vrol_vx_b, void, ptr, ptr, tl, ptr, env, i32)
> +DEF_HELPER_6(vrol_vx_h, void, ptr, ptr, tl, ptr, env, i32)
> +DEF_HELPER_6(vrol_vx_w, void, ptr, ptr, tl, ptr, env, i32)
> +DEF_HELPER_6(vrol_vx_d, void, ptr, ptr, tl, ptr, env, i32)
> diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
> index b4d88dd1cb..725f907ad1 100644
> --- a/target/riscv/insn32.decode
> +++ b/target/riscv/insn32.decode
> @@ -896,3 +896,9 @@ vclmul_vv       001100 . ..... ..... 010 ..... 1010111 
> @r_vm
>  vclmul_vx       001100 . ..... ..... 110 ..... 1010111 @r_vm
>  vclmulh_vv      001101 . ..... ..... 010 ..... 1010111 @r_vm
>  vclmulh_vx      001101 . ..... ..... 110 ..... 1010111 @r_vm
> +vrol_vv         010101 . ..... ..... 000 ..... 1010111 @r_vm
> +vrol_vx         010101 . ..... ..... 100 ..... 1010111 @r_vm
> +vror_vv         010100 . ..... ..... 000 ..... 1010111 @r_vm
> +vror_vx         010100 . ..... ..... 100 ..... 1010111 @r_vm
> +vror_vi         010100 . ..... ..... 011 ..... 1010111 @r_vm
> +vror_vi2        010101 . ..... ..... 011 ..... 1010111 @r_vm

We have only a single vror_vi instruction... and it has a 6bit immediate.
There's no need to deviate from the spec. Just write it as follows:
%imm_z6   26:1 15:5
@r2_zimm6  ..... . vm:1 ..... ..... ... ..... .......  &rmrr %rs2
rs1=%imm_z6 %rd
vror_vi         01010. . ..... ..... 011 ..... 1010111 @r2_zimm6

> diff --git a/target/riscv/insn_trans/trans_rvzvkb.c.inc 
> b/target/riscv/insn_trans/trans_rvzvkb.c.inc
> index 533141e559..d2a7a92d42 100644
> --- a/target/riscv/insn_trans/trans_rvzvkb.c.inc
> +++ b/target/riscv/insn_trans/trans_rvzvkb.c.inc
> @@ -95,3 +95,23 @@ static bool vclmul_vx_check(DisasContext *s, arg_rmrr *a)
>
>  GEN_VX_MASKED_TRANS(vclmul_vx, vclmul_vx_check)
>  GEN_VX_MASKED_TRANS(vclmulh_vx, vclmul_vx_check)
> +
> +GEN_OPIVV_TRANS(vror_vv, zvkb_vv_check)
> +GEN_OPIVX_TRANS(vror_vx, zvkb_vx_check)
> +GEN_OPIVV_TRANS(vrol_vv, zvkb_vv_check)
> +GEN_OPIVX_TRANS(vrol_vx, zvkb_vx_check)
> +
> +GEN_OPIVI_TRANS(vror_vi, IMM_TRUNC_SEW, vror_vx, zvkb_vx_check)

Please introduce a IMM_ZIMM6 that integrates with the extract_imm as follows:
    case IMM_ZIMM6:
        return extract64(imm, 0, 6);

> +
> +/*
> + * Immediates are 5b long, and we need six for the rotate-immediate.  The
> + * decision has been taken to remove the vrol.vi instruction -- you can
> + * emulate it with a ror, after all -- and use the bottom bit of the funct6
> + * part of the opcode to encode the extra bit.  I've chosen to implement it
> + * like this because it's easy and reasonably clean.
> + */
> +static bool trans_vror_vi2(DisasContext *s, arg_rmrr *a)
> +{
> +    a->rs1 += 32;
> +    return trans_vror_vi(s, a);
> +}

As discussed above, please handle this in a single trans_vror_vi:
   GEN_OPIVI_GVEC_TRANS_CHECK(vror_vi, IMM_ZIMM6, vror_vx, rotri, zvkb_check_vi)

