xemu/target/riscv/insn_trans/trans_rvv.inc.c

/*
 * RISC-V translation routines for the RVV Standard Extension.
 *
 * Copyright (c) 2020 T-Head Semiconductor Co., Ltd. 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 "tcg/tcg-op-gvec.h"
#include "tcg/tcg-gvec-desc.h"
#include "internals.h"

static bool trans_vsetvl(DisasContext *ctx, arg_vsetvl *a)
{
    TCGv s1, s2, dst;

    if (!has_ext(ctx, RVV)) {
        return false;
    }

    s2 = tcg_temp_new();
    dst = tcg_temp_new();

    /* Using x0 as the rs1 register specifier, encodes an infinite AVL */
    if (a->rs1 == 0) {
        /* As the mask is at least one bit, RV_VLEN_MAX is >= VLMAX */
        s1 = tcg_const_tl(RV_VLEN_MAX);
    } else {
        s1 = tcg_temp_new();
        gen_get_gpr(s1, a->rs1);
    }
    gen_get_gpr(s2, a->rs2);
    gen_helper_vsetvl(dst, cpu_env, s1, s2);
    gen_set_gpr(a->rd, dst);
    tcg_gen_movi_tl(cpu_pc, ctx->pc_succ_insn);
    lookup_and_goto_ptr(ctx);
    ctx->base.is_jmp = DISAS_NORETURN;

    tcg_temp_free(s1);
    tcg_temp_free(s2);
    tcg_temp_free(dst);
    return true;
}

static bool trans_vsetvli(DisasContext *ctx, arg_vsetvli *a)
{
    TCGv s1, s2, dst;

    if (!has_ext(ctx, RVV)) {
        return false;
    }

    s2 = tcg_const_tl(a->zimm);
    dst = tcg_temp_new();

    /* Using x0 as the rs1 register specifier, encodes an infinite AVL */
    if (a->rs1 == 0) {
        /* As the mask is at least one bit, RV_VLEN_MAX is >= VLMAX */
        s1 = tcg_const_tl(RV_VLEN_MAX);
    } else {
        s1 = tcg_temp_new();
        gen_get_gpr(s1, a->rs1);
    }
    gen_helper_vsetvl(dst, cpu_env, s1, s2);
    gen_set_gpr(a->rd, dst);
    gen_goto_tb(ctx, 0, ctx->pc_succ_insn);
    ctx->base.is_jmp = DISAS_NORETURN;

    tcg_temp_free(s1);
    tcg_temp_free(s2);
    tcg_temp_free(dst);
    return true;
}

/* vector register offset from env */
static uint32_t vreg_ofs(DisasContext *s, int reg)
{
    return offsetof(CPURISCVState, vreg) + reg * s->vlen / 8;
}

/* check functions */

/*
 * In cpu_get_tb_cpu_state(), set VILL if RVV was not present.
 * So RVV is also be checked in this function.
 */
static bool vext_check_isa_ill(DisasContext *s)
{
    return !s->vill;
}

/*
 * There are two rules check here.
 *
 * 1. Vector register numbers are multiples of LMUL. (Section 3.2)
 *
 * 2. For all widening instructions, the destination LMUL value must also be
 *    a supported LMUL value. (Section 11.2)
 */
static bool vext_check_reg(DisasContext *s, uint32_t reg, bool widen)
{
    /*
     * The destination vector register group results are arranged as if both
     * SEW and LMUL were at twice their current settings. (Section 11.2).
     */
    int legal = widen ? 2 << s->lmul : 1 << s->lmul;

    return !((s->lmul == 0x3 && widen) || (reg % legal));
}

/*
 * There are two rules check here.
 *
 * 1. The destination vector register group for a masked vector instruction can
 *    only overlap the source mask register (v0) when LMUL=1. (Section 5.3)
 *
 * 2. In widen instructions and some other insturctions, like vslideup.vx,
 *    there is no need to check whether LMUL=1.
 */
static bool vext_check_overlap_mask(DisasContext *s, uint32_t vd, bool vm,
    bool force)
{
    return (vm != 0 || vd != 0) || (!force && (s->lmul == 0));
}

