target/arm: Implement MVE VLDR/VSTR (non-widening forms)

Implement the forms of the MVE VLDR and VSTR insns which perform
non-widening loads of bytes, halfwords or words from memory into
vector elements of the same width (encodings T5, T6, T7).

(At the moment we know for MVE and M-profile in general that
vfp_access_check() can never return false, but we include the
conventional return-true-on-failure check for consistency
with non-M-profile translation code.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-2-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2021-06-17 13:15:45 +01:00
parent 88137f787f
commit 507b6a500c
7 changed files with 351 additions and 0 deletions

24
target/arm/helper-mve.h Normal file
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@ -0,0 +1,24 @@
/*
* M-profile MVE specific helper definitions
*
* Copyright (c) 2021 Linaro, Ltd.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
DEF_HELPER_FLAGS_3(mve_vldrb, TCG_CALL_NO_WG, void, env, ptr, i32)
DEF_HELPER_FLAGS_3(mve_vldrh, TCG_CALL_NO_WG, void, env, ptr, i32)
DEF_HELPER_FLAGS_3(mve_vldrw, TCG_CALL_NO_WG, void, env, ptr, i32)
DEF_HELPER_FLAGS_3(mve_vstrb, TCG_CALL_NO_WG, void, env, ptr, i32)
DEF_HELPER_FLAGS_3(mve_vstrh, TCG_CALL_NO_WG, void, env, ptr, i32)
DEF_HELPER_FLAGS_3(mve_vstrw, TCG_CALL_NO_WG, void, env, ptr, i32)

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@ -1019,3 +1019,5 @@ DEF_HELPER_FLAGS_6(gvec_bfmlal_idx, TCG_CALL_NO_RWG,
#include "helper-a64.h"
#include "helper-sve.h"
#endif
#include "helper-mve.h"

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@ -1202,4 +1202,15 @@ static inline uint64_t useronly_maybe_clean_ptr(uint32_t desc, uint64_t ptr)
return ptr;
}
/* Values for M-profile PSR.ECI for MVE insns */
enum MVEECIState {
ECI_NONE = 0, /* No completed beats */
ECI_A0 = 1, /* Completed: A0 */
ECI_A0A1 = 2, /* Completed: A0, A1 */
/* 3 is reserved */
ECI_A0A1A2 = 4, /* Completed: A0, A1, A2 */
ECI_A0A1A2B0 = 5, /* Completed: A0, A1, A2, B0 */
/* All other values reserved */
};
#endif

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@ -23,6 +23,7 @@ arm_ss.add(files(
'helper.c',
'iwmmxt_helper.c',
'm_helper.c',
'mve_helper.c',
'neon_helper.c',
'op_helper.c',
'tlb_helper.c',

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@ -18,3 +18,25 @@
#
# This file is processed by scripts/decodetree.py
#
%qd 22:1 13:3
&vldr_vstr rn qd imm p a w size l
@vldr_vstr ....... . . . . l:1 rn:4 ... ...... imm:7 &vldr_vstr qd=%qd
# Vector loads and stores
# Non-widening loads/stores (P=0 W=0 is 'related encoding')
VLDR_VSTR 1110110 0 a:1 . 1 . .... ... 111100 ....... @vldr_vstr \
size=0 p=0 w=1
VLDR_VSTR 1110110 0 a:1 . 1 . .... ... 111101 ....... @vldr_vstr \
size=1 p=0 w=1
VLDR_VSTR 1110110 0 a:1 . 1 . .... ... 111110 ....... @vldr_vstr \
size=2 p=0 w=1
VLDR_VSTR 1110110 1 a:1 . w:1 . .... ... 111100 ....... @vldr_vstr \
size=0 p=1
VLDR_VSTR 1110110 1 a:1 . w:1 . .... ... 111101 ....... @vldr_vstr \
size=1 p=1
VLDR_VSTR 1110110 1 a:1 . w:1 . .... ... 111110 ....... @vldr_vstr \
size=2 p=1

