| Message ID | 20211021194547.672988-8-matheus.ferst@eldorado.org.br (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | PowerISA v3.1 instruction batch | expand |
On 10/21/21 12:45 PM, matheus.ferst@eldorado.org.br wrote: > +uint64_t helper_CNTLZDM(uint64_t src, uint64_t mask) > +{ > + uint64_t sel_bit, count = 0; > + > + while (mask != 0) { > + sel_bit = 0x8000000000000000ULL >> clz64(mask); > + > + if (src & sel_bit) { > + break; > + } We need to count how many mask are set left of mask & src. How about sh = clz64(src & mask); if (sh == 0) { return 0; } return ctpop64(mask >> (64 - sh)); which could probably be implemented inline relatively easy. > +static bool trans_CNTLZDM(DisasContext *ctx, arg_X *a) > +{ > + REQUIRE_64BIT(ctx); > + REQUIRE_INSNS_FLAGS2(ctx, ISA310); > +#if defined(TARGET_PPC64) > + gen_helper_CNTLZDM(cpu_gpr[a->ra], cpu_gpr[a->rt], cpu_gpr[a->rb]); > +#else > + qemu_build_not_reached(); > +#endif > + return true; > +} Why the ifdef here? Oh, I see. You could just use target_long in the helper to avoid that. And if not, you should move the helper into an ifdef too. r~
On 22/10/2021 20:16, Richard Henderson wrote: > [E-MAIL EXTERNO] Não clique em links ou abra anexos, a menos que você > possa confirmar o remetente e saber que o conteúdo é seguro. Em caso de > e-mail suspeito entre imediatamente em contato com o DTI. > > On 10/21/21 12:45 PM, matheus.ferst@eldorado.org.br wrote: >> +uint64_t helper_CNTLZDM(uint64_t src, uint64_t mask) >> +{ >> + uint64_t sel_bit, count = 0; >> + >> + while (mask != 0) { >> + sel_bit = 0x8000000000000000ULL >> clz64(mask); >> + >> + if (src & sel_bit) { >> + break; >> + } > > We need to count how many mask are set left of mask & src. > How about > > sh = clz64(src & mask); > if (sh == 0) { > return 0; > } > return ctpop64(mask >> (64 - sh)); > > which could probably be implemented inline relatively easy. > Thanks for this suggestion Richard, we'll try to inline it. >> +static bool trans_CNTLZDM(DisasContext *ctx, arg_X *a) >> +{ >> + REQUIRE_64BIT(ctx); >> + REQUIRE_INSNS_FLAGS2(ctx, ISA310); >> +#if defined(TARGET_PPC64) >> + gen_helper_CNTLZDM(cpu_gpr[a->ra], cpu_gpr[a->rt], cpu_gpr[a->rb]); >> +#else >> + qemu_build_not_reached(); >> +#endif >> + return true; >> +} > > Why the ifdef here? Oh, I see. You could just use target_long in the > helper to avoid > that. And if not, you should move the helper into an ifdef too. > That's the same case of cfuged. There is a vector version of this instruction (vclzdm) that is not 64-bits only (at least on paper), so it should receive i64 and cannot be inside an ifdef(TARGET_PPC64). I'll add this info to the commit message. If we dismiss the possibility of a future 32-bits implementation of PowerISA v3.1, we can move the helper inside the ifdef and add REQUIRE_64BITS in vclzdm/vctzdm (and vcfuged, vpdepd, vpextd, etc.)
diff --git a/target/ppc/helper.h b/target/ppc/helper.h index 6fa3e15fe9..ee7c82fb60 100644 --- a/target/ppc/helper.h +++ b/target/ppc/helper.h @@ -47,6 +47,7 @@ DEF_HELPER_FLAGS_1(popcntb, TCG_CALL_NO_RWG_SE, tl, tl) DEF_HELPER_FLAGS_2(cmpb, TCG_CALL_NO_RWG_SE, tl, tl, tl) DEF_HELPER_3(sraw, tl, env, tl, tl) DEF_HELPER_FLAGS_2(cfuged, TCG_CALL_NO_RWG_SE, i64, i64, i64) +DEF_HELPER_FLAGS_2(CNTLZDM, TCG_CALL_NO_RWG_SE, i64, i64, i64) #if defined(TARGET_PPC64) DEF_HELPER_FLAGS_2(cmpeqb, TCG_CALL_NO_RWG_SE, i32, tl, tl) DEF_HELPER_FLAGS_1(popcntw, TCG_CALL_NO_RWG_SE, tl, tl) diff --git a/target/ppc/insn32.decode b/target/ppc/insn32.decode index 9cb9fc00b8..221cb00dd6 100644 --- a/target/ppc/insn32.decode +++ b/target/ppc/insn32.decode @@ -203,6 +203,7 @@ ADDPCIS 010011 ..... ..... .......... 00010 . @DX ## Fixed-Point Logical Instructions CFUGED 011111 ..... ..... ..... 0011011100 - @X +CNTLZDM 011111 ..... ..... ..... 0000111011 - @X ### Float-Point Load Instructions diff --git a/target/ppc/int_helper.c b/target/ppc/int_helper.c index b3d302390a..dcef356034 100644 --- a/target/ppc/int_helper.c +++ b/target/ppc/int_helper.c @@ -386,6 +386,24 @@ uint64_t helper_cfuged(uint64_t src, uint64_t mask) return left | (right >> n); } +uint64_t helper_CNTLZDM(uint64_t src, uint64_t mask) +{ + uint64_t sel_bit, count = 0; + + while (mask != 0) { + sel_bit = 0x8000000000000000ULL >> clz64(mask); + + if (src & sel_bit) { + break; + } + + count++; + mask &= ~sel_bit; + } + + return count; +} + /*****************************************************************************/ /* PowerPC 601 specific instructions (POWER bridge) */ target_ulong helper_div(CPUPPCState *env, target_ulong arg1, target_ulong arg2) diff --git a/target/ppc/translate/fixedpoint-impl.c.inc b/target/ppc/translate/fixedpoint-impl.c.inc index 0a6b3d61d1..814fef2782 100644 --- a/target/ppc/translate/fixedpoint-impl.c.inc +++ b/target/ppc/translate/fixedpoint-impl.c.inc @@ -415,3 +415,15 @@ static bool trans_CFUGED(DisasContext *ctx, arg_X *a) #endif return true; } + +static bool trans_CNTLZDM(DisasContext *ctx, arg_X *a) +{ + REQUIRE_64BIT(ctx); + REQUIRE_INSNS_FLAGS2(ctx, ISA310); +#if defined(TARGET_PPC64) + gen_helper_CNTLZDM(cpu_gpr[a->ra], cpu_gpr[a->rt], cpu_gpr[a->rb]); +#else + qemu_build_not_reached(); +#endif + return true; +}