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target/ppc: Use gvec to decode XVTSTDC[DS]P
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Used gvec to translate XVTSTDCSP and XVTSTDCDP.

xvtstdcsp:
rept    loop    imm     master version  prev version        current version
25      4000    0       0,206200        0,040730 (-80.2%)    0,040740 (-80.2%)
25      4000    1       0,205120        0,053650 (-73.8%)    0,053510 (-73.9%)
25      4000    3       0,206160        0,058630 (-71.6%)    0,058570 (-71.6%)
25      4000    51      0,217110        0,191490 (-11.8%)    0,192320 (-11.4%)
25      4000    127     0,206160        0,191490 (-7.1%)     0,192640 (-6.6%)
8000    12      0       1,234719        0,418833 (-66.1%)    0,386365 (-68.7%)
8000    12      1       1,232417        1,435979 (+16.5%)    1,462792 (+18.7%)
8000    12      3       1,232760        1,766073 (+43.3%)    1,743990 (+41.5%)
8000    12      51      1,239281        1,319562 (+6.5%)     1,423479 (+14.9%)
8000    12      127     1,231708        1,315760 (+6.8%)     1,426667 (+15.8%)

xvtstdcdp:
rept    loop    imm     master version  prev version    current version
25      4000    0       0,159930        0,040830 (-74.5%)    0,040610 (-74.6%)
25      4000    1       0,160640        0,053670 (-66.6%)    0,053480 (-66.7%)
25      4000    3       0,160020        0,063030 (-60.6%)    0,062960 (-60.7%)
25      4000    51      0,160410        0,128620 (-19.8%)    0,127470 (-20.5%)
25      4000    127     0,160330        0,127670 (-20.4%)    0,128690 (-19.7%)
8000    12      0       1,190365        0,422146 (-64.5%)    0,388417 (-67.4%)
8000    12      1       1,191292        1,445312 (+21.3%)    1,428698 (+19.9%)
8000    12      3       1,188687        1,980656 (+66.6%)    1,975354 (+66.2%)
8000    12      51      1,191250        1,264500 (+6.1%)     1,355083 (+13.8%)
8000    12      127     1,197313        1,266729 (+5.8%)     1,349156 (+12.7%)

Overall, these instructions are the hardest ones to measure performance
as the gvec implementation is affected by the immediate. Above there are
5 different scenarios when it comes to immediate and 2 when it comes to
rept/loop combination. The immediates scenarios are: all bits are 0
therefore the target register should just be changed to 0, with 1 bit
set, with 2 bits set in a combination the new implementation can deal
with using gvec, 4 bits set and the new implementation can't deal with
it using gvec and all bits set. The rept/loop scenarios are high loop
and low rept (so it should spend more time executing it than translating
it) and high rept low loop (so it should spend more time translating it
than executing this code).
These comparisons are between the upstream version, a previous similar
implementation and a one with a cleaner code(this one).
For a comparison with o previous different implementation:
<20221010191356.83659-13-lucas.araujo@eldorado.org.br>

Signed-off-by: Lucas Mateus Castro (alqotel) <lucas.araujo@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20221019125040.48028-13-lucas.araujo@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
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@danielhb
Lucas Mateus Castro (alqotel) authored and danielhb committed Oct 28, 2022
1 parent da3c53b commit bbd8dd5
Showing 1 changed file with 157 additions and 10 deletions.
167 changes: 157 additions & 10 deletions target/ppc/translate/vsx-impl.c.inc
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Expand Up @@ -632,6 +632,8 @@ static void gen_mtvsrws(DisasContext *ctx)
#define SGN_MASK_SP 0x8000000080000000ull
#define EXP_MASK_DP 0x7FF0000000000000ull
#define EXP_MASK_SP 0x7F8000007F800000ull
#define FRC_MASK_DP (~(SGN_MASK_DP | EXP_MASK_DP))
#define FRC_MASK_SP (~(SGN_MASK_SP | EXP_MASK_SP))