/* The LMUL setting must be such that LMUL * NFIELDS <= 8. (Section 7.8) */
static bool vext_check_nf(DisasContext *s, uint32_t nf)
{
    return (1 << s->lmul) * nf <= 8;
}

/* common translation macro */
#define GEN_VEXT_TRANS(NAME, SEQ, ARGTYPE, OP, CHECK)      \
static bool trans_##NAME(DisasContext *s, arg_##ARGTYPE *a)\
{                                                          \
    if (CHECK(s, a)) {                                     \
        return OP(s, a, SEQ);                              \
    }                                                      \
    return false;                                          \
}

/*
 *** unit stride load and store
 */
typedef void gen_helper_ldst_us(TCGv_ptr, TCGv_ptr, TCGv,
                                TCGv_env, TCGv_i32);

static bool ldst_us_trans(uint32_t vd, uint32_t rs1, uint32_t data,
                          gen_helper_ldst_us *fn, DisasContext *s)
{
    TCGv_ptr dest, mask;
    TCGv base;
    TCGv_i32 desc;

    TCGLabel *over = gen_new_label();
    tcg_gen_brcondi_tl(TCG_COND_EQ, cpu_vl, 0, over);

    dest = tcg_temp_new_ptr();
    mask = tcg_temp_new_ptr();
    base = tcg_temp_new();

    /*
     * As simd_desc supports at most 256 bytes, and in this implementation,
     * the max vector group length is 2048 bytes. So split it into two parts.
     *
     * The first part is vlen in bytes, encoded in maxsz of simd_desc.
     * The second part is lmul, encoded in data of simd_desc.
     */
    desc = tcg_const_i32(simd_desc(0, s->vlen / 8, data));

    gen_get_gpr(base, rs1);
    tcg_gen_addi_ptr(dest, cpu_env, vreg_ofs(s, vd));
    tcg_gen_addi_ptr(mask, cpu_env, vreg_ofs(s, 0));

    fn(dest, mask, base, cpu_env, desc);

    tcg_temp_free_ptr(dest);
    tcg_temp_free_ptr(mask);
    tcg_temp_free(base);
    tcg_temp_free_i32(desc);
    gen_set_label(over);
    return true;
}

static bool ld_us_op(DisasContext *s, arg_r2nfvm *a, uint8_t seq)
{
    uint32_t data = 0;
    gen_helper_ldst_us *fn;
    static gen_helper_ldst_us * const fns[2][7][4] = {
        /* masked unit stride load */
        { { gen_helper_vlb_v_b_mask,  gen_helper_vlb_v_h_mask,
            gen_helper_vlb_v_w_mask,  gen_helper_vlb_v_d_mask },
          { NULL,                     gen_helper_vlh_v_h_mask,
            gen_helper_vlh_v_w_mask,  gen_helper_vlh_v_d_mask },
          { NULL,                     NULL,
            gen_helper_vlw_v_w_mask,  gen_helper_vlw_v_d_mask },
          { gen_helper_vle_v_b_mask,  gen_helper_vle_v_h_mask,
            gen_helper_vle_v_w_mask,  gen_helper_vle_v_d_mask },
          { gen_helper_vlbu_v_b_mask, gen_helper_vlbu_v_h_mask,
            gen_helper_vlbu_v_w_mask, gen_helper_vlbu_v_d_mask },
          { NULL,                     gen_helper_vlhu_v_h_mask,
            gen_helper_vlhu_v_w_mask, gen_helper_vlhu_v_d_mask },
          { NULL,                     NULL,
            gen_helper_vlwu_v_w_mask, gen_helper_vlwu_v_d_mask } },
        /* unmasked unit stride load */
        { { gen_helper_vlb_v_b,  gen_helper_vlb_v_h,
            gen_helper_vlb_v_w,  gen_helper_vlb_v_d },
          { NULL,                gen_helper_vlh_v_h,
            gen_helper_vlh_v_w,  gen_helper_vlh_v_d },
          { NULL,                NULL,
            gen_helper_vlw_v_w,  gen_helper_vlw_v_d },
          { gen_helper_vle_v_b,  gen_helper_vle_v_h,
            gen_helper_vle_v_w,  gen_helper_vle_v_d },
          { gen_helper_vlbu_v_b, gen_helper_vlbu_v_h,
            gen_helper_vlbu_v_w, gen_helper_vlbu_v_d },
          { NULL,                gen_helper_vlhu_v_h,
            gen_helper_vlhu_v_w, gen_helper_vlhu_v_d },
          { NULL,                NULL,
            gen_helper_vlwu_v_w, gen_helper_vlwu_v_d } }
    };

