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qemu/target/hexagon/decode.c
Taylor Simpson fb67c2bf24 Hexagon (target/hexagon) Only use branch_taken when packet has multi cof 
When a packet has more than one change-of-flow instruction, only the first
one to branch is considered.  We use the branch_taken variable to keep
track of this.

However, when there is a single cof instruction, we don't need the same
amount of bookkeeping.

We add the pkt_has_multi_cof member to the Packet structure, and pass this
information to the needed functions.

When there is a generated helper function with cof, the generator will
pass this pkt_has_multi_cof as a runtime value.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <20221108162906.3166-5-tsimpson@quicinc.com>
2022-12-16 10:10:28 -08:00

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/*
* Copyright(c) 2019-2022 Qualcomm Innovation Center, Inc. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 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 "iclass.h"
#include "attribs.h"
#include "genptr.h"
#include "decode.h"
#include "insn.h"
#include "printinsn.h"
#include "mmvec/decode_ext_mmvec.h"
#define fZXTN(N, M, VAL) ((VAL) & ((1LL << (N)) - 1))
enum {
EXT_IDX_noext = 0,
EXT_IDX_noext_AFTER = 4,
EXT_IDX_mmvec = 4,
EXT_IDX_mmvec_AFTER = 8,
XX_LAST_EXT_IDX
};
/*
* Certain operand types represent a non-contiguous set of values.
* For example, the compound compare-and-jump instruction can only access
* registers R0-R7 and R16-23.
* This table represents the mapping from the encoding to the actual values.
*/
#define DEF_REGMAP(NAME, ELEMENTS, ...) \
static const unsigned int DECODE_REGISTER_##NAME[ELEMENTS] = \
{ __VA_ARGS__ };
/* Name Num Table */
DEF_REGMAP(R_16, 16, 0, 1, 2, 3, 4, 5, 6, 7, 16, 17, 18, 19, 20, 21, 22, 23)
DEF_REGMAP(R__8, 8, 0, 2, 4, 6, 16, 18, 20, 22)
DEF_REGMAP(R_8, 8, 0, 1, 2, 3, 4, 5, 6, 7)
#define DECODE_MAPPED_REG(OPNUM, NAME) \
insn->regno[OPNUM] = DECODE_REGISTER_##NAME[insn->regno[OPNUM]];
typedef struct {
const struct DectreeTable *table_link;
const struct DectreeTable *table_link_b;
Opcode opcode;
enum {
DECTREE_ENTRY_INVALID,
DECTREE_TABLE_LINK,
DECTREE_SUBINSNS,
DECTREE_EXTSPACE,
DECTREE_TERMINAL
} type;
} DectreeEntry;
typedef struct DectreeTable {
unsigned int (*lookup_function)(int startbit, int width, uint32_t opcode);
unsigned int size;
unsigned int startbit;
unsigned int width;
const DectreeEntry table[];
} DectreeTable;
#define DECODE_NEW_TABLE(TAG, SIZE, WHATNOT) \
static const DectreeTable dectree_table_##TAG;
#define TABLE_LINK(TABLE) /* NOTHING */
#define TERMINAL(TAG, ENC) /* NOTHING */
#define SUBINSNS(TAG, CLASSA, CLASSB, ENC) /* NOTHING */
#define EXTSPACE(TAG, ENC) /* NOTHING */
#define INVALID() /* NOTHING */
#define DECODE_END_TABLE(...) /* NOTHING */
#define DECODE_MATCH_INFO(...) /* NOTHING */
#define DECODE_LEGACY_MATCH_INFO(...) /* NOTHING */
#define DECODE_OPINFO(...) /* NOTHING */
#include "dectree_generated.h.inc"
#undef DECODE_OPINFO
#undef DECODE_MATCH_INFO
#undef DECODE_LEGACY_MATCH_INFO
#undef DECODE_END_TABLE
#undef INVALID
#undef TERMINAL
#undef SUBINSNS
#undef EXTSPACE