172
target/arm/mve_helper.c Normal file
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@ -0,0 +1,172 @@
/*
* M-profile MVE Operations
*
* Copyright (c) 2021 Linaro, Ltd.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "internals.h"
#include "vec_internal.h"
#include "exec/helper-proto.h"
#include "exec/cpu_ldst.h"
#include "exec/exec-all.h"
static uint16_t mve_element_mask(CPUARMState *env)
{
/*
* Return the mask of which elements in the MVE vector should be
* updated. This is a combination of multiple things:
* (1) by default, we update every lane in the vector
* (2) VPT predication stores its state in the VPR register;
* (3) low-overhead-branch tail predication will mask out part
* the vector on the final iteration of the loop
* (4) if EPSR.ECI is set then we must execute only some beats
* of the insn
* We combine all these into a 16-bit result with the same semantics
* as VPR.P0: 0 to mask the lane, 1 if it is active.
* 8-bit vector ops will look at all bits of the result;
* 16-bit ops will look at bits 0, 2, 4, ...;
* 32-bit ops will look at bits 0, 4, 8 and 12.
* Compare pseudocode GetCurInstrBeat(), though that only returns
* the 4-bit slice of the mask corresponding to a single beat.
*/
uint16_t mask = FIELD_EX32(env->v7m.vpr, V7M_VPR, P0);
if (!(env->v7m.vpr & R_V7M_VPR_MASK01_MASK)) {
mask |= 0xff;
}
if (!(env->v7m.vpr & R_V7M_VPR_MASK23_MASK)) {
mask |= 0xff00;
}
if (env->v7m.ltpsize < 4 &&
env->regs[14] <= (1 << (4 - env->v7m.ltpsize))) {
/*
* Tail predication active, and this is the last loop iteration.
* The element size is (1 << ltpsize), and we only want to process
* loopcount elements, so we want to retain the least significant
* (loopcount * esize) predicate bits and zero out bits above that.
*/
int masklen = env->regs[14] << env->v7m.ltpsize;
assert(masklen <= 16);
mask &= MAKE_64BIT_MASK(0, masklen);
}
if ((env->condexec_bits & 0xf) == 0) {
/*
* ECI bits indicate which beats are already executed;
* we handle this by effectively predicating them out.
*/
int eci = env->condexec_bits >> 4;
switch (eci) {
case ECI_NONE:
break;
case ECI_A0:
mask &= 0xfff0;
break;
case ECI_A0A1:
mask &= 0xff00;
break;
case ECI_A0A1A2:
case ECI_A0A1A2B0:
mask &= 0xf000;
break;
default:
g_assert_not_reached();
}
}
return mask;
}
static void mve_advance_vpt(CPUARMState *env)
{
/* Advance the VPT and ECI state if necessary */
uint32_t vpr = env->v7m.vpr;
unsigned mask01, mask23;
if ((env->condexec_bits & 0xf) == 0) {
env->condexec_bits = (env->condexec_bits == (ECI_A0A1A2B0 << 4)) ?
(ECI_A0 << 4) : (ECI_NONE << 4);
}
if (!(vpr & (R_V7M_VPR_MASK01_MASK | R_V7M_VPR_MASK23_MASK))) {
/* VPT not enabled, nothing to do */
return;
}
mask01 = FIELD_EX32(vpr, V7M_VPR, MASK01);
mask23 = FIELD_EX32(vpr, V7M_VPR, MASK23);
if (mask01 > 8) {
/* high bit set, but not 0b1000: invert the relevant half of P0 */
vpr ^= 0xff;
}
if (mask23 > 8) {
/* high bit set, but not 0b1000: invert the relevant half of P0 */
vpr ^= 0xff00;
}
vpr = FIELD_DP32(vpr, V7M_VPR, MASK01, mask01 << 1);
vpr = FIELD_DP32(vpr, V7M_VPR, MASK23, mask23 << 1);
env->v7m.vpr = vpr;
}
#define DO_VLDR(OP, MSIZE, LDTYPE, ESIZE, TYPE) \
void HELPER(mve_##OP)(CPUARMState *env, void *vd, uint32_t addr) \
{ \
TYPE *d = vd; \
uint16_t mask = mve_element_mask(env); \
unsigned b, e; \
/* \
* R_SXTM allows the dest reg to become UNKNOWN for abandoned \
* beats so we don't care if we update part of the dest and \
* then take an exception. \
*/ \
for (b = 0, e = 0; b < 16; b += ESIZE, e++) { \
if (mask & (1 << b)) { \
d[H##ESIZE(e)] = cpu_##LDTYPE##_data_ra(env, addr, GETPC()); \
} \
addr += MSIZE; \
} \
mve_advance_vpt(env); \
}
#define DO_VSTR(OP, MSIZE, STTYPE, ESIZE, TYPE) \
void HELPER(mve_##OP)(CPUARMState *env, void *vd, uint32_t addr) \
{ \
TYPE *d = vd; \
uint16_t mask = mve_element_mask(env); \
unsigned b, e; \
for (b = 0, e = 0; b < 16; b += ESIZE, e++) { \
if (mask & (1 << b)) { \
cpu_##STTYPE##_data_ra(env, addr, d[H##ESIZE(e)], GETPC()); \
} \
addr += MSIZE; \
} \
mve_advance_vpt(env); \
}
DO_VLDR(vldrb, 1, ldub, 1, uint8_t)
DO_VLDR(vldrh, 2, lduw, 2, uint16_t)
DO_VLDR(vldrw, 4, ldl, 4, uint32_t)
DO_VSTR(vstrb, 1, stb, 1, uint8_t)
DO_VSTR(vstrh, 2, stw, 2, uint16_t)
DO_VSTR(vstrw, 4, stl, 4, uint32_t)
#undef DO_VLDR
#undef DO_VSTR