    fn =  fns[a->vm][seq][s->sew];
    if (fn == NULL) {
        return false;
    }

    data = FIELD_DP32(data, VDATA, MLEN, s->mlen);
    data = FIELD_DP32(data, VDATA, VM, a->vm);
    data = FIELD_DP32(data, VDATA, LMUL, s->lmul);
    data = FIELD_DP32(data, VDATA, NF, a->nf);
    return ldst_us_trans(a->rd, a->rs1, data, fn, s);
}

static bool ld_us_check(DisasContext *s, arg_r2nfvm* a)
{
    return (vext_check_isa_ill(s) &&
            vext_check_overlap_mask(s, a->rd, a->vm, false) &&
            vext_check_reg(s, a->rd, false) &&
            vext_check_nf(s, a->nf));
}

GEN_VEXT_TRANS(vlb_v, 0, r2nfvm, ld_us_op, ld_us_check)
GEN_VEXT_TRANS(vlh_v, 1, r2nfvm, ld_us_op, ld_us_check)
GEN_VEXT_TRANS(vlw_v, 2, r2nfvm, ld_us_op, ld_us_check)
GEN_VEXT_TRANS(vle_v, 3, r2nfvm, ld_us_op, ld_us_check)
GEN_VEXT_TRANS(vlbu_v, 4, r2nfvm, ld_us_op, ld_us_check)
GEN_VEXT_TRANS(vlhu_v, 5, r2nfvm, ld_us_op, ld_us_check)
GEN_VEXT_TRANS(vlwu_v, 6, r2nfvm, ld_us_op, ld_us_check)

static bool st_us_op(DisasContext *s, arg_r2nfvm *a, uint8_t seq)
{
    uint32_t data = 0;
    gen_helper_ldst_us *fn;
    static gen_helper_ldst_us * const fns[2][4][4] = {
        /* masked unit stride load and store */
        { { gen_helper_vsb_v_b_mask,  gen_helper_vsb_v_h_mask,
            gen_helper_vsb_v_w_mask,  gen_helper_vsb_v_d_mask },
          { NULL,                     gen_helper_vsh_v_h_mask,
            gen_helper_vsh_v_w_mask,  gen_helper_vsh_v_d_mask },
          { NULL,                     NULL,
            gen_helper_vsw_v_w_mask,  gen_helper_vsw_v_d_mask },
          { gen_helper_vse_v_b_mask,  gen_helper_vse_v_h_mask,
            gen_helper_vse_v_w_mask,  gen_helper_vse_v_d_mask } },
        /* unmasked unit stride store */
        { { gen_helper_vsb_v_b,  gen_helper_vsb_v_h,
            gen_helper_vsb_v_w,  gen_helper_vsb_v_d },
          { NULL,                gen_helper_vsh_v_h,
            gen_helper_vsh_v_w,  gen_helper_vsh_v_d },
          { NULL,                NULL,
            gen_helper_vsw_v_w,  gen_helper_vsw_v_d },
          { gen_helper_vse_v_b,  gen_helper_vse_v_h,
            gen_helper_vse_v_w,  gen_helper_vse_v_d } }
    };

    fn =  fns[a->vm][seq][s->sew];
    if (fn == NULL) {
        return false;
    }

    data = FIELD_DP32(data, VDATA, MLEN, s->mlen);
    data = FIELD_DP32(data, VDATA, VM, a->vm);
    data = FIELD_DP32(data, VDATA, LMUL, s->lmul);
    data = FIELD_DP32(data, VDATA, NF, a->nf);
    return ldst_us_trans(a->rd, a->rs1, data, fn, s);
}

static bool st_us_check(DisasContext *s, arg_r2nfvm* a)
{
    return (vext_check_isa_ill(s) &&
            vext_check_reg(s, a->rd, false) &&
            vext_check_nf(s, a->nf));
}