#undef TABLE_LINK
#undef DECODE_NEW_TABLE
#undef DECODE_SEPARATOR_BITS
#define DECODE_SEPARATOR_BITS(START, WIDTH) NULL, START, WIDTH
#define DECODE_NEW_TABLE_HELPER(TAG, SIZE, FN, START, WIDTH) \
static const DectreeTable dectree_table_##TAG = { \
.size = SIZE, \
.lookup_function = FN, \
.startbit = START, \
.width = WIDTH, \
.table = {
#define DECODE_NEW_TABLE(TAG, SIZE, WHATNOT) \
DECODE_NEW_TABLE_HELPER(TAG, SIZE, WHATNOT)
#define TABLE_LINK(TABLE) \
{ .type = DECTREE_TABLE_LINK, .table_link = &dectree_table_##TABLE },
#define TERMINAL(TAG, ENC) \
{ .type = DECTREE_TERMINAL, .opcode = TAG },
#define SUBINSNS(TAG, CLASSA, CLASSB, ENC) \
{ \
.type = DECTREE_SUBINSNS, \
.table_link = &dectree_table_DECODE_SUBINSN_##CLASSA, \
.table_link_b = &dectree_table_DECODE_SUBINSN_##CLASSB \
},
#define EXTSPACE(TAG, ENC) { .type = DECTREE_EXTSPACE },
#define INVALID() { .type = DECTREE_ENTRY_INVALID, .opcode = XX_LAST_OPCODE },
#define DECODE_END_TABLE(...) } };
#define DECODE_MATCH_INFO(...) /* NOTHING */
#define DECODE_LEGACY_MATCH_INFO(...) /* NOTHING */
#define DECODE_OPINFO(...) /* NOTHING */
#include "dectree_generated.h.inc"
#undef DECODE_OPINFO
#undef DECODE_MATCH_INFO
#undef DECODE_LEGACY_MATCH_INFO
#undef DECODE_END_TABLE
#undef INVALID
#undef TERMINAL
#undef SUBINSNS
#undef EXTSPACE
#undef TABLE_LINK
#undef DECODE_NEW_TABLE
#undef DECODE_NEW_TABLE_HELPER
#undef DECODE_SEPARATOR_BITS
static const DectreeTable dectree_table_DECODE_EXT_EXT_noext = {
.size = 1, .lookup_function = NULL, .startbit = 0, .width = 0,
.table = {
{ .type = DECTREE_ENTRY_INVALID, .opcode = XX_LAST_OPCODE },
}
};
static const DectreeTable *ext_trees[XX_LAST_EXT_IDX];
static void decode_ext_init(void)
{
int i;
for (i = EXT_IDX_noext; i < EXT_IDX_noext_AFTER; i++) {
ext_trees[i] = &dectree_table_DECODE_EXT_EXT_noext;
}
for (i = EXT_IDX_mmvec; i < EXT_IDX_mmvec_AFTER; i++) {
ext_trees[i] = &dectree_table_DECODE_EXT_EXT_mmvec;
}
}
typedef struct {
uint32_t mask;
uint32_t match;
} DecodeITableEntry;
#define DECODE_NEW_TABLE(TAG, SIZE, WHATNOT) /* NOTHING */
#define TABLE_LINK(TABLE) /* NOTHING */
#define TERMINAL(TAG, ENC) /* NOTHING */
#define SUBINSNS(TAG, CLASSA, CLASSB, ENC) /* NOTHING */
#define EXTSPACE(TAG, ENC) /* NOTHING */
#define INVALID() /* NOTHING */
#define DECODE_END_TABLE(...) /* NOTHING */
#define DECODE_OPINFO(...) /* NOTHING */
#define DECODE_MATCH_INFO_NORMAL(TAG, MASK, MATCH) \
[TAG] = { \
.mask = MASK, \
.match = MATCH, \
},
#define DECODE_MATCH_INFO_NULL(TAG, MASK, MATCH) \
[TAG] = { .match = ~0 },
#define DECODE_MATCH_INFO(...) DECODE_MATCH_INFO_NORMAL(__VA_ARGS__)
#define DECODE_LEGACY_MATCH_INFO(...) /* NOTHING */
static const DecodeITableEntry decode_itable[XX_LAST_OPCODE] = {
#include "dectree_generated.h.inc"
};
#undef DECODE_MATCH_INFO
#define DECODE_MATCH_INFO(...) DECODE_MATCH_INFO_NULL(__VA_ARGS__)
#undef DECODE_LEGACY_MATCH_INFO
#define DECODE_LEGACY_MATCH_INFO(...) DECODE_MATCH_INFO_NORMAL(__VA_ARGS__)
static const DecodeITableEntry decode_legacy_itable[XX_LAST_OPCODE] = {
#include "dectree_generated.h.inc"
};
#undef DECODE_OPINFO
#undef DECODE_MATCH_INFO
#undef DECODE_LEGACY_MATCH_INFO
