Re: [Qemu-devel] [Qemu-riscv] [PATCH v2 04/17] RISC-V: add vector extension configure instruction

[Chih-Min Chao <chihmin.chao@sifive.com>]

On Wed, Sep 11, 2019 at 2:38 PM liuzhiwei <zhiwei_liu@c-sky.com> wrote:

> From: LIU Zhiwei <zhiwei_liu@c-sky.com>
>
> Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
> ---
>  target/riscv/Makefile.objs              |   2 +-
>  target/riscv/helper.h                   |   3 +
>  target/riscv/insn32.decode              |   5 ++
>  target/riscv/insn_trans/trans_rvv.inc.c |  46 ++++++++++++
>  target/riscv/translate.c                |   1 +
>  target/riscv/vector_helper.c            | 126
> ++++++++++++++++++++++++++++++++
>  6 files changed, 182 insertions(+), 1 deletion(-)
>  create mode 100644 target/riscv/insn_trans/trans_rvv.inc.c
>  create mode 100644 target/riscv/vector_helper.c
>
> diff --git a/target/riscv/Makefile.objs b/target/riscv/Makefile.objs
> index b1c79bc..d577cef 100644
> --- a/target/riscv/Makefile.objs
> +++ b/target/riscv/Makefile.objs
> @@ -1,4 +1,4 @@
> -obj-y += translate.o op_helper.o cpu_helper.o cpu.o csr.o fpu_helper.o
> gdbstub.o pmp.o
> +obj-y += translate.o op_helper.o cpu_helper.o cpu.o csr.o fpu_helper.o
> vector_helper.o gdbstub.o pmp.o
>
>  DECODETREE = $(SRC_PATH)/scripts/decodetree.py
>
> diff --git a/target/riscv/helper.h b/target/riscv/helper.h
> index debb22a..652f8c3 100644
> --- a/target/riscv/helper.h
> +++ b/target/riscv/helper.h
> @@ -76,3 +76,6 @@ DEF_HELPER_2(mret, tl, env, tl)
>  DEF_HELPER_1(wfi, void, env)
>  DEF_HELPER_1(tlb_flush, void, env)
>  #endif
> +/* Vector functions */
> +DEF_HELPER_4(vector_vsetvli, void, env, i32, i32, i32)
> +DEF_HELPER_4(vector_vsetvl, void, env, i32, i32, i32)
> diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
> index 77f794e..5dc009c 100644
> --- a/target/riscv/insn32.decode
> +++ b/target/riscv/insn32.decode
> @@ -62,6 +62,7 @@
>  @r_rm    .......   ..... ..... ... ..... ....... %rs2 %rs1 %rm %rd
>  @r2_rm   .......   ..... ..... ... ..... ....... %rs1 %rm %rd
>  @r2      .......   ..... ..... ... ..... ....... %rs1 %rd
> +@r2_zimm . zimm:11  ..... ... ..... ....... %rs1 %rd
>
>  @sfence_vma ....... ..... .....   ... ..... ....... %rs2 %rs1
>  @sfence_vm  ....... ..... .....   ... ..... ....... %rs1
> @@ -203,3 +204,7 @@ fcvt_w_d   1100001  00000 ..... ... ..... 1010011
> @r2_rm
>  fcvt_wu_d  1100001  00001 ..... ... ..... 1010011 @r2_rm
>  fcvt_d_w   1101001  00000 ..... ... ..... 1010011 @r2_rm
>  fcvt_d_wu  1101001  00001 ..... ... ..... 1010011 @r2_rm
> +
> +# *** RV32V Extension ***
> +vsetvli         0 ........... ..... 111 ..... 1010111  @r2_zimm
> +vsetvl          1000000 ..... ..... 111 ..... 1010111  @r
> diff --git a/target/riscv/insn_trans/trans_rvv.inc.c
> b/target/riscv/insn_trans/trans_rvv.inc.c
> new file mode 100644
> index 0000000..82e7ad6
> --- /dev/null
> +++ b/target/riscv/insn_trans/trans_rvv.inc.c
> @@ -0,0 +1,46 @@
> +/*
> + * RISC-V translation routines for the RVV Standard Extension.
> + *
> + * Copyright (c) 2019 C-SKY Limited. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2 or later, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
> for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License
> along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#define GEN_VECTOR_R(INSN) \
> +static bool trans_##INSN(DisasContext *ctx, arg_##INSN * a) \
> +{                                                      \
> +    TCGv_i32 s1 = tcg_const_i32(a->rs1);               \
> +    TCGv_i32 s2 = tcg_const_i32(a->rs2);               \
> +    TCGv_i32 d  = tcg_const_i32(a->rd);                \
> +    gen_helper_vector_##INSN(cpu_env, s1, s2, d);    \
> +    tcg_temp_free_i32(s1);                             \
> +    tcg_temp_free_i32(s2);                             \
> +    tcg_temp_free_i32(d);                              \
> +    return true;                                       \
> +}
> +
> +#define GEN_VECTOR_R2_ZIMM(INSN) \
> +static bool trans_##INSN(DisasContext *ctx, arg_##INSN * a) \
> +{                                                      \
> +    TCGv_i32 s1 = tcg_const_i32(a->rs1);               \
> +    TCGv_i32 zimm = tcg_const_i32(a->zimm);            \
> +    TCGv_i32 d  = tcg_const_i32(a->rd);                \
> +    gen_helper_vector_##INSN(cpu_env, s1, zimm, d);      \
> +    tcg_temp_free_i32(s1);                             \
> +    tcg_temp_free_i32(zimm);                           \
> +    tcg_temp_free_i32(d);                              \
> +    return true;                                       \
> +}
> +
> +GEN_VECTOR_R2_ZIMM(vsetvli)
> +GEN_VECTOR_R(vsetvl)
> diff --git a/target/riscv/translate.c b/target/riscv/translate.c
> index 8d6ab73..587c23e 100644
> --- a/target/riscv/translate.c
> +++ b/target/riscv/translate.c
> @@ -706,6 +706,7 @@ static bool gen_shift(DisasContext *ctx, arg_r *a,
>  #include "insn_trans/trans_rva.inc.c"
>  #include "insn_trans/trans_rvf.inc.c"
>  #include "insn_trans/trans_rvd.inc.c"
> +#include "insn_trans/trans_rvv.inc.c"
>  #include "insn_trans/trans_privileged.inc.c"
>
>  /*
> diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
> new file mode 100644
> index 0000000..b279e6f
> --- /dev/null
> +++ b/target/riscv/vector_helper.c
> @@ -0,0 +1,126 @@
> +/*
> + * RISC-V Vectore Extension Helpers for QEMU.
> + *
> + * Copyright (c) 2019 C-SKY Limited. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2 or later, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
> for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License
> along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "cpu.h"
> +#include "exec/exec-all.h"
> +#include "exec/helper-proto.h"
> +#include <math.h>
> +
> +#define VECTOR_HELPER(name) HELPER(glue(vector_, name))
> +
> +static inline void vector_vtype_set_ill(CPURISCVState *env)
> +{
> +    env->vfp.vtype = ((target_ulong)1) << (sizeof(target_ulong) - 1);
> +    return;
> +}
> +
>
   env->vfp.vtype = ((target_ulong)1) << (sizeof(target_ulong) * 8 - 1);

