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target/riscv: rvb: generalized reverse

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Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210505160620.15723-13-frank.chang@sifive.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Frank Chang 2021-05-06 00:06:13 +08:00 • committed by Alistair Francis
parent e58529a8d0
commit 831ec7f3d1
6 changed files with 132 additions and 0 deletions
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64
target/riscv/bitmanip_helper.c Normal file
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/*
* RISC-V Bitmanip Extension Helpers for QEMU.
*
* Copyright (c) 2020 Kito Cheng, kito.cheng@sifive.com
* Copyright (c) 2020 Frank Chang, frank.chang@sifive.com
*
* 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 "qemu/host-utils.h"
#include "exec/exec-all.h"
#include "exec/helper-proto.h"
#include "tcg/tcg.h"
static const uint64_t adjacent_masks[] = {
dup_const(MO_8, 0x55),
dup_const(MO_8, 0x33),
dup_const(MO_8, 0x0f),
dup_const(MO_16, 0xff),
dup_const(MO_32, 0xffff),
UINT32_MAX
};
static inline target_ulong do_swap(target_ulong x, uint64_t mask, int shift)
{
return ((x & mask) << shift) | ((x & ~mask) >> shift);
}
static target_ulong do_grev(target_ulong rs1,
target_ulong rs2,
int bits)
{
target_ulong x = rs1;
int i, shift;
for (i = 0, shift = 1; shift < bits; i++, shift <<= 1) {
if (rs2 & shift) {
x = do_swap(x, adjacent_masks[i], shift);
}
}
return x;
}
target_ulong HELPER(grev)(target_ulong rs1, target_ulong rs2)
{
return do_grev(rs1, rs2, TARGET_LONG_BITS);
}
target_ulong HELPER(grevw)(target_ulong rs1, target_ulong rs2)
{
return do_grev(rs1, rs2, 32);
}