> diff --git a/target/riscv/vcrypto_helper.c b/target/riscv/vcrypto_helper.c
> index 46e2e510c5..7ec75c5589 100644
> --- a/target/riscv/vcrypto_helper.c
> +++ b/target/riscv/vcrypto_helper.c
> @@ -57,3 +57,61 @@ GEN_VEXT_VV(vclmul_vv, 8)
>  GEN_VEXT_VX(vclmul_vx, 8)
>  GEN_VEXT_VV(vclmulh_vv, 8)
>  GEN_VEXT_VX(vclmulh_vx, 8)
> +
> +/*
> + *  Looks a mess, but produces reasonable (aarch32) code on clang:
> + * https://godbolt.org/z/jchjsTda8
> + */
> +#define DO_ROR(x, n)                       \
> +    ((x >> (n & ((sizeof(x) << 3) - 1))) | \
> +     (x << ((sizeof(x) << 3) - (n & ((sizeof(x) << 3) - 1)))))
> +#define DO_ROL(x, n)                       \
> +    ((x << (n & ((sizeof(x) << 3) - 1))) | \
> +     (x >> ((sizeof(x) << 3) - (n & ((sizeof(x) << 3) - 1)))))
> +
> +RVVCALL(OPIVV2, vror_vv_b, OP_UUU_B, H1, H1, H1, DO_ROR)
> +RVVCALL(OPIVV2, vror_vv_h, OP_UUU_H, H2, H2, H2, DO_ROR)
> +RVVCALL(OPIVV2, vror_vv_w, OP_UUU_W, H4, H4, H4, DO_ROR)
> +RVVCALL(OPIVV2, vror_vv_d, OP_UUU_D, H8, H8, H8, DO_ROR)

Indeed, this is a mess: we already have ror8/16/32/64 available.
Why not the following?

/* vror.vv */
GEN_VEXT_SHIFT_VV(vror_vv_b, uint8_t,  uint8_t,  H1, H1, ror8,  0x7)
GEN_VEXT_SHIFT_VV(vror_vv_h, uint16_t, uint16_t, H2, H2, ror16, 0xf)
GEN_VEXT_SHIFT_VV(vror_vv_w, uint32_t, uint32_t, H4, H4, ror32, 0x1f)
GEN_VEXT_SHIFT_VV(vror_vv_d, uint64_t, uint64_t, H8, H8, ror64, 0x3f)

> +GEN_VEXT_VV(vror_vv_b, 1)
> +GEN_VEXT_VV(vror_vv_h, 2)
> +GEN_VEXT_VV(vror_vv_w, 4)
> +GEN_VEXT_VV(vror_vv_d, 8)
> +
> +/*
> + * There's a missing tcg_gen_gvec_rotrs() helper function.
> + */
> +#define GEN_VEXT_VX_RTOL(NAME, ESZ)                                      \
> +void HELPER(NAME)(void *vd, void *v0, target_ulong s1, void *vs2,        \
> +                  CPURISCVState *env, uint32_t desc)                     \
> +{                                                                        \
> +    do_vext_vx(vd, v0, (ESZ << 3) - s1, vs2, env, desc, do_##NAME, ESZ); \
> +}
> +
> +/* DO_ROL because GEN_VEXT_VX_RTOL() converts from R to L */
> +RVVCALL(OPIVX2, vror_vx_b, OP_UUU_B, H1, H1, DO_ROL)
> +RVVCALL(OPIVX2, vror_vx_h, OP_UUU_H, H2, H2, DO_ROL)
> +RVVCALL(OPIVX2, vror_vx_w, OP_UUU_W, H4, H4, DO_ROL)
> +RVVCALL(OPIVX2, vror_vx_d, OP_UUU_D, H8, H8, DO_ROL)

Same applies as above:
/* vror.vx */
GEN_VEXT_SHIFT_VX(vror_vx_b, uint8_t,  uint8_t,  H1, H1, ror8,  0x7)
GEN_VEXT_SHIFT_VX(vror_vx_h, uint16_t, uint16_t, H2, H2, ror16, 0xf)
GEN_VEXT_SHIFT_VX(vror_vx_w, uint32_t, uint32_t, H4, H4, ror32, 0x1f)
GEN_VEXT_SHIFT_VX(vror_vx_d, uint64_t, uint64_t, H8, H8, ror64, 0x3f)