#undef DECODE_END_TABLE
#undef INVALID
#undef TERMINAL
#undef SUBINSNS
#undef EXTSPACE
#undef TABLE_LINK
#undef DECODE_NEW_TABLE
#undef DECODE_SEPARATOR_BITS
void decode_init(void)
{
decode_ext_init();
}
void decode_send_insn_to(Packet *packet, int start, int newloc)
{
Insn tmpinsn;
int direction;
int i;
if (start == newloc) {
return;
}
if (start < newloc) {
/* Move towards end */
direction = 1;
} else {
/* move towards beginning */
direction = -1;
}
for (i = start; i != newloc; i += direction) {
tmpinsn = packet->insn[i];
packet->insn[i] = packet->insn[i + direction];
packet->insn[i + direction] = tmpinsn;
}
}
/* Fill newvalue registers with the correct regno */
static void
decode_fill_newvalue_regno(Packet *packet)
{
int i, use_regidx, offset, def_idx, dst_idx;
uint16_t def_opcode, use_opcode;
char *dststr;
for (i = 1; i < packet->num_insns; i++) {
if (GET_ATTRIB(packet->insn[i].opcode, A_DOTNEWVALUE) &&
!GET_ATTRIB(packet->insn[i].opcode, A_EXTENSION)) {
use_opcode = packet->insn[i].opcode;
/* It's a store, so we're adjusting the Nt field */
if (GET_ATTRIB(use_opcode, A_STORE)) {
use_regidx = strchr(opcode_reginfo[use_opcode], 't') -
opcode_reginfo[use_opcode];
} else { /* It's a Jump, so we're adjusting the Ns field */
use_regidx = strchr(opcode_reginfo[use_opcode], 's') -
opcode_reginfo[use_opcode];
}
/*
* What's encoded at the N-field is the offset to who's producing
* the value. Shift off the LSB which indicates odd/even register,
* then walk backwards and skip over the constant extenders.
*/
offset = packet->insn[i].regno[use_regidx] >> 1;
def_idx = i - offset;
for (int j = 0; j < offset; j++) {
if (GET_ATTRIB(packet->insn[i - j - 1].opcode, A_IT_EXTENDER)) {
def_idx--;
}
}
/*
* Check for a badly encoded N-field which points to an instruction
* out-of-range
*/
g_assert(!((def_idx < 0) || (def_idx > (packet->num_insns - 1))));
/*
* packet->insn[def_idx] is the producer
* Figure out which type of destination it produces
* and the corresponding index in the reginfo
*/
def_opcode = packet->insn[def_idx].opcode;
dststr = strstr(opcode_wregs[def_opcode], "Rd");
if (dststr) {
dststr = strchr(opcode_reginfo[def_opcode], 'd');
} else {
dststr = strstr(opcode_wregs[def_opcode], "Rx");
if (dststr) {
dststr = strchr(opcode_reginfo[def_opcode], 'x');
} else {
dststr = strstr(opcode_wregs[def_opcode], "Re");
if (dststr) {
dststr = strchr(opcode_reginfo[def_opcode], 'e');
} else {
dststr = strstr(opcode_wregs[def_opcode], "Ry");
if (dststr) {
dststr = strchr(opcode_reginfo[def_opcode], 'y');
} else {
g_assert_not_reached();
}
}
}
}
g_assert(dststr != NULL);
/* Now patch up the consumer with the register number */
dst_idx = dststr - opcode_reginfo[def_opcode];
packet->insn[i].regno[use_regidx] =
packet->insn[def_idx].regno[dst_idx];
/*
* We need to remember who produces this value to later
* check if it was dynamically cancelled
*/
packet->insn[i].new_value_producer_slot =
packet->insn[def_idx].slot;
}
}
}
/* Split CJ into a compare and a jump */
static void decode_split_cmpjump(Packet *pkt)
{
int last, i;
int numinsns = pkt->num_insns;
/*
* First, split all compare-jumps.