GEN_VEXT_TRANS(vsb_v, 0, r2nfvm, st_us_op, st_us_check)
GEN_VEXT_TRANS(vsh_v, 1, r2nfvm, st_us_op, st_us_check)
GEN_VEXT_TRANS(vsw_v, 2, r2nfvm, st_us_op, st_us_check)
GEN_VEXT_TRANS(vse_v, 3, r2nfvm, st_us_op, st_us_check)

/*
 *** stride load and store
 */
typedef void gen_helper_ldst_stride(TCGv_ptr, TCGv_ptr, TCGv,
                                    TCGv, TCGv_env, TCGv_i32);

static bool ldst_stride_trans(uint32_t vd, uint32_t rs1, uint32_t rs2,
                              uint32_t data, gen_helper_ldst_stride *fn,
                              DisasContext *s)
{
    TCGv_ptr dest, mask;
    TCGv base, stride;
    TCGv_i32 desc;

    TCGLabel *over = gen_new_label();
    tcg_gen_brcondi_tl(TCG_COND_EQ, cpu_vl, 0, over);

    dest = tcg_temp_new_ptr();
    mask = tcg_temp_new_ptr();
    base = tcg_temp_new();
    stride = tcg_temp_new();
    desc = tcg_const_i32(simd_desc(0, s->vlen / 8, data));

    gen_get_gpr(base, rs1);
    gen_get_gpr(stride, rs2);
    tcg_gen_addi_ptr(dest, cpu_env, vreg_ofs(s, vd));
    tcg_gen_addi_ptr(mask, cpu_env, vreg_ofs(s, 0));

    fn(dest, mask, base, stride, cpu_env, desc);

    tcg_temp_free_ptr(dest);
    tcg_temp_free_ptr(mask);
    tcg_temp_free(base);
    tcg_temp_free(stride);
    tcg_temp_free_i32(desc);
    gen_set_label(over);
    return true;
}

static bool ld_stride_op(DisasContext *s, arg_rnfvm *a, uint8_t seq)
{
    uint32_t data = 0;
    gen_helper_ldst_stride *fn;
    static gen_helper_ldst_stride * const fns[7][4] = {
        { gen_helper_vlsb_v_b,  gen_helper_vlsb_v_h,
          gen_helper_vlsb_v_w,  gen_helper_vlsb_v_d },
        { NULL,                 gen_helper_vlsh_v_h,
          gen_helper_vlsh_v_w,  gen_helper_vlsh_v_d },
        { NULL,                 NULL,
          gen_helper_vlsw_v_w,  gen_helper_vlsw_v_d },
        { gen_helper_vlse_v_b,  gen_helper_vlse_v_h,
          gen_helper_vlse_v_w,  gen_helper_vlse_v_d },
        { gen_helper_vlsbu_v_b, gen_helper_vlsbu_v_h,
          gen_helper_vlsbu_v_w, gen_helper_vlsbu_v_d },
        { NULL,                 gen_helper_vlshu_v_h,
          gen_helper_vlshu_v_w, gen_helper_vlshu_v_d },
        { NULL,                 NULL,
          gen_helper_vlswu_v_w, gen_helper_vlswu_v_d },
    };

    fn =  fns[seq][s->sew];
    if (fn == NULL) {
        return false;
    }

    data = FIELD_DP32(data, VDATA, MLEN, s->mlen);
    data = FIELD_DP32(data, VDATA, VM, a->vm);
    data = FIELD_DP32(data, VDATA, LMUL, s->lmul);
    data = FIELD_DP32(data, VDATA, NF, a->nf);
    return ldst_stride_trans(a->rd, a->rs1, a->rs2, data, fn, s);
}

static bool ld_stride_check(DisasContext *s, arg_rnfvm* a)
{
    return (vext_check_isa_ill(s) &&
            vext_check_overlap_mask(s, a->rd, a->vm, false) &&
            vext_check_reg(s, a->rd, false) &&
            vext_check_nf(s, a->nf));
}

