/*
* 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)
DO_VLDR(vldrb_sh, 1, ldsb, 2, int16_t)
DO_VLDR(vldrb_sw, 1, ldsb, 4, int32_t)
DO_VLDR(vldrb_uh, 1, ldub, 2, uint16_t)
DO_VLDR(vldrb_uw, 1, ldub, 4, uint32_t)
DO_VLDR(vldrh_sw, 2, ldsw, 4, int32_t)
DO_VLDR(vldrh_uw, 2, lduw, 4, uint32_t)
DO_VSTR(vstrb_h, 1, stb, 2, int16_t)
DO_VSTR(vstrb_w, 1, stb, 4, int32_t)
DO_VSTR(vstrh_w, 2, stw, 4, int32_t)
#undef DO_VLDR
#undef DO_VSTR
/*
* The mergemask(D, R, M) macro performs the operation "*D = R" but
* storing only the bytes which correspond to 1 bits in M,
* leaving other bytes in *D unchanged. We use _Generic
* to select the correct implementation based on the type of D.
*/
static void mergemask_ub(uint8_t *d, uint8_t r, uint16_t mask)
{
if (mask & 1) {
*d = r;
}
}
static void mergemask_sb(int8_t *d, int8_t r, uint16_t mask)
{
mergemask_ub((uint8_t *)d, r, mask);
}
static void mergemask_uh(uint16_t *d, uint16_t r, uint16_t mask)
{
uint16_t bmask = expand_pred_b_data[mask & 3];
*d = (*d & ~bmask) | (r & bmask);
}
static void mergemask_sh(int16_t *d, int16_t r, uint16_t mask)
{
mergemask_uh((uint16_t *)d, r, mask);
}
static void mergemask_uw(uint32_t *d, uint32_t r, uint16_t mask)
{
uint32_t bmask = expand_pred_b_data[mask & 0xf];
*d = (*d & ~bmask) | (r & bmask);
}
static void mergemask_sw(int32_t *d, int32_t r, uint16_t mask)
{
mergemask_uw((uint32_t *)d, r, mask);
}
static void mergemask_uq(uint64_t *d, uint64_t r, uint16_t mask)
{
uint64_t bmask = expand_pred_b_data[mask & 0xff];
*d = (*d & ~bmask) | (r & bmask);
}
static void mergemask_sq(int64_t *d, int64_t r, uint16_t mask)
{
mergemask_uq((uint64_t *)d, r, mask);
}
#define mergemask(D, R, M) \
_Generic(D, \
uint8_t *: mergemask_ub, \
int8_t *: mergemask_sb, \
uint16_t *: mergemask_uh, \
int16_t *: mergemask_sh, \
uint32_t *: mergemask_uw, \
int32_t *: mergemask_sw, \
uint64_t *: mergemask_uq, \
int64_t *: mergemask_sq)(D, R, M)
#define DO_1OP(OP, ESIZE, TYPE, FN) \
void HELPER(mve_##OP)(CPUARMState *env, void *vd, void *vm) \
{ \
TYPE *d = vd, *m = vm; \
uint16_t mask = mve_element_mask(env); \
unsigned e; \
for (e = 0; e < 16 / ESIZE; e++, mask >>= ESIZE) { \
mergemask(&d[H##ESIZE(e)], FN(m[H##ESIZE(e)]), mask); \
} \
mve_advance_vpt(env); \
}
#define DO_CLZ_B(N) (clz32(N) - 24)
#define DO_CLZ_H(N) (clz32(N) - 16)
DO_1OP(vclzb, 1, uint8_t, DO_CLZ_B)
DO_1OP(vclzh, 2, uint16_t, DO_CLZ_H)
DO_1OP(vclzw, 4, uint32_t, clz32)