* The compare is sent to the end as a new instruction.
* Do it this way so we don't reorder dual jumps. Those need to stay in
* original order.
*/
for (i = 0; i < numinsns; i++) {
/* It's a cmp-jump */
if (GET_ATTRIB(pkt->insn[i].opcode, A_NEWCMPJUMP)) {
last = pkt->num_insns;
pkt->insn[last] = pkt->insn[i]; /* copy the instruction */
pkt->insn[last].part1 = true; /* last insn does the CMP */
pkt->insn[i].part1 = false; /* existing insn does the JUMP */
pkt->num_insns++;
}
}
/* Now re-shuffle all the compares back to the beginning */
for (i = 0; i < pkt->num_insns; i++) {
if (pkt->insn[i].part1) {
decode_send_insn_to(pkt, i, 0);
}
}
}
static bool decode_opcode_can_jump(int opcode)
{
if ((GET_ATTRIB(opcode, A_JUMP)) ||
(GET_ATTRIB(opcode, A_CALL)) ||
(opcode == J2_trap0) ||
(opcode == J2_pause)) {
/* Exception to A_JUMP attribute */
if (opcode == J4_hintjumpr) {
return false;
}
return true;
}
return false;
}
static bool decode_opcode_ends_loop(int opcode)
{
return GET_ATTRIB(opcode, A_HWLOOP0_END) ||
GET_ATTRIB(opcode, A_HWLOOP1_END);
}
/* Set the is_* fields in each instruction */
static void decode_set_insn_attr_fields(Packet *pkt)
{
int i;
int numinsns = pkt->num_insns;
uint16_t opcode;
pkt->pkt_has_cof = false;
pkt->pkt_has_multi_cof = false;
pkt->pkt_has_endloop = false;
pkt->pkt_has_dczeroa = false;
for (i = 0; i < numinsns; i++) {
opcode = pkt->insn[i].opcode;
if (pkt->insn[i].part1) {
continue; /* Skip compare of cmp-jumps */
}
if (GET_ATTRIB(opcode, A_DCZEROA)) {
pkt->pkt_has_dczeroa = true;
}
if (GET_ATTRIB(opcode, A_STORE)) {
if (GET_ATTRIB(opcode, A_SCALAR_STORE) &&
!GET_ATTRIB(opcode, A_MEMSIZE_0B)) {
if (pkt->insn[i].slot == 0) {
pkt->pkt_has_store_s0 = true;
} else {
pkt->pkt_has_store_s1 = true;
}
}
}
if (decode_opcode_can_jump(opcode)) {
if (pkt->pkt_has_cof) {
pkt->pkt_has_multi_cof = true;
}
pkt->pkt_has_cof = true;
}
pkt->insn[i].is_endloop = decode_opcode_ends_loop(opcode);
pkt->pkt_has_endloop |= pkt->insn[i].is_endloop;
if (pkt->pkt_has_endloop) {
if (pkt->pkt_has_cof) {
pkt->pkt_has_multi_cof = true;
}
pkt->pkt_has_cof = true;
}
}
}
/*
* Shuffle for execution
* Move stores to end (in same order as encoding)
* Move compares to beginning (for use by .new insns)
*/
static void decode_shuffle_for_execution(Packet *packet)
{
bool changed = false;
int i;
bool flag; /* flag means we've seen a non-memory instruction */
int n_mems;
int last_insn = packet->num_insns - 1;
/*
* Skip end loops, somehow an end loop is getting in and messing
* up the order
*/
if (decode_opcode_ends_loop(packet->insn[last_insn].opcode)) {
last_insn--;
}
do {
changed = false;
/*
* Stores go last, must not reorder.
* Cannot shuffle stores past loads, either.
* Iterate backwards. If we see a non-memory instruction,
* then a store, shuffle the store to the front. Don't shuffle
* stores wrt each other or a load.