GEN_VEXT_TRANS(vlsb_v, 0, rnfvm, ld_stride_op, ld_stride_check)
GEN_VEXT_TRANS(vlsh_v, 1, rnfvm, ld_stride_op, ld_stride_check)
GEN_VEXT_TRANS(vlsw_v, 2, rnfvm, ld_stride_op, ld_stride_check)
GEN_VEXT_TRANS(vlse_v, 3, rnfvm, ld_stride_op, ld_stride_check)
GEN_VEXT_TRANS(vlsbu_v, 4, rnfvm, ld_stride_op, ld_stride_check)
GEN_VEXT_TRANS(vlshu_v, 5, rnfvm, ld_stride_op, ld_stride_check)
GEN_VEXT_TRANS(vlswu_v, 6, rnfvm, ld_stride_op, ld_stride_check)

static bool st_stride_op(DisasContext *s, arg_rnfvm *a, uint8_t seq)
{
    uint32_t data = 0;
    gen_helper_ldst_stride *fn;
    static gen_helper_ldst_stride * const fns[4][4] = {
        /* masked stride store */
        { gen_helper_vssb_v_b,  gen_helper_vssb_v_h,
          gen_helper_vssb_v_w,  gen_helper_vssb_v_d },
        { NULL,                 gen_helper_vssh_v_h,
          gen_helper_vssh_v_w,  gen_helper_vssh_v_d },
        { NULL,                 NULL,
          gen_helper_vssw_v_w,  gen_helper_vssw_v_d },
        { gen_helper_vsse_v_b,  gen_helper_vsse_v_h,
          gen_helper_vsse_v_w,  gen_helper_vsse_v_d }
    };

    data = FIELD_DP32(data, VDATA, MLEN, s->mlen);
    data = FIELD_DP32(data, VDATA, VM, a->vm);
    data = FIELD_DP32(data, VDATA, LMUL, s->lmul);
    data = FIELD_DP32(data, VDATA, NF, a->nf);
    fn =  fns[seq][s->sew];
    if (fn == NULL) {
        return false;
    }

    return ldst_stride_trans(a->rd, a->rs1, a->rs2, data, fn, s);
}

static bool st_stride_check(DisasContext *s, arg_rnfvm* a)
{
    return (vext_check_isa_ill(s) &&
            vext_check_reg(s, a->rd, false) &&
            vext_check_nf(s, a->nf));
}

GEN_VEXT_TRANS(vssb_v, 0, rnfvm, st_stride_op, st_stride_check)
GEN_VEXT_TRANS(vssh_v, 1, rnfvm, st_stride_op, st_stride_check)
GEN_VEXT_TRANS(vssw_v, 2, rnfvm, st_stride_op, st_stride_check)
GEN_VEXT_TRANS(vsse_v, 3, rnfvm, st_stride_op, st_stride_check)

/*
 *** index load and store
 */
typedef void gen_helper_ldst_index(TCGv_ptr, TCGv_ptr, TCGv,
                                   TCGv_ptr, TCGv_env, TCGv_i32);

static bool ldst_index_trans(uint32_t vd, uint32_t rs1, uint32_t vs2,
                             uint32_t data, gen_helper_ldst_index *fn,
                             DisasContext *s)
{
    TCGv_ptr dest, mask, index;
    TCGv base;
    TCGv_i32 desc;

    TCGLabel *over = gen_new_label();
    tcg_gen_brcondi_tl(TCG_COND_EQ, cpu_vl, 0, over);

    dest = tcg_temp_new_ptr();
    mask = tcg_temp_new_ptr();
    index = tcg_temp_new_ptr();
    base = tcg_temp_new();
    desc = tcg_const_i32(simd_desc(0, s->vlen / 8, data));

    gen_get_gpr(base, rs1);
    tcg_gen_addi_ptr(dest, cpu_env, vreg_ofs(s, vd));
    tcg_gen_addi_ptr(index, cpu_env, vreg_ofs(s, vs2));
    tcg_gen_addi_ptr(mask, cpu_env, vreg_ofs(s, 0));

    fn(dest, mask, base, index, cpu_env, desc);

    tcg_temp_free_ptr(dest);
    tcg_temp_free_ptr(mask);
    tcg_temp_free_ptr(index);
    tcg_temp_free(base);
    tcg_temp_free_i32(desc);
    gen_set_label(over);
    return true;
}