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@ -27,3 +27,122 @@
/* Include the generated decoder */
#include "decode-mve.c.inc"
typedef void MVEGenLdStFn(TCGv_ptr, TCGv_ptr, TCGv_i32);
/* Return the offset of a Qn register (same semantics as aa32_vfp_qreg()) */
static inline long mve_qreg_offset(unsigned reg)
{
return offsetof(CPUARMState, vfp.zregs[reg].d[0]);
}
static TCGv_ptr mve_qreg_ptr(unsigned reg)
{
TCGv_ptr ret = tcg_temp_new_ptr();
tcg_gen_addi_ptr(ret, cpu_env, mve_qreg_offset(reg));
return ret;
}
static bool mve_check_qreg_bank(DisasContext *s, int qmask)
{
/*
* Check whether Qregs are in range. For v8.1M only Q0..Q7
* are supported, see VFPSmallRegisterBank().
*/
return qmask < 8;
}
static bool mve_eci_check(DisasContext *s)
{
/*
* This is a beatwise insn: check that ECI is valid (not a
* reserved value) and note that we are handling it.
* Return true if OK, false if we generated an exception.
*/
s->eci_handled = true;
switch (s->eci) {
case ECI_NONE:
case ECI_A0:
case ECI_A0A1:
case ECI_A0A1A2:
case ECI_A0A1A2B0:
return true;
default:
/* Reserved value: INVSTATE UsageFault */
gen_exception_insn(s, s->pc_curr, EXCP_INVSTATE, syn_uncategorized(),
default_exception_el(s));
return false;
}
}
static void mve_update_eci(DisasContext *s)
{
/*
* The helper function will always update the CPUState field,
* so we only need to update the DisasContext field.
*/
if (s->eci) {
s->eci = (s->eci == ECI_A0A1A2B0) ? ECI_A0 : ECI_NONE;
}
}
static bool do_ldst(DisasContext *s, arg_VLDR_VSTR *a, MVEGenLdStFn *fn)
{
TCGv_i32 addr;
uint32_t offset;
TCGv_ptr qreg;
if (!dc_isar_feature(aa32_mve, s) ||
!mve_check_qreg_bank(s, a->qd) ||
!fn) {
return false;
}
/* CONSTRAINED UNPREDICTABLE: we choose to UNDEF */
if (a->rn == 15 || (a->rn == 13 && a->w)) {
return false;
}
if (!mve_eci_check(s) || !vfp_access_check(s)) {
return true;
}
offset = a->imm << a->size;
if (!a->a) {
offset = -offset;
}
addr = load_reg(s, a->rn);
if (a->p) {
tcg_gen_addi_i32(addr, addr, offset);
}
qreg = mve_qreg_ptr(a->qd);
fn(cpu_env, qreg, addr);
tcg_temp_free_ptr(qreg);
/*
* Writeback always happens after the last beat of the insn,
* regardless of predication
*/
if (a->w) {
if (!a->p) {
tcg_gen_addi_i32(addr, addr, offset);
}
store_reg(s, a->rn, addr);
} else {
tcg_temp_free_i32(addr);
}
mve_update_eci(s);
return true;
}
static bool trans_VLDR_VSTR(DisasContext *s, arg_VLDR_VSTR *a)
{
static MVEGenLdStFn * const ldstfns[4][2] = {
{ gen_helper_mve_vstrb, gen_helper_mve_vldrb },
{ gen_helper_mve_vstrh, gen_helper_mve_vldrh },
{ gen_helper_mve_vstrw, gen_helper_mve_vldrw },
{ NULL, NULL }
};
return do_ldst(s, a, ldstfns[a->size][a->l]);
}