> +GEN_VEXT_VX_RTOL(vror_vx_b, 1)
> +GEN_VEXT_VX_RTOL(vror_vx_h, 2)
> +GEN_VEXT_VX_RTOL(vror_vx_w, 4)
> +GEN_VEXT_VX_RTOL(vror_vx_d, 8)
> +
> +RVVCALL(OPIVV2, vrol_vv_b, OP_UUU_B, H1, H1, H1, DO_ROL)
> +RVVCALL(OPIVV2, vrol_vv_h, OP_UUU_H, H2, H2, H2, DO_ROL)
> +RVVCALL(OPIVV2, vrol_vv_w, OP_UUU_W, H4, H4, H4, DO_ROL)
> +RVVCALL(OPIVV2, vrol_vv_d, OP_UUU_D, H8, H8, H8, DO_ROL)
> +GEN_VEXT_VV(vrol_vv_b, 1)
> +GEN_VEXT_VV(vrol_vv_h, 2)
> +GEN_VEXT_VV(vrol_vv_w, 4)
> +GEN_VEXT_VV(vrol_vv_d, 8)
> +
> +RVVCALL(OPIVX2, vrol_vx_b, OP_UUU_B, H1, H1, DO_ROL)
> +RVVCALL(OPIVX2, vrol_vx_h, OP_UUU_H, H2, H2, DO_ROL)
> +RVVCALL(OPIVX2, vrol_vx_w, OP_UUU_W, H4, H4, DO_ROL)
> +RVVCALL(OPIVX2, vrol_vx_d, OP_UUU_D, H8, H8, DO_ROL)
> +GEN_VEXT_VX(vrol_vx_b, 1)
> +GEN_VEXT_VX(vrol_vx_h, 2)
> +GEN_VEXT_VX(vrol_vx_w, 4)
> +GEN_VEXT_VX(vrol_vx_d, 8)
> diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
> index ab470092f6..ff7b03cbe3 100644
> --- a/target/riscv/vector_helper.c
> +++ b/target/riscv/vector_helper.c
> @@ -76,26 +76,6 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, 
> target_ulong s1,
>      return vl;
>  }
>
> -/*
> - * Note that vector data is stored in host-endian 64-bit chunks,
> - * so addressing units smaller than that needs a host-endian fixup.
> - */
> -#if HOST_BIG_ENDIAN
> -#define H1(x)   ((x) ^ 7)
> -#define H1_2(x) ((x) ^ 6)
> -#define H1_4(x) ((x) ^ 4)
> -#define H2(x)   ((x) ^ 3)
> -#define H4(x)   ((x) ^ 1)
> -#define H8(x)   ((x))
> -#else
> -#define H1(x)   (x)
> -#define H1_2(x) (x)
> -#define H1_4(x) (x)
> -#define H2(x)   (x)
> -#define H4(x)   (x)
> -#define H8(x)   (x)
> -#endif
> -
>  /*
>   * Get the maximum number of elements can be operated.
>   *
> @@ -683,18 +663,11 @@ GEN_VEXT_ST_WHOLE(vs8r_v, int8_t, ste_b)
>   *** Vector Integer Arithmetic Instructions
>   */
>
> -/* expand macro args before macro */
> -#define RVVCALL(macro, ...)  macro(__VA_ARGS__)
> -
>  /* (TD, T1, T2, TX1, TX2) */
>  #define OP_SSS_B int8_t, int8_t, int8_t, int8_t, int8_t
>  #define OP_SSS_H int16_t, int16_t, int16_t, int16_t, int16_t
>  #define OP_SSS_W int32_t, int32_t, int32_t, int32_t, int32_t
>  #define OP_SSS_D int64_t, int64_t, int64_t, int64_t, int64_t
> -#define OP_UUU_B uint8_t, uint8_t, uint8_t, uint8_t, uint8_t
> -#define OP_UUU_H uint16_t, uint16_t, uint16_t, uint16_t, uint16_t
> -#define OP_UUU_W uint32_t, uint32_t, uint32_t, uint32_t, uint32_t
> -#define OP_UUU_D uint64_t, uint64_t, uint64_t, uint64_t, uint64_t
>  #define OP_SUS_B int8_t, uint8_t, int8_t, uint8_t, int8_t
>  #define OP_SUS_H int16_t, uint16_t, int16_t, uint16_t, int16_t
>  #define OP_SUS_W int32_t, uint32_t, int32_t, uint32_t, int32_t
> @@ -718,14 +691,6 @@ GEN_VEXT_ST_WHOLE(vs8r_v, int8_t, ste_b)
>  #define NOP_UUU_H uint16_t, uint16_t, uint32_t, uint16_t, uint32_t
>  #define NOP_UUU_W uint32_t, uint32_t, uint64_t, uint32_t, uint64_t
>
> -
> -#define OPIVV2(NAME, TD, T1, T2, TX1, TX2, HD, HS1, HS2, OP)    \
> -static void do_##NAME(void *vd, void *vs1, void *vs2, int i)    \
> -{                                                               \
> -    TX1 s1 = *((T1 *)vs1 + HS1(i));                             \
> -    TX2 s2 = *((T2 *)vs2 + HS2(i));                             \
> -    *((TD *)vd + HD(i)) = OP(s2, s1);                           \
> -}
>  #define DO_SUB(N, M) (N - M)
>  #define DO_RSUB(N, M) (M - N)
>
> @@ -747,16 +712,6 @@ GEN_VEXT_VV(vsub_vv_h, 2)
>  GEN_VEXT_VV(vsub_vv_w, 4)
>  GEN_VEXT_VV(vsub_vv_d, 8)
>
> -/*
> - * (T1)s1 gives the real operator type.
> - * (TX1)(T1)s1 expands the operator type of widen or narrow operations.
> - */
> -#define OPIVX2(NAME, TD, T1, T2, TX1, TX2, HD, HS2, OP)             \