#define VSX_SCALAR_MOVE(name, op, sgn_mask) \
static void glue(gen_, name)(DisasContext *ctx) \
Expand Down Expand Up @@ -1112,23 +1114,168 @@ GEN_VSX_HELPER_X2(xscvhpdp, 0x16, 0x15, 0x10, PPC2_ISA300)
GEN_VSX_HELPER_R2(xscvsdqp, 0x04, 0x1A, 0x0A, PPC2_ISA300)
GEN_VSX_HELPER_X2(xscvspdp, 0x12, 0x14, 0, PPC2_VSX)

/* test if +Inf */
static void gen_is_pos_inf(unsigned vece, TCGv_vec t, TCGv_vec b, int64_t v)
{
uint64_t exp_msk = (vece == MO_32) ? (uint32_t)EXP_MASK_SP : EXP_MASK_DP;
tcg_gen_cmp_vec(TCG_COND_EQ, vece, t, b,
tcg_constant_vec_matching(t, vece, exp_msk));
}

/* test if -Inf */
static void gen_is_neg_inf(unsigned vece, TCGv_vec t, TCGv_vec b, int64_t v)
{
uint64_t exp_msk = (vece == MO_32) ? (uint32_t)EXP_MASK_SP : EXP_MASK_DP;
uint64_t sgn_msk = (vece == MO_32) ? (uint32_t)SGN_MASK_SP : SGN_MASK_DP;
tcg_gen_cmp_vec(TCG_COND_EQ, vece, t, b,
tcg_constant_vec_matching(t, vece, sgn_msk | exp_msk));
}

/* test if +Inf or -Inf */
static void gen_is_any_inf(unsigned vece, TCGv_vec t, TCGv_vec b, int64_t v)
{
uint64_t exp_msk = (vece == MO_32) ? (uint32_t)EXP_MASK_SP : EXP_MASK_DP;
uint64_t sgn_msk = (vece == MO_32) ? (uint32_t)SGN_MASK_SP : SGN_MASK_DP;
tcg_gen_andc_vec(vece, b, b, tcg_constant_vec_matching(t, vece, sgn_msk));
tcg_gen_cmp_vec(TCG_COND_EQ, vece, t, b,
tcg_constant_vec_matching(t, vece, exp_msk));
}

/* test if +0 */
static void gen_is_pos_zero(unsigned vece, TCGv_vec t, TCGv_vec b, int64_t v)
{
tcg_gen_cmp_vec(TCG_COND_EQ, vece, t, b,
tcg_constant_vec_matching(t, vece, 0));
}

/* test if -0 */
static void gen_is_neg_zero(unsigned vece, TCGv_vec t, TCGv_vec b, int64_t v)
{
uint64_t sgn_msk = (vece == MO_32) ? (uint32_t)SGN_MASK_SP : SGN_MASK_DP;
tcg_gen_cmp_vec(TCG_COND_EQ, vece, t, b,
tcg_constant_vec_matching(t, vece, sgn_msk));
}

/* test if +0 or -0 */
static void gen_is_any_zero(unsigned vece, TCGv_vec t, TCGv_vec b, int64_t v)
{
uint64_t sgn_msk = (vece == MO_32) ? (uint32_t)SGN_MASK_SP : SGN_MASK_DP;
tcg_gen_andc_vec(vece, b, b, tcg_constant_vec_matching(t, vece, sgn_msk));
tcg_gen_cmp_vec(TCG_COND_EQ, vece, t, b,
tcg_constant_vec_matching(t, vece, 0));
}

/* test if +Denormal */
static void gen_is_pos_denormal(unsigned vece, TCGv_vec t,
TCGv_vec b, int64_t v)
{
uint64_t frc_msk = (vece == MO_32) ? (uint32_t)FRC_MASK_SP : FRC_MASK_DP;
tcg_gen_cmp_vec(TCG_COND_LEU, vece, t, b,
tcg_constant_vec_matching(t, vece, frc_msk));
tcg_gen_cmp_vec(TCG_COND_NE, vece, b, b,
tcg_constant_vec_matching(t, vece, 0));
tcg_gen_and_vec(vece, t, t, b);
}