*/
for (flag = false, n_mems = 0, i = last_insn; i >= 0; i--) {
int opcode = packet->insn[i].opcode;
if (flag && GET_ATTRIB(opcode, A_STORE)) {
decode_send_insn_to(packet, i, last_insn - n_mems);
n_mems++;
changed = true;
} else if (GET_ATTRIB(opcode, A_STORE)) {
n_mems++;
} else if (GET_ATTRIB(opcode, A_LOAD)) {
/*
* Don't set flag, since we don't want to shuffle a
* store past a load
*/
n_mems++;
} else if (GET_ATTRIB(opcode, A_DOTNEWVALUE)) {
/*
* Don't set flag, since we don't want to shuffle past
* a .new value
*/
} else {
flag = true;
}
}
if (changed) {
continue;
}
/* Compares go first, may be reordered wrt each other */
for (flag = false, i = 0; i < last_insn + 1; i++) {
int opcode = packet->insn[i].opcode;
if ((strstr(opcode_wregs[opcode], "Pd4") ||
strstr(opcode_wregs[opcode], "Pe4")) &&
GET_ATTRIB(opcode, A_STORE) == 0) {
/* This should be a compare (not a store conditional) */
if (flag) {
decode_send_insn_to(packet, i, 0);
changed = true;
continue;
}
} else if (GET_ATTRIB(opcode, A_IMPLICIT_WRITES_P3) &&
!decode_opcode_ends_loop(packet->insn[i].opcode)) {
/*
* spNloop instruction
* Don't reorder endloops; they are not valid for .new uses,
* and we want to match HW
*/
if (flag) {
decode_send_insn_to(packet, i, 0);
changed = true;
continue;
}
} else if (GET_ATTRIB(opcode, A_IMPLICIT_WRITES_P0) &&
!GET_ATTRIB(opcode, A_NEWCMPJUMP)) {
if (flag) {
decode_send_insn_to(packet, i, 0);
changed = true;
continue;
}
} else {
flag = true;
}
}
if (changed) {
continue;
}
} while (changed);
/*
* If we have a .new register compare/branch, move that to the very
* very end, past stores
*/
for (i = 0; i < last_insn; i++) {
if (GET_ATTRIB(packet->insn[i].opcode, A_DOTNEWVALUE)) {
decode_send_insn_to(packet, i, last_insn);
break;
}
}
}
static void
apply_extender(Packet *pkt, int i, uint32_t extender)
{
int immed_num;
uint32_t base_immed;
immed_num = opcode_which_immediate_is_extended(pkt->insn[i].opcode);
base_immed = pkt->insn[i].immed[immed_num];
pkt->insn[i].immed[immed_num] = extender | fZXTN(6, 32, base_immed);
}
static void decode_apply_extenders(Packet *packet)
{
int i;
for (i = 0; i < packet->num_insns; i++) {
if (GET_ATTRIB(packet->insn[i].opcode, A_IT_EXTENDER)) {
packet->insn[i + 1].extension_valid = true;
apply_extender(packet, i + 1, packet->insn[i].immed[0]);
}
}
}
static void decode_remove_extenders(Packet *packet)
{
int i, j;
for (i = 0; i < packet->num_insns; i++) {
if (GET_ATTRIB(packet->insn[i].opcode, A_IT_EXTENDER)) {
/* Remove this one by moving the remaining instructions down */
for (j = i;
(j < packet->num_insns - 1) && (j < INSTRUCTIONS_MAX - 1);
j++) {
packet->insn[j] = packet->insn[j + 1];
}
packet->num_insns--;
}
}
}
static SlotMask get_valid_slots(const Packet *pkt, unsigned int slot)
{
if (GET_ATTRIB(pkt->insn[slot].opcode, A_EXTENSION)) {
return mmvec_ext_decode_find_iclass_slots(pkt->insn[slot].opcode);
} else {
return find_iclass_slots(pkt->insn[slot].opcode,
pkt->insn[slot].iclass);
}
}
#define DECODE_NEW_TABLE(TAG, SIZE, WHATNOT) /* NOTHING */
#define TABLE_LINK(TABLE) /* NOTHING */
#define TERMINAL(TAG, ENC) /* NOTHING */
#define SUBINSNS(TAG, CLASSA, CLASSB, ENC) /* NOTHING */
#define EXTSPACE(TAG, ENC) /* NOTHING */