static bool ld_index_op(DisasContext *s, arg_rnfvm *a, uint8_t seq)
{
    uint32_t data = 0;
    gen_helper_ldst_index *fn;
    static gen_helper_ldst_index * const fns[7][4] = {
        { gen_helper_vlxb_v_b,  gen_helper_vlxb_v_h,
          gen_helper_vlxb_v_w,  gen_helper_vlxb_v_d },
        { NULL,                 gen_helper_vlxh_v_h,
          gen_helper_vlxh_v_w,  gen_helper_vlxh_v_d },
        { NULL,                 NULL,
          gen_helper_vlxw_v_w,  gen_helper_vlxw_v_d },
        { gen_helper_vlxe_v_b,  gen_helper_vlxe_v_h,
          gen_helper_vlxe_v_w,  gen_helper_vlxe_v_d },
        { gen_helper_vlxbu_v_b, gen_helper_vlxbu_v_h,
          gen_helper_vlxbu_v_w, gen_helper_vlxbu_v_d },
        { NULL,                 gen_helper_vlxhu_v_h,
          gen_helper_vlxhu_v_w, gen_helper_vlxhu_v_d },
        { NULL,                 NULL,
          gen_helper_vlxwu_v_w, gen_helper_vlxwu_v_d },
    };

    fn =  fns[seq][s->sew];
    if (fn == NULL) {
        return false;
    }

    data = FIELD_DP32(data, VDATA, MLEN, s->mlen);
    data = FIELD_DP32(data, VDATA, VM, a->vm);
    data = FIELD_DP32(data, VDATA, LMUL, s->lmul);
    data = FIELD_DP32(data, VDATA, NF, a->nf);
    return ldst_index_trans(a->rd, a->rs1, a->rs2, data, fn, s);
}

static bool ld_index_check(DisasContext *s, arg_rnfvm* a)
{
    return (vext_check_isa_ill(s) &&
            vext_check_overlap_mask(s, a->rd, a->vm, false) &&
            vext_check_reg(s, a->rd, false) &&
            vext_check_reg(s, a->rs2, false) &&
            vext_check_nf(s, a->nf));
}

GEN_VEXT_TRANS(vlxb_v, 0, rnfvm, ld_index_op, ld_index_check)
GEN_VEXT_TRANS(vlxh_v, 1, rnfvm, ld_index_op, ld_index_check)
GEN_VEXT_TRANS(vlxw_v, 2, rnfvm, ld_index_op, ld_index_check)
GEN_VEXT_TRANS(vlxe_v, 3, rnfvm, ld_index_op, ld_index_check)
GEN_VEXT_TRANS(vlxbu_v, 4, rnfvm, ld_index_op, ld_index_check)
GEN_VEXT_TRANS(vlxhu_v, 5, rnfvm, ld_index_op, ld_index_check)
GEN_VEXT_TRANS(vlxwu_v, 6, rnfvm, ld_index_op, ld_index_check)

static bool st_index_op(DisasContext *s, arg_rnfvm *a, uint8_t seq)
{
    uint32_t data = 0;
    gen_helper_ldst_index *fn;
    static gen_helper_ldst_index * const fns[4][4] = {
        { gen_helper_vsxb_v_b,  gen_helper_vsxb_v_h,
          gen_helper_vsxb_v_w,  gen_helper_vsxb_v_d },
        { NULL,                 gen_helper_vsxh_v_h,
          gen_helper_vsxh_v_w,  gen_helper_vsxh_v_d },
        { NULL,                 NULL,
          gen_helper_vsxw_v_w,  gen_helper_vsxw_v_d },
        { gen_helper_vsxe_v_b,  gen_helper_vsxe_v_h,
          gen_helper_vsxe_v_w,  gen_helper_vsxe_v_d }
    };

    fn =  fns[seq][s->sew];
    if (fn == NULL) {
        return false;
    }

    data = FIELD_DP32(data, VDATA, MLEN, s->mlen);
    data = FIELD_DP32(data, VDATA, VM, a->vm);
    data = FIELD_DP32(data, VDATA, LMUL, s->lmul);
    data = FIELD_DP32(data, VDATA, NF, a->nf);
    return ldst_index_trans(a->rd, a->rs1, a->rs2, data, fn, s);
}

static bool st_index_check(DisasContext *s, arg_rnfvm* a)
{
    return (vext_check_isa_ill(s) &&
            vext_check_reg(s, a->rd, false) &&
            vext_check_reg(s, a->rs2, false) &&
            vext_check_nf(s, a->nf));
}

