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target/arm: Convert Neon one-register-and-immediate insns to decodetree

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Convert the insns in the one-register-and-immediate group to decodetree.

In the new decode, our asimd_imm_const() function returns a 64-bit value
rather than a 32-bit one, which means we don't need to treat cmode=14 op=1
as a special case in the decoder (it is the only encoding where the two
halves of the 64-bit value are different).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200522145520.6778-10-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2020-05-22 15:55:20 +01:00
parent 3da26f1171
commit 2c35a39eda
3 changed files with 142 additions and 99 deletions
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22
target/arm/neon-dp.decode
View File

@ -375,3 +375,25 @@ VCVT_SF_2sh 1111 001 0 1 . ...... .... 1110 0 . . 1 .... @2reg_vcvt
VCVT_UF_2sh 1111 001 1 1 . ...... .... 1110 0 . . 1 .... @2reg_vcvt
VCVT_FS_2sh 1111 001 0 1 . ...... .... 1111 0 . . 1 .... @2reg_vcvt
VCVT_FU_2sh 1111 001 1 1 . ...... .... 1111 0 . . 1 .... @2reg_vcvt
######################################################################
# 1-reg-and-modified-immediate grouping:
# 1111 001 i 1 D 000 imm:3 Vd:4 cmode:4 0 Q op 1 Vm:4
######################################################################
&1reg_imm vd q imm cmode op
%asimd_imm_value 24:1 16:3 0:4
@1reg_imm .... ... . . . ... ... .... .... . q:1 . . .... \
&1reg_imm imm=%asimd_imm_value vd=%vd_dp
# The cmode/op bits here decode VORR/VBIC/VMOV/VMNV, but
# not in a way we can conveniently represent in decodetree without
# a lot of repetition:
# VORR: op=0, (cmode & 1) && cmode < 12
# VBIC: op=1, (cmode & 1) && cmode < 12
# VMOV: everything else
# So we have a single decode line and check the cmode/op in the
# trans function.
Vimm_1r 1111 001 . 1 . 000 ... .... cmode:4 0 . op:1 1 .... @1reg_imm

118
target/arm/translate-neon.inc.c
View File

@ -1708,3 +1708,121 @@ DO_FP_2SH(VCVT_SF, gen_helper_vfp_sltos)
DO_FP_2SH(VCVT_UF, gen_helper_vfp_ultos)
DO_FP_2SH(VCVT_FS, gen_helper_vfp_tosls_round_to_zero)
DO_FP_2SH(VCVT_FU, gen_helper_vfp_touls_round_to_zero)
static uint64_t asimd_imm_const(uint32_t imm, int cmode, int op)
{
/*
* Expand the encoded constant.
* Note that cmode = 2,3,4,5,6,7,10,11,12,13 imm=0 is UNPREDICTABLE.
* We choose to not special-case this and will behave as if a
* valid constant encoding of 0 had been given.
* cmode = 15 op = 1 must UNDEF; we assume decode has handled that.
*/
switch (cmode) {
case 0: case 1:
/* no-op */
break;
case 2: case 3:
imm <<= 8;
break;
case 4: case 5:
imm <<= 16;
break;
case 6: case 7:
imm <<= 24;
break;
case 8: case 9:
imm |= imm << 16;
break;
case 10: case 11:
imm = (imm << 8) | (imm << 24);
break;
case 12:
imm = (imm << 8) | 0xff;
break;
case 13:
imm = (imm << 16) | 0xffff;
break;
case 14:
if (op) {
/*
* This is the only case where the top and bottom 32 bits
* of the encoded constant differ.
*/
uint64_t imm64 = 0;
int n;
for (n = 0; n < 8; n++) {
if (imm & (1 << n)) {
imm64 |= (0xffULL << (n * 8));
}
}
return imm64;
}
imm |= (imm << 8) | (imm << 16) | (imm << 24);
break;
case 15:
imm = ((imm & 0x80) << 24) | ((imm & 0x3f) << 19)
| ((imm & 0x40) ? (0x1f << 25) : (1 << 30));
break;
}
if (op) {
imm = ~imm;
}
return dup_const(MO_32, imm);
}
static bool do_1reg_imm(DisasContext *s, arg_1reg_imm *a,
GVecGen2iFn *fn)
{
uint64_t imm;
int reg_ofs, vec_size;
if (!arm_dc_feature(s, ARM_FEATURE_NEON)) {
return false;
}
/* UNDEF accesses to D16-D31 if they don't exist. */
if (!dc_isar_feature(aa32_simd_r32, s) && (a->vd & 0x10)) {
return false;
}
if (a->vd & a->q) {
return false;
}
if (!vfp_access_check(s)) {
return true;
}
reg_ofs = neon_reg_offset(a->vd, 0);
vec_size = a->q ? 16 : 8;
imm = asimd_imm_const(a->imm, a->cmode, a->op);
fn(MO_64, reg_ofs, reg_ofs, imm, vec_size, vec_size);
return true;
}
static void gen_VMOV_1r(unsigned vece, uint32_t dofs, uint32_t aofs,
int64_t c, uint32_t oprsz, uint32_t maxsz)
{
tcg_gen_gvec_dup_imm(MO_64, dofs, oprsz, maxsz, c);
}
static bool trans_Vimm_1r(DisasContext *s, arg_1reg_imm *a)
{
/* Handle decode of cmode/op here between VORR/VBIC/VMOV */
GVecGen2iFn *fn;
if ((a->cmode & 1) && a->cmode < 12) {
/* for op=1, the imm will be inverted, so BIC becomes AND. */
fn = a->op ? tcg_gen_gvec_andi : tcg_gen_gvec_ori;
} else {
/* There is one unallocated cmode/op combination in this space */
if (a->cmode == 15 && a->op == 1) {
return false;
}
fn = gen_VMOV_1r;
}
return do_1reg_imm(s, a, fn);
}