#define INVALID() /* NOTHING */
#define DECODE_END_TABLE(...) /* NOTHING */
#define DECODE_MATCH_INFO(...) /* NOTHING */
#define DECODE_LEGACY_MATCH_INFO(...) /* NOTHING */
#define DECODE_REG(REGNO, WIDTH, STARTBIT) \
insn->regno[REGNO] = ((encoding >> STARTBIT) & ((1 << WIDTH) - 1));
#define DECODE_IMPL_REG(REGNO, VAL) \
insn->regno[REGNO] = VAL;
#define DECODE_IMM(IMMNO, WIDTH, STARTBIT, VALSTART) \
insn->immed[IMMNO] |= (((encoding >> STARTBIT) & ((1 << WIDTH) - 1))) << \
(VALSTART);
#define DECODE_IMM_SXT(IMMNO, WIDTH) \
insn->immed[IMMNO] = ((((int32_t)insn->immed[IMMNO]) << (32 - WIDTH)) >> \
(32 - WIDTH));
#define DECODE_IMM_NEG(IMMNO, WIDTH) \
insn->immed[IMMNO] = -insn->immed[IMMNO];
#define DECODE_IMM_SHIFT(IMMNO, SHAMT) \
if ((!insn->extension_valid) || \
(insn->which_extended != IMMNO)) { \
insn->immed[IMMNO] <<= SHAMT; \
}
#define DECODE_OPINFO(TAG, BEH) \
case TAG: \
{ BEH } \
break; \
/*
* Fill in the operands of the instruction
* dectree_generated.h.inc has a DECODE_OPINFO entry for each opcode
* For example,
* DECODE_OPINFO(A2_addi,
* DECODE_REG(0,5,0)
* DECODE_REG(1,5,16)
* DECODE_IMM(0,7,21,9)
* DECODE_IMM(0,9,5,0)
* DECODE_IMM_SXT(0,16)
* with the macros defined above, we'll fill in a switch statement
* where each case is an opcode tag.
*/
static void
decode_op(Insn *insn, Opcode tag, uint32_t encoding)
{
insn->immed[0] = 0;
insn->immed[1] = 0;
insn->opcode = tag;
if (insn->extension_valid) {
insn->which_extended = opcode_which_immediate_is_extended(tag);
}
switch (tag) {
#include "dectree_generated.h.inc"
default:
break;
}
insn->generate = opcode_genptr[tag];
insn->iclass = iclass_bits(encoding);
}
#undef DECODE_REG
#undef DECODE_IMPL_REG
#undef DECODE_IMM
#undef DECODE_IMM_SHIFT
#undef DECODE_OPINFO
#undef DECODE_MATCH_INFO
#undef DECODE_LEGACY_MATCH_INFO
#undef DECODE_END_TABLE
#undef INVALID
#undef TERMINAL
#undef SUBINSNS
#undef EXTSPACE
#undef TABLE_LINK
#undef DECODE_NEW_TABLE
#undef DECODE_SEPARATOR_BITS
static unsigned int
decode_subinsn_tablewalk(Insn *insn, const DectreeTable *table,
uint32_t encoding)
{
unsigned int i;
Opcode opc;
if (table->lookup_function) {
i = table->lookup_function(table->startbit, table->width, encoding);
} else {
i = extract32(encoding, table->startbit, table->width);
}
if (table->table[i].type == DECTREE_TABLE_LINK) {
return decode_subinsn_tablewalk(insn, table->table[i].table_link,
encoding);
} else if (table->table[i].type == DECTREE_TERMINAL) {
opc = table->table[i].opcode;
if ((encoding & decode_itable[opc].mask) != decode_itable[opc].match) {
return 0;
}
decode_op(insn, opc, encoding);
return 1;
} else {
return 0;
}
}
static unsigned int get_insn_a(uint32_t encoding)
{
return extract32(encoding, 0, 13);
}
static unsigned int get_insn_b(uint32_t encoding)
{
return extract32(encoding, 16, 13);
}
static unsigned int
decode_insns_tablewalk(Insn *insn, const DectreeTable *table,
uint32_t encoding)
{
unsigned int i;
unsigned int a, b;
Opcode opc;
if (table->lookup_function) {
i = table->lookup_function(table->startbit, table->width, encoding);
} else {
i = extract32(encoding, table->startbit, table->width);
}
if (table->table[i].type == DECTREE_TABLE_LINK) {
return decode_insns_tablewalk(insn, table->table[i].table_link,