GEN_VEXT_TRANS(vsxb_v, 0, rnfvm, st_index_op, st_index_check)
GEN_VEXT_TRANS(vsxh_v, 1, rnfvm, st_index_op, st_index_check)
GEN_VEXT_TRANS(vsxw_v, 2, rnfvm, st_index_op, st_index_check)
GEN_VEXT_TRANS(vsxe_v, 3, rnfvm, st_index_op, st_index_check)

/*
 *** unit stride fault-only-first load
 */
static bool ldff_trans(uint32_t vd, uint32_t rs1, uint32_t data,
                       gen_helper_ldst_us *fn, DisasContext *s)
{
    TCGv_ptr dest, mask;
    TCGv base;
    TCGv_i32 desc;

    TCGLabel *over = gen_new_label();
    tcg_gen_brcondi_tl(TCG_COND_EQ, cpu_vl, 0, over);

    dest = tcg_temp_new_ptr();
    mask = tcg_temp_new_ptr();
    base = tcg_temp_new();
    desc = tcg_const_i32(simd_desc(0, s->vlen / 8, data));

    gen_get_gpr(base, rs1);
    tcg_gen_addi_ptr(dest, cpu_env, vreg_ofs(s, vd));
    tcg_gen_addi_ptr(mask, cpu_env, vreg_ofs(s, 0));

    fn(dest, mask, base, cpu_env, desc);

    tcg_temp_free_ptr(dest);
    tcg_temp_free_ptr(mask);
    tcg_temp_free(base);
    tcg_temp_free_i32(desc);
    gen_set_label(over);
    return true;
}

static bool ldff_op(DisasContext *s, arg_r2nfvm *a, uint8_t seq)
{
    uint32_t data = 0;
    gen_helper_ldst_us *fn;
    static gen_helper_ldst_us * const fns[7][4] = {
        { gen_helper_vlbff_v_b,  gen_helper_vlbff_v_h,
          gen_helper_vlbff_v_w,  gen_helper_vlbff_v_d },
        { NULL,                  gen_helper_vlhff_v_h,
          gen_helper_vlhff_v_w,  gen_helper_vlhff_v_d },
        { NULL,                  NULL,
          gen_helper_vlwff_v_w,  gen_helper_vlwff_v_d },
        { gen_helper_vleff_v_b,  gen_helper_vleff_v_h,
          gen_helper_vleff_v_w,  gen_helper_vleff_v_d },
        { gen_helper_vlbuff_v_b, gen_helper_vlbuff_v_h,
          gen_helper_vlbuff_v_w, gen_helper_vlbuff_v_d },
        { NULL,                  gen_helper_vlhuff_v_h,
          gen_helper_vlhuff_v_w, gen_helper_vlhuff_v_d },
        { NULL,                  NULL,
          gen_helper_vlwuff_v_w, gen_helper_vlwuff_v_d }
    };

    fn =  fns[seq][s->sew];
    if (fn == NULL) {
        return false;
    }

    data = FIELD_DP32(data, VDATA, MLEN, s->mlen);
    data = FIELD_DP32(data, VDATA, VM, a->vm);
    data = FIELD_DP32(data, VDATA, LMUL, s->lmul);
    data = FIELD_DP32(data, VDATA, NF, a->nf);
    return ldff_trans(a->rd, a->rs1, data, fn, s);
}

GEN_VEXT_TRANS(vlbff_v, 0, r2nfvm, ldff_op, ld_us_check)
GEN_VEXT_TRANS(vlhff_v, 1, r2nfvm, ldff_op, ld_us_check)
GEN_VEXT_TRANS(vlwff_v, 2, r2nfvm, ldff_op, ld_us_check)
GEN_VEXT_TRANS(vleff_v, 3, r2nfvm, ldff_op, ld_us_check)
GEN_VEXT_TRANS(vlbuff_v, 4, r2nfvm, ldff_op, ld_us_check)
GEN_VEXT_TRANS(vlhuff_v, 5, r2nfvm, ldff_op, ld_us_check)
GEN_VEXT_TRANS(vlwuff_v, 6, r2nfvm, ldff_op, ld_us_check)