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target/arm: Implement FIRSTP, LASTP

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Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20260618040718.572950-6-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Richard Henderson
2026-06-17 21:07:15 -07:00
committed by Peter Maydell
parent dab6115d2c
commit e22eb3e0c7
4 changed files with 92 additions and 0 deletions
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3
target/arm/tcg/helper-sve-defs.h
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@@ -961,6 +961,9 @@ DEF_HELPER_FLAGS_4(sve_brkns, TCG_CALL_NO_RWG, i32, ptr, ptr, ptr, i32)
DEF_HELPER_FLAGS_3(sve_cntp, TCG_CALL_NO_RWG, i64, ptr, ptr, i32)
DEF_HELPER_FLAGS_2(sve2p1_cntp_c, TCG_CALL_NO_RWG_SE, i64, i32, i32)
DEF_HELPER_FLAGS_3(sve_firstp, TCG_CALL_NO_RWG_SE, i64, ptr, ptr, i32)
DEF_HELPER_FLAGS_3(sve_lastp, TCG_CALL_NO_RWG_SE, i64, ptr, ptr, i32)
DEF_HELPER_FLAGS_3(sve_whilel, TCG_CALL_NO_RWG, i32, ptr, i32, i32)
DEF_HELPER_FLAGS_3(sve_whileg, TCG_CALL_NO_RWG, i32, ptr, i32, i32)

3
target/arm/tcg/sve.decode
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@@ -852,6 +852,9 @@ BRKN 00100101 0. 01100001 .... 0 .... 0 .... @pd_pg_pn_s
CNTP 00100101 .. 100 000 10 .... 0 .... ..... @rd_pg4_pn
CNTP_c 00100101 esz:2 100 000 10 000 vl:1 1 rn:4 rd:5
FIRSTP 00100101 .. 100 001 10 .... 0 .... ..... @rd_pg4_pn
LASTP 00100101 .. 100 010 10 .... 0 .... ..... @rd_pg4_pn
# SVE inc/dec register by predicate count
INCDECP_r 00100101 .. 10110 d:1 10001 00 .... ..... @incdec_pred u=1

30
target/arm/tcg/sve_helper.c
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@@ -4328,6 +4328,36 @@ uint64_t HELPER(sve2p1_cntp_c)(uint32_t png, uint32_t desc)
return count >> p.lg2_stride;
}
uint64_t HELPER(sve_firstp)(void *vn, void *vg, uint32_t pred_desc)
{
intptr_t words = DIV_ROUND_UP(FIELD_EX32(pred_desc, PREDDESC, OPRSZ), 8);
intptr_t esz = FIELD_EX32(pred_desc, PREDDESC, ESZ);
uint64_t *n = vn, *g = vg, mask = pred_esz_masks[esz];
for (intptr_t i = 0; i < words; ++i) {
uint64_t t = n[i] & g[i] & mask;
if (t) {
return (i * 64 + ctz64(t)) >> esz;
}
}
return -1;
}
uint64_t HELPER(sve_lastp)(void *vn, void *vg, uint32_t pred_desc)
{
intptr_t words = DIV_ROUND_UP(FIELD_EX32(pred_desc, PREDDESC, OPRSZ), 8);
intptr_t esz = FIELD_EX32(pred_desc, PREDDESC, ESZ);
uint64_t *n = vn, *g = vg, mask = pred_esz_masks[esz];
for (intptr_t i = words - 1; i >= 0; --i) {
uint64_t t = n[i] & g[i] & mask;
if (t) {
return (i * 64 + (63 - clz64(t))) >> esz;
}
}
return -1;
}
/* C.f. Arm pseudocode EncodePredCount */
static uint64_t encode_pred_count(uint32_t elements, uint32_t count,
uint32_t esz, bool invert)

56
target/arm/tcg/translate-sve.c
View File

@@ -3481,6 +3481,62 @@ static bool trans_SINCDECP_z(DisasContext *s, arg_incdec2_pred *a)
return true;
}
static bool do_firstp_lastp(DisasContext *s, arg_rpr_esz *a, bool firstp)
{
if (sve_access_check(s)) {
unsigned psz = pred_full_reg_size(s);
TCGv_i64 v = cpu_reg(s, a->rd);
if (psz <= 8) {
uint64_t psz_mask;
tcg_gen_ld_i64(v, tcg_env, pred_full_reg_offset(s, a->rn));
if (a->rn != a->pg) {
TCGv_i64 g = tcg_temp_new_i64();
tcg_gen_ld_i64(g, tcg_env, pred_full_reg_offset(s, a->pg));
tcg_gen_and_i64(v, v, g);
}
/*
* Reduce the pred_esz_masks value simply to reduce the
* size of the code generated here.
*/
psz_mask = MAKE_64BIT_MASK(0, psz * 8);
tcg_gen_andi_i64(v, v, pred_esz_masks[a->esz] & psz_mask);
if (firstp) {
tcg_gen_ctzi_i64(v, v, -1);
} else {
tcg_gen_clzi_i64(v, v, 64);
tcg_gen_subfi_i64(v, 63, v);
}
tcg_gen_sari_i64(v, v, a->esz);
} else {
TCGv_ptr t_pn = tcg_temp_new_ptr();
TCGv_ptr t_pg = tcg_temp_new_ptr();
unsigned desc = 0;
TCGv_i32 t_desc;
desc = FIELD_DP32(desc, PREDDESC, OPRSZ, psz);
desc = FIELD_DP32(desc, PREDDESC, ESZ, a->esz);
tcg_gen_addi_ptr(t_pn, tcg_env, pred_full_reg_offset(s, a->rn));
tcg_gen_addi_ptr(t_pg, tcg_env, pred_full_reg_offset(s, a->pg));
t_desc = tcg_constant_i32(desc);
if (firstp) {
gen_helper_sve_firstp(v, t_pn, t_pg, t_desc);
} else {
gen_helper_sve_lastp(v, t_pn, t_pg, t_desc);
}
}
}
return true;
}
TRANS_FEAT(FIRSTP, aa64_sme2p2_or_sve2p2, do_firstp_lastp, a, true)
TRANS_FEAT(LASTP, aa64_sme2p2_or_sve2p2, do_firstp_lastp, a, false)
/*
*** SVE Integer Compare Scalars Group
*/