> -static void do_##NAME(void *vd, target_long s1, void *vs2, int i)   \
> -{                                                                   \
> -    TX2 s2 = *((T2 *)vs2 + HS2(i));                                 \
> -    *((TD *)vd + HD(i)) = OP(s2, (TX1)(T1)s1);                      \
> -}
>
>  RVVCALL(OPIVX2, vadd_vx_b, OP_SSS_B, H1, H1, DO_ADD)
>  RVVCALL(OPIVX2, vadd_vx_h, OP_SSS_H, H2, H2, DO_ADD)
> diff --git a/target/riscv/vector_internals.h b/target/riscv/vector_internals.h
> index 49529d2379..a0fbac7bf3 100644
> --- a/target/riscv/vector_internals.h
> +++ b/target/riscv/vector_internals.h
> @@ -28,6 +28,26 @@ static inline uint32_t vext_nf(uint32_t desc)
>      return FIELD_EX32(simd_data(desc), VDATA, NF);
>  }
>
> +/*
> + * Note that vector data is stored in host-endian 64-bit chunks,
> + * so addressing units smaller than that needs a host-endian fixup.
> + */
> +#if HOST_BIG_ENDIAN
> +#define H1(x)   ((x) ^ 7)
> +#define H1_2(x) ((x) ^ 6)
> +#define H1_4(x) ((x) ^ 4)
> +#define H2(x)   ((x) ^ 3)
> +#define H4(x)   ((x) ^ 1)
> +#define H8(x)   ((x))
> +#else
> +#define H1(x)   (x)
> +#define H1_2(x) (x)
> +#define H1_4(x) (x)
> +#define H2(x)   (x)
> +#define H4(x)   (x)
> +#define H8(x)   (x)
> +#endif
> +
>  /*
>   * Encode LMUL to lmul as following:
>   *     LMUL    vlmul    lmul
> @@ -96,9 +116,30 @@ static inline uint32_t vext_get_total_elems(CPURISCVState 
> *env, uint32_t desc,
>  void vext_set_elems_1s(void *base, uint32_t is_agnostic, uint32_t cnt,
>                         uint32_t tot);
>
> +/*
> + *** Vector Integer Arithmetic Instructions
> + */
> +
> +/* expand macro args before macro */
> +#define RVVCALL(macro, ...)  macro(__VA_ARGS__)
> +
> +/* (TD, T1, T2, TX1, TX2) */
> +#define OP_UUU_B uint8_t, uint8_t, uint8_t, uint8_t, uint8_t
> +#define OP_UUU_H uint16_t, uint16_t, uint16_t, uint16_t, uint16_t
> +#define OP_UUU_W uint32_t, uint32_t, uint32_t, uint32_t, uint32_t
> +#define OP_UUU_D uint64_t, uint64_t, uint64_t, uint64_t, uint64_t
> +
>  /* operation of two vector elements */
>  typedef void opivv2_fn(void *vd, void *vs1, void *vs2, int i);
>
> +#define OPIVV2(NAME, TD, T1, T2, TX1, TX2, HD, HS1, HS2, OP)    \
> +static void do_##NAME(void *vd, void *vs1, void *vs2, int i)    \
> +{                                                               \
> +    TX1 s1 = *((T1 *)vs1 + HS1(i));                             \
> +    TX2 s2 = *((T2 *)vs2 + HS2(i));                             \
> +    *((TD *)vd + HD(i)) = OP(s2, s1);                           \
> +}
> +
>  void do_vext_vv(void *vd, void *v0, void *vs1, void *vs2,
>                  CPURISCVState *env, uint32_t desc,
>                  opivv2_fn *fn, uint32_t esz);
> @@ -115,6 +156,17 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1,         
>  \
>
>  typedef void opivx2_fn(void *vd, target_long s1, void *vs2, int i);
>
> +/*
> + * (T1)s1 gives the real operator type.
> + * (TX1)(T1)s1 expands the operator type of widen or narrow operations.
> + */
> +#define OPIVX2(NAME, TD, T1, T2, TX1, TX2, HD, HS2, OP)             \
> +static void do_##NAME(void *vd, target_long s1, void *vs2, int i)   \
> +{                                                                   \
> +    TX2 s2 = *((T2 *)vs2 + HS2(i));                                 \
> +    *((TD *)vd + HD(i)) = OP(s2, (TX1)(T1)s1);                      \
> +}
> +
>  void do_vext_vx(void *vd, void *v0, target_long s1, void *vs2,
>                  CPURISCVState *env, uint32_t desc,
>                  opivx2_fn fn, uint32_t esz);

Again: refactoring needs to go into a separate patch.

> --
> 2.39.1
>