/* test if -Denormal */
static void gen_is_neg_denormal(unsigned vece, TCGv_vec t,
TCGv_vec b, int64_t v)
{
uint64_t sgn_msk = (vece == MO_32) ? (uint32_t)SGN_MASK_SP : SGN_MASK_DP;
uint64_t frc_msk = (vece == MO_32) ? (uint32_t)FRC_MASK_SP : FRC_MASK_DP;
tcg_gen_cmp_vec(TCG_COND_LEU, vece, t, b,
tcg_constant_vec_matching(t, vece, sgn_msk | frc_msk));
tcg_gen_cmp_vec(TCG_COND_GTU, vece, b, b,
tcg_constant_vec_matching(t, vece, sgn_msk));
tcg_gen_and_vec(vece, t, t, b);
}

/* test if +Denormal or -Denormal */
static void gen_is_any_denormal(unsigned vece, TCGv_vec t,
TCGv_vec b, int64_t v)
{
uint64_t sgn_msk = (vece == MO_32) ? (uint32_t)SGN_MASK_SP : SGN_MASK_DP;
uint64_t frc_msk = (vece == MO_32) ? (uint32_t)FRC_MASK_SP : FRC_MASK_DP;
tcg_gen_andc_vec(vece, b, b, tcg_constant_vec_matching(t, vece, sgn_msk));
tcg_gen_cmp_vec(TCG_COND_LE, vece, t, b,
tcg_constant_vec_matching(t, vece, frc_msk));
tcg_gen_cmp_vec(TCG_COND_NE, vece, b, b,
tcg_constant_vec_matching(t, vece, 0));
tcg_gen_and_vec(vece, t, t, b);
}

/* test if NaN */
static void gen_is_nan(unsigned vece, TCGv_vec t, TCGv_vec b, int64_t v)
{
uint64_t exp_msk = (vece == MO_32) ? (uint32_t)EXP_MASK_SP : EXP_MASK_DP;
uint64_t sgn_msk = (vece == MO_32) ? (uint32_t)SGN_MASK_SP : SGN_MASK_DP;
tcg_gen_and_vec(vece, b, b, tcg_constant_vec_matching(t, vece, ~sgn_msk));
tcg_gen_cmp_vec(TCG_COND_GT, vece, t, b,
tcg_constant_vec_matching(t, vece, exp_msk));
}

static bool do_xvtstdc(DisasContext *ctx, arg_XX2_uim *a, unsigned vece)
{
static const GVecGen2i op[] = {
{
.fnoi = gen_helper_XVTSTDCSP,
.vece = MO_32
},
{
.fnoi = gen_helper_XVTSTDCDP,
.vece = MO_64
},
static const TCGOpcode vecop_list[] = {
INDEX_op_cmp_vec, 0
};

GVecGen2i op = {
.fnoi = (vece == MO_32) ? gen_helper_XVTSTDCSP : gen_helper_XVTSTDCDP,
.vece = vece,
.opt_opc = vecop_list
};

REQUIRE_VSX(ctx);

switch (a->uim) {
case 0:
set_cpu_vsr(a->xt, tcg_constant_i64(0), true);
set_cpu_vsr(a->xt, tcg_constant_i64(0), false);
return true;
case ((1 << 0) | (1 << 1)):
/* test if +Denormal or -Denormal */
op.fniv = gen_is_any_denormal;
break;
case (1 << 0):
/* test if -Denormal */
op.fniv = gen_is_neg_denormal;
break;
case (1 << 1):
/* test if +Denormal */
op.fniv = gen_is_pos_denormal;
break;
case ((1 << 2) | (1 << 3)):
/* test if +0 or -0 */
op.fniv = gen_is_any_zero;
break;
case (1 << 2):
/* test if -0 */
op.fniv = gen_is_neg_zero;
break;
case (1 << 3):
/* test if +0 */
op.fniv = gen_is_pos_zero;
break;
case ((1 << 4) | (1 << 5)):
/* test if +Inf or -Inf */
op.fniv = gen_is_any_inf;
break;
case (1 << 4):
/* test if -Inf */
op.fniv = gen_is_neg_inf;
break;
case (1 << 5):
/* test if +Inf */
op.fniv = gen_is_pos_inf;
break;
case (1 << 6):
/* test if NaN */
op.fniv = gen_is_nan;
break;
}
tcg_gen_gvec_2i(vsr_full_offset(a->xt), vsr_full_offset(a->xb),
16, 16, (int32_t)(a->uim), &op[vece - MO_32]);
16, 16, a->uim, &op);

return true;
}
Expand Down

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