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b3a5d1fbeb
Mult are generated inline (using a cool trick pointed out by Richard), but for div and rem, given the complexity of the implementation of these instructions, we call helpers to produce their behavior. From an implementation standpoint, the helpers return the low part of the results, while the high part is temporarily stored in a dedicated field of cpu_env that is used to update the architectural register in the generation wrapper. Signed-off-by: Frédéric Pétrot <frederic.petrot@univ-grenoble-alpes.fr> Co-authored-by: Fabien Portas <fabien.portas@grenoble-inp.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-id: 20220106210108.138226-15-frederic.petrot@univ-grenoble-alpes.fr Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
/*
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* RISC-V Emulation Helpers for QEMU.
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*
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* Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
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* Copyright (c) 2017-2018 SiFive, Inc.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2 or later, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "cpu.h"
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#include "qemu/main-loop.h"
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#include "exec/exec-all.h"
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#include "exec/helper-proto.h"
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target_ulong HELPER(divu_i128)(CPURISCVState *env,
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target_ulong ul, target_ulong uh,
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target_ulong vl, target_ulong vh)
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{
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target_ulong ql, qh;
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Int128 q;
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if (vl == 0 && vh == 0) { /* Handle special behavior on div by zero */
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ql = ~0x0;
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qh = ~0x0;
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} else {
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q = int128_divu(int128_make128(ul, uh), int128_make128(vl, vh));
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ql = int128_getlo(q);
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qh = int128_gethi(q);
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}
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env->retxh = qh;
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return ql;
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}
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target_ulong HELPER(remu_i128)(CPURISCVState *env,
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target_ulong ul, target_ulong uh,
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target_ulong vl, target_ulong vh)
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{
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target_ulong rl, rh;
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Int128 r;
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if (vl == 0 && vh == 0) {
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rl = ul;
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rh = uh;
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} else {
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r = int128_remu(int128_make128(ul, uh), int128_make128(vl, vh));
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rl = int128_getlo(r);
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rh = int128_gethi(r);
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}
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env->retxh = rh;
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return rl;
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}
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target_ulong HELPER(divs_i128)(CPURISCVState *env,
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target_ulong ul, target_ulong uh,
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target_ulong vl, target_ulong vh)
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{
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target_ulong qh, ql;
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Int128 q;
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if (vl == 0 && vh == 0) { /* Div by zero check */
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ql = ~0x0;
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qh = ~0x0;
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} else if (uh == (1ULL << (TARGET_LONG_BITS - 1)) && ul == 0 &&
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vh == ~0x0 && vl == ~0x0) {
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/* Signed div overflow check (-2**127 / -1) */
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ql = ul;
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qh = uh;
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} else {
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q = int128_divs(int128_make128(ul, uh), int128_make128(vl, vh));
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ql = int128_getlo(q);
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qh = int128_gethi(q);
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}
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env->retxh = qh;
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return ql;
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}
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target_ulong HELPER(rems_i128)(CPURISCVState *env,
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target_ulong ul, target_ulong uh,
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target_ulong vl, target_ulong vh)
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{
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target_ulong rh, rl;
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Int128 r;
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if (vl == 0 && vh == 0) {
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rl = ul;
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rh = uh;
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} else {
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r = int128_rems(int128_make128(ul, uh), int128_make128(vl, vh));
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rl = int128_getlo(r);
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rh = int128_gethi(r);
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}
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env->retxh = rh;
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return rl;
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}
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