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/*
* ARM translation: M-profile NOCP special-case instructions
*
* Copyright (c) 2020 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 "tcg/tcg-op.h"
#include "translate.h"
#include "translate-a32.h"
#include "decode-m-nocp.c.inc"
/*
* Decode VLLDM and VLSTM are nonstandard because:
* * if there is no FPU then these insns must NOP in
* Secure state and UNDEF in Nonsecure state
* * if there is an FPU then these insns do not have
* the usual behaviour that vfp_access_check() provides of
* being controlled by CPACR/NSACR enable bits or the
* lazy-stacking logic.
*/
static bool trans_VLLDM_VLSTM(DisasContext *s, arg_VLLDM_VLSTM *a)
{
TCGv_i32 fptr;
if (!arm_dc_feature(s, ARM_FEATURE_M) ||
!arm_dc_feature(s, ARM_FEATURE_V8)) {
return false;
}
if (a->op) {
/*
* T2 encoding ({D0-D31} reglist): v8.1M and up. We choose not
* to take the IMPDEF option to make memory accesses to the stack
* slots that correspond to the D16-D31 registers (discarding
* read data and writing UNKNOWN values), so for us the T2
* encoding behaves identically to the T1 encoding.
*/
if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
return false;
}
} else {
/*
* T1 encoding ({D0-D15} reglist); undef if we have 32 Dregs.
* This is currently architecturally impossible, but we add the
* check to stay in line with the pseudocode. Note that we must
* emit code for the UNDEF so it takes precedence over the NOCP.
*/
if (dc_isar_feature(aa32_simd_r32, s)) {
unallocated_encoding(s);
return true;
}
}
/*
* If not secure, UNDEF. We must emit code for this
* rather than returning false so that this takes
* precedence over the m-nocp.decode NOCP fallback.
*/
if (!s->v8m_secure) {
unallocated_encoding(s);
return true;
}
/* If no fpu, NOP. */
if (!dc_isar_feature(aa32_vfp, s)) {
return true;
}
fptr = load_reg(s, a->rn);
if (a->l) {
gen_helper_v7m_vlldm(cpu_env, fptr);
} else {
gen_helper_v7m_vlstm(cpu_env, fptr);
}
tcg_temp_free_i32(fptr);
/* End the TB, because we have updated FP control bits */
s->base.is_jmp = DISAS_UPDATE_EXIT;
return true;
}
static bool trans_VSCCLRM(DisasContext *s, arg_VSCCLRM *a)
{
int btmreg, topreg;
TCGv_i64 zero;
TCGv_i32 aspen, sfpa;
if (!dc_isar_feature(aa32_m_sec_state, s)) {
/* Before v8.1M, fall through in decode to NOCP check */
return false;
}
/* Explicitly UNDEF because this takes precedence over NOCP */
if (!arm_dc_feature(s, ARM_FEATURE_M_MAIN) || !s->v8m_secure) {
unallocated_encoding(s);
return true;
}
if (!dc_isar_feature(aa32_vfp_simd, s)) {
/* NOP if we have neither FP nor MVE */
return true;
}
/*
* If FPCCR.ASPEN != 0 && CONTROL_S.SFPA == 0 then there is no
* active floating point context so we must NOP (without doing
* any lazy state preservation or the NOCP check).
*/
aspen = load_cpu_field(v7m.fpccr[M_REG_S]);
sfpa = load_cpu_field(v7m.control[M_REG_S]);
tcg_gen_andi_i32(aspen, aspen, R_V7M_FPCCR_ASPEN_MASK);
tcg_gen_xori_i32(aspen, aspen, R_V7M_FPCCR_ASPEN_MASK);
tcg_gen_andi_i32(sfpa, sfpa, R_V7M_CONTROL_SFPA_MASK);
tcg_gen_or_i32(sfpa, sfpa, aspen);
arm_gen_condlabel(s);
tcg_gen_brcondi_i32(TCG_COND_EQ, sfpa, 0, s->condlabel);
if (s->fp_excp_el != 0) {
gen_exception_insn(s, s->pc_curr, EXCP_NOCP,
syn_uncategorized(), s->fp_excp_el);
return true;
}
topreg = a->vd + a->imm - 1;
btmreg = a->vd;
/* Convert to Sreg numbers if the insn specified in Dregs */
if (a->size == 3) {
topreg = topreg * 2 + 1;
btmreg *= 2;
}
if (topreg > 63 || (topreg > 31 && !(topreg & 1))) {
/* UNPREDICTABLE: we choose to undef */
unallocated_encoding(s);
return true;
}
/* Silently ignore requests to clear D16-D31 if they don't exist */
if (topreg > 31 && !dc_isar_feature(aa32_simd_r32, s)) {
topreg = 31;
}
if (!vfp_access_check(s)) {
return true;
}
/* Zero the Sregs from btmreg to topreg inclusive. */
zero = tcg_const_i64(0);
if (btmreg & 1) {
write_neon_element64(zero, btmreg >> 1, 1, MO_32);
btmreg++;
}
for (; btmreg + 1 <= topreg; btmreg += 2) {
write_neon_element64(zero, btmreg >> 1, 0, MO_64);
}
if (btmreg == topreg) {
write_neon_element64(zero, btmreg >> 1, 0, MO_32);
btmreg++;
}
assert(btmreg == topreg + 1);
/* TODO: when MVE is implemented, zero VPR here */
return true;
}
static bool trans_NOCP(DisasContext *s, arg_nocp *a)
{
/*
* Handle M-profile early check for disabled coprocessor:
* all we need to do here is emit the NOCP exception if
* the coprocessor is disabled. Otherwise we return false
* and the real VFP/etc decode will handle the insn.
*/
assert(arm_dc_feature(s, ARM_FEATURE_M));
if (a->cp == 11) {
a->cp = 10;
}
if (arm_dc_feature(s, ARM_FEATURE_V8_1M) &&
(a->cp == 8 || a->cp == 9 || a->cp == 14 || a->cp == 15)) {
/* in v8.1M cp 8, 9, 14, 15 also are governed by the cp10 enable */
a->cp = 10;
}
if (a->cp != 10) {
gen_exception_insn(s, s->pc_curr, EXCP_NOCP,
syn_uncategorized(), default_exception_el(s));
return true;
}
if (s->fp_excp_el != 0) {
gen_exception_insn(s, s->pc_curr, EXCP_NOCP,
syn_uncategorized(), s->fp_excp_el);
return true;
}
return false;
}
static bool trans_NOCP_8_1(DisasContext *s, arg_nocp *a)
{
/* This range needs a coprocessor check for v8.1M and later only */
if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
return false;
}
return trans_NOCP(s, a);
}
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