df4252b2ec
We're going to make changes that will required each helper to be responsible for the 'vstart' management, i.e. we will relieve the 'vstart < vl' assumption that helpers have today. Helpers are usually able to deal with vstart >= vl, i.e. doing nothing aside from setting vstart = 0 at the end, but the tail update functions will update the tail regardless of vstart being valid or not. Unifying the tail update process in a single function that would handle the vstart >= vl case isn't trivial (see [1] for more info). This patch takes a blunt approach: do an early exit in every single vector helper if vstart >= vl, unless the helper is guarded with vstart_eq_zero in the translation. For those cases the helper is ready to deal with cases where vl might be zero, i.e. throwing exceptions based on it like vcpop_m() and first_m(). Helpers that weren't changed: - vcpop_m(), vfirst_m(), vmsetm(), GEN_VEXT_VIOTA_M(): these are guarded directly with vstart_eq_zero; - GEN_VEXT_VCOMPRESS_VM(): guarded with vcompress_vm_check() that checks vstart_eq_zero; - GEN_VEXT_RED(): guarded with either reduction_check() or reduction_widen_check(), both check vstart_eq_zero; - GEN_VEXT_FRED(): guarded with either freduction_check() or freduction_widen_check(), both check vstart_eq_zero. Another exception is vext_ldst_whole(), who operates on effective vector length regardless of the current settings in vtype and vl. [1] https://lore.kernel.org/qemu-riscv/1590234b-0291-432a-a0fa-c5a6876097bc@linux.alibaba.com/ Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com> Acked-by: Alistair Francis <alistair.francis@wdc.com> Message-ID: <20240314175704.478276-7-dbarboza@ventanamicro.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
87 lines
2.6 KiB
C
87 lines
2.6 KiB
C
/*
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* RISC-V Vector Extension Internals
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*
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* Copyright (c) 2020 T-Head Semiconductor Co., Ltd. All rights reserved.
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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 "vector_internals.h"
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/* set agnostic elements to 1s */
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void vext_set_elems_1s(void *base, uint32_t is_agnostic, uint32_t cnt,
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uint32_t tot)
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{
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if (is_agnostic == 0) {
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/* policy undisturbed */
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return;
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}
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if (tot - cnt == 0) {
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return ;
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}
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memset(base + cnt, -1, tot - cnt);
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}
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void do_vext_vv(void *vd, void *v0, void *vs1, void *vs2,
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CPURISCVState *env, uint32_t desc,
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opivv2_fn *fn, uint32_t esz)
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{
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uint32_t vm = vext_vm(desc);
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uint32_t vl = env->vl;
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uint32_t total_elems = vext_get_total_elems(env, desc, esz);
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uint32_t vta = vext_vta(desc);
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uint32_t vma = vext_vma(desc);
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uint32_t i;
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VSTART_CHECK_EARLY_EXIT(env);
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for (i = env->vstart; i < vl; i++) {
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if (!vm && !vext_elem_mask(v0, i)) {
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/* set masked-off elements to 1s */
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vext_set_elems_1s(vd, vma, i * esz, (i + 1) * esz);
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continue;
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}
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fn(vd, vs1, vs2, i);
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}
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env->vstart = 0;
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/* set tail elements to 1s */
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vext_set_elems_1s(vd, vta, vl * esz, total_elems * esz);
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}
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void do_vext_vx(void *vd, void *v0, target_long s1, void *vs2,
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CPURISCVState *env, uint32_t desc,
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opivx2_fn fn, uint32_t esz)
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{
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uint32_t vm = vext_vm(desc);
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uint32_t vl = env->vl;
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uint32_t total_elems = vext_get_total_elems(env, desc, esz);
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uint32_t vta = vext_vta(desc);
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uint32_t vma = vext_vma(desc);
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uint32_t i;
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VSTART_CHECK_EARLY_EXIT(env);
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for (i = env->vstart; i < vl; i++) {
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if (!vm && !vext_elem_mask(v0, i)) {
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/* set masked-off elements to 1s */
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vext_set_elems_1s(vd, vma, i * esz, (i + 1) * esz);
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continue;
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}
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fn(vd, s1, vs2, i);
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}
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env->vstart = 0;
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/* set tail elements to 1s */
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vext_set_elems_1s(vd, vta, vl * esz, total_elems * esz);
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}
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