encoding);
} else if (table->table[i].type == DECTREE_SUBINSNS) {
a = get_insn_a(encoding);
b = get_insn_b(encoding);
b = decode_subinsn_tablewalk(insn, table->table[i].table_link_b, b);
a = decode_subinsn_tablewalk(insn + 1, table->table[i].table_link, a);
if ((a == 0) || (b == 0)) {
return 0;
}
return 2;
} else if (table->table[i].type == DECTREE_TERMINAL) {
opc = table->table[i].opcode;
if ((encoding & decode_itable[opc].mask) != decode_itable[opc].match) {
if ((encoding & decode_legacy_itable[opc].mask) !=
decode_legacy_itable[opc].match) {
return 0;
}
}
decode_op(insn, opc, encoding);
return 1;
} else if (table->table[i].type == DECTREE_EXTSPACE) {
/*
* For now, HVX will be the only coproc
*/
return decode_insns_tablewalk(insn, ext_trees[EXT_IDX_mmvec], encoding);
} else {
return 0;
}
}
static unsigned int
decode_insns(Insn *insn, uint32_t encoding)
{
const DectreeTable *table;
if (parse_bits(encoding) != 0) {
/* Start with PP table - 32 bit instructions */
table = &dectree_table_DECODE_ROOT_32;
} else {
/* start with EE table - duplex instructions */
table = &dectree_table_DECODE_ROOT_EE;
}
return decode_insns_tablewalk(insn, table, encoding);
}
static void decode_add_endloop_insn(Insn *insn, int loopnum)
{
if (loopnum == 10) {
insn->opcode = J2_endloop01;
insn->generate = opcode_genptr[J2_endloop01];
} else if (loopnum == 1) {
insn->opcode = J2_endloop1;
insn->generate = opcode_genptr[J2_endloop1];
} else if (loopnum == 0) {
insn->opcode = J2_endloop0;
insn->generate = opcode_genptr[J2_endloop0];
} else {
g_assert_not_reached();
}
}
static bool decode_parsebits_is_loopend(uint32_t encoding32)
{
uint32_t bits = parse_bits(encoding32);
return bits == 0x2;
}
static void
decode_set_slot_number(Packet *pkt)
{
int slot;
int i;
bool hit_mem_insn = false;
bool hit_duplex = false;
bool slot0_found = false;
bool slot1_found = false;
int slot1_iidx = 0;
/*
* The slots are encoded in reverse order
* For each instruction, count down until you find a suitable slot
*/
for (i = 0, slot = 3; i < pkt->num_insns; i++) {
SlotMask valid_slots = get_valid_slots(pkt, i);
while (!(valid_slots & (1 << slot))) {
slot--;
}
pkt->insn[i].slot = slot;
if (slot) {
/* I've assigned the slot, now decrement it for the next insn */
slot--;
}
}
/* Fix the exceptions - mem insns to slot 0,1 */
for (i = pkt->num_insns - 1; i >= 0; i--) {
/* First memory instruction always goes to slot 0 */
if ((GET_ATTRIB(pkt->insn[i].opcode, A_MEMLIKE) ||
GET_ATTRIB(pkt->insn[i].opcode, A_MEMLIKE_PACKET_RULES)) &&
!hit_mem_insn) {
hit_mem_insn = true;
pkt->insn[i].slot = 0;
continue;
}
/* Next memory instruction always goes to slot 1 */
if ((GET_ATTRIB(pkt->insn[i].opcode, A_MEMLIKE) ||
GET_ATTRIB(pkt->insn[i].opcode, A_MEMLIKE_PACKET_RULES)) &&
hit_mem_insn) {
pkt->insn[i].slot = 1;
}
}
/* Fix the exceptions - duplex always slot 0,1 */
for (i = pkt->num_insns - 1; i >= 0; i--) {
/* First subinsn always goes to slot 0 */
if (GET_ATTRIB(pkt->insn[i].opcode, A_SUBINSN) && !hit_duplex) {
hit_duplex = true;
pkt->insn[i].slot = 0;
continue;
}
/* Next subinsn always goes to slot 1 */
if (GET_ATTRIB(pkt->insn[i].opcode, A_SUBINSN) && hit_duplex) {
pkt->insn[i].slot = 1;
}
}