> +static inline int vector_vtype_get_sew(CPURISCVState *env)
> +{
> +    return (env->vfp.vtype >> 2) & 0x7;
> +}
> +
>
 extract64(env->vfp.vtype, 2, 3);

> +static inline int vector_get_width(CPURISCVState *env)
> +{
> +    return  8 * (1 << vector_vtype_get_sew(env));
> +}
> +
> +static inline int vector_get_lmul(CPURISCVState *env)
> +{
> +    return 1 << (env->vfp.vtype & 0x3);
> +}
> +
>
 extract64(env->vfp.vtype, 0, 2);

> +static inline int vector_get_vlmax(CPURISCVState *env)
> +{
> +    return vector_get_lmul(env) * VLEN / vector_get_width(env);
> +}
> +
> +void VECTOR_HELPER(vsetvl)(CPURISCVState *env, uint32_t rs1, uint32_t rs2,
> +    uint32_t rd)
> +{
> +    int sew, max_sew, vlmax, vl;
> +
> +    if (rs2 == 0) {
> +        vector_vtype_set_ill(env);
> +        riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
> +        return;
> +    }
> +    env->vfp.vtype = env->gpr[rs2];
> +    sew = 1 << vector_get_width(env) / 8;
> +    max_sew = sizeof(target_ulong);
> +
> +    if (env->misa & RVD) {
> +        max_sew = max_sew > 8 ? max_sew : 8;
> +    } else if (env->misa & RVF) {
> +        max_sew = max_sew > 4 ? max_sew : 4;
> +    }


As far as i understand, max_sew is defined by ELEN but not by existing
floating-point extensions.
ELEN should be configurable through command line cpu parameter.



+    if (sew > max_sew) {
> +        vector_vtype_set_ill(env);
> +        return;
> +    }
> +
> +    vlmax = vector_get_vlmax(env);
> +    if (rs1 == 0) {
> +        vl = vlmax;
> +    } else if (env->gpr[rs1] <= vlmax) {
> +        vl = env->gpr[rs1];
> +    } else if (env->gpr[rs1] < 2 * vlmax) {
> +        vl = ceil(env->gpr[rs1] / 2);
> +    } else {
> +        vl = vlmax;
> +    }
> +    env->vfp.vl = vl;
> +    env->gpr[rd] = vl;
> +    env->vfp.vstart = 0;
> +    return;
> +}
> +
> +void VECTOR_HELPER(vsetvli)(CPURISCVState *env, uint32_t rs1, uint32_t
> zimm,
> +    uint32_t rd)
> +{
> +    int sew, max_sew, vlmax, vl;
> +
> +    env->vfp.vtype = zimm;
> +    sew = vector_get_width(env) / 8;
> +    max_sew = sizeof(target_ulong);
> +
> +    if (env->misa & RVD) {
> +        max_sew = max_sew > 8 ? max_sew : 8;
> +    } else if (env->misa & RVF) {
> +        max_sew = max_sew > 4 ? max_sew : 4;
> +    }
> +    if (sew > max_sew) {
> +        vector_vtype_set_ill(env);
> +        return;
> +    }
> +

The same comment described above.

> +    vlmax = vector_get_vlmax(env);
> +    if (rs1 == 0) {
> +        vl = vlmax;
> +    } else if (env->gpr[rs1] <= vlmax) {
> +        vl = env->gpr[rs1];
> +    } else if (env->gpr[rs1] < 2 * vlmax) {
> +        vl = ceil(env->gpr[rs1] / 2);
> +    } else {
> +        vl = vlmax;
> +    }
> +    env->vfp.vl = vl;
> +    env->gpr[rd] = vl;
> +    env->vfp.vstart = 0;
> +    return;
> +}
> --
> 2.7.4
>
>
>