101
target/arm/translate.c
View File

@ -5232,105 +5232,8 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
/* Three register same length: handled by decodetree */
return 1;
} else if (insn & (1 << 4)) {
if ((insn & 0x00380080) != 0) {
/* Two registers and shift: handled by decodetree */
return 1;
} else { /* (insn & 0x00380080) == 0 */
int invert, reg_ofs, vec_size;
if (q && (rd & 1)) {
return 1;
}
op = (insn >> 8) & 0xf;
/* One register and immediate. */
imm = (u << 7) | ((insn >> 12) & 0x70) | (insn & 0xf);
invert = (insn & (1 << 5)) != 0;
/* Note that op = 2,3,4,5,6,7,10,11,12,13 imm=0 is UNPREDICTABLE.
* We choose to not special-case this and will behave as if a
* valid constant encoding of 0 had been given.
*/
switch (op) {
case 0: case 1:
/* no-op */
break;
case 2: case 3:
imm <<= 8;
break;
case 4: case 5:
imm <<= 16;
break;
case 6: case 7:
imm <<= 24;
break;
case 8: case 9:
imm |= imm << 16;
break;
case 10: case 11:
imm = (imm << 8) | (imm << 24);
break;
case 12:
imm = (imm << 8) | 0xff;
break;
case 13:
imm = (imm << 16) | 0xffff;
break;
case 14:
imm |= (imm << 8) | (imm << 16) | (imm << 24);
if (invert) {
imm = ~imm;
}
break;
case 15:
if (invert) {
return 1;
}
imm = ((imm & 0x80) << 24) | ((imm & 0x3f) << 19)
| ((imm & 0x40) ? (0x1f << 25) : (1 << 30));
break;
}
if (invert) {
imm = ~imm;
}
reg_ofs = neon_reg_offset(rd, 0);
vec_size = q ? 16 : 8;
if (op & 1 && op < 12) {
if (invert) {
/* The immediate value has already been inverted,
* so BIC becomes AND.
*/
tcg_gen_gvec_andi(MO_32, reg_ofs, reg_ofs, imm,
vec_size, vec_size);
} else {
tcg_gen_gvec_ori(MO_32, reg_ofs, reg_ofs, imm,
vec_size, vec_size);
}
} else {
/* VMOV, VMVN. */
if (op == 14 && invert) {
TCGv_i64 t64 = tcg_temp_new_i64();
for (pass = 0; pass <= q; ++pass) {
uint64_t val = 0;
int n;
for (n = 0; n < 8; n++) {
if (imm & (1 << (n + pass * 8))) {
val |= 0xffull << (n * 8);
}
}
tcg_gen_movi_i64(t64, val);
neon_store_reg64(t64, rd + pass);
}
tcg_temp_free_i64(t64);
} else {
tcg_gen_gvec_dup_imm(MO_32, reg_ofs, vec_size,
vec_size, imm);
}
}
}
/* Two registers and shift or reg and imm: handled by decodetree */
return 1;
} else { /* (insn & 0x00800010 == 0x00800000) */
if (size != 3) {
op = (insn >> 8) & 0xf;