/* Fix the exceptions - slot 1 is never empty, always aligns to slot 0 */
for (i = pkt->num_insns - 1; i >= 0; i--) {
/* Is slot0 used? */
if (pkt->insn[i].slot == 0) {
bool is_endloop = (pkt->insn[i].opcode == J2_endloop01);
is_endloop |= (pkt->insn[i].opcode == J2_endloop0);
is_endloop |= (pkt->insn[i].opcode == J2_endloop1);
/*
* Make sure it's not endloop since, we're overloading
* slot0 for endloop
*/
if (!is_endloop) {
slot0_found = true;
}
}
/* Is slot1 used? */
if (pkt->insn[i].slot == 1) {
slot1_found = true;
slot1_iidx = i;
}
}
/* Is slot0 empty and slot1 used? */
if ((!slot0_found) && slot1_found) {
/* Then push it to slot0 */
pkt->insn[slot1_iidx].slot = 0;
}
}
/*
* decode_packet
* Decodes packet with given words
* Returns 0 on insufficient words,
* or number of words used on success
*/
int decode_packet(int max_words, const uint32_t *words, Packet *pkt,
bool disas_only)
{
int num_insns = 0;
int words_read = 0;
bool end_of_packet = false;
int new_insns = 0;
int i;
uint32_t encoding32;
/* Initialize */
memset(pkt, 0, sizeof(*pkt));
/* Try to build packet */
while (!end_of_packet && (words_read < max_words)) {
encoding32 = words[words_read];
end_of_packet = is_packet_end(encoding32);
new_insns = decode_insns(&pkt->insn[num_insns], encoding32);
g_assert(new_insns > 0);
/*
* If we saw an extender, mark next word extended so immediate
* decode works
*/
if (pkt->insn[num_insns].opcode == A4_ext) {
pkt->insn[num_insns + 1].extension_valid = true;
}
num_insns += new_insns;
words_read++;
}
pkt->num_insns = num_insns;
if (!end_of_packet) {
/* Ran out of words! */
return 0;
}
pkt->encod_pkt_size_in_bytes = words_read * 4;
pkt->pkt_has_hvx = false;
for (i = 0; i < num_insns; i++) {
pkt->pkt_has_hvx |=
GET_ATTRIB(pkt->insn[i].opcode, A_CVI);
}
/*
* Check for :endloop in the parse bits
* Section 10.6 of the Programmer's Reference describes the encoding
* The end of hardware loop 0 can be encoded with 2 words
* The end of hardware loop 1 needs 3 words
*/
if ((words_read == 2) && (decode_parsebits_is_loopend(words[0]))) {
decode_add_endloop_insn(&pkt->insn[pkt->num_insns++], 0);
}
if (words_read >= 3) {
bool has_loop0, has_loop1;
has_loop0 = decode_parsebits_is_loopend(words[0]);
has_loop1 = decode_parsebits_is_loopend(words[1]);
if (has_loop0 && has_loop1) {
decode_add_endloop_insn(&pkt->insn[pkt->num_insns++], 10);
} else if (has_loop1) {
decode_add_endloop_insn(&pkt->insn[pkt->num_insns++], 1);
} else if (has_loop0) {
decode_add_endloop_insn(&pkt->insn[pkt->num_insns++], 0);
}
}
decode_apply_extenders(pkt);
if (!disas_only) {
decode_remove_extenders(pkt);
}
decode_set_slot_number(pkt);
decode_fill_newvalue_regno(pkt);
if (pkt->pkt_has_hvx) {
mmvec_ext_decode_checks(pkt, disas_only);
}
if (!disas_only) {
decode_shuffle_for_execution(pkt);
decode_split_cmpjump(pkt);
decode_set_insn_attr_fields(pkt);
}
return words_read;
}
/* Used for "-d in_asm" logging */
int disassemble_hexagon(uint32_t *words, int nwords, bfd_vma pc,
GString *buf)
{
Packet pkt;
if (decode_packet(nwords, words, &pkt, true) > 0) {
snprint_a_pkt_disas(buf, &pkt, words, pc);
return pkt.encod_pkt_size_in_bytes;
} else {
g_string_assign(buf, "<invalid>");
return 0;
}
}
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