target/riscv/vector_helper.c

/*
 * RISC-V Vector Extension Helpers for QEMU.
 *
 * 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 "qemu/osdep.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "exec/helper-proto.h"
#include <math.h>

target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
                            target_ulong s2)
{
    int vlmax, vl;
    RISCVCPU *cpu = env_archcpu(env);
    uint16_t sew = 8 << FIELD_EX64(s2, VTYPE, VSEW);
    uint8_t ediv = FIELD_EX64(s2, VTYPE, VEDIV);
    bool vill = FIELD_EX64(s2, VTYPE, VILL);
    target_ulong reserved = FIELD_EX64(s2, VTYPE, RESERVED);

    if ((sew > cpu->cfg.elen) || vill || (ediv != 0) || (reserved != 0)) {
        /* only set vill bit. */
        env->vtype = FIELD_DP64(0, VTYPE, VILL, 1);
        env->vl = 0;
        env->vstart = 0;
        return 0;
    }

    vlmax = vext_get_vlmax(cpu, s2);
    if (s1 <= vlmax) {
        vl = s1;
    } else {
        vl = vlmax;
    }
    env->vl = vl;
    env->vtype = s2;
    env->vstart = 0;
    return vl;
}