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From: "Matheus K. Ferst" <matheus.ferst@eldorado.org.br>
To: Richard Henderson <richard.henderson@linaro.org>, qemu-devel@nongnu.org
Cc: f4bug@amsat.org, luis.pires@eldorado.org.br, qemu-ppc@nongnu.org,
	lagarcia@br.ibm.com, bruno.larsen@eldorado.org.br,
	david@gibson.dropbear.id.au
Subject: Re: [PATCH v3 25/30] target/ppc: Move ADDI, ADDIS to decodetree, implement PADDI
Date: Fri, 30 Apr 2021 15:02:13 -0300	[thread overview]
Message-ID: <34531538-03a7-1fd7-c80b-439a2822e0be@eldorado.org.br> (raw)
In-Reply-To: <b1c975ec-d698-e055-3166-68f8bdf4fbee@linaro.org>

On 30/04/2021 11:31, Richard Henderson wrote:
> On 4/30/21 7:05 AM, Matheus K. Ferst wrote:
>>> +ADDI            000001 10 0--.-- ..................     \
>>> +                001110 ..... ..... ................     @PLS_D
>>
>> I'm not sure about this. It's a bit surprising to find ADDI here, and 
>> the comment that explains why is likely to be ignored after the big 
>> copyright header.
> 
> You could move the comment closer, and replicate, e.g.
> 
> ADDI .... \
>       .... @PLS_D # PADDI
> 
> 

If we keep this naming, IMHO moving the comment closer looks better.

>> I'd prefer to keep a trans_PADDI like
>>
>>  > static bool trans_PADDI(DisasContext *ctx, arg_PLS_D *a)
>>  > {
>>  >     if(!resolve_PLS_D(ctx, a)) {
>>  >         return false;
>>  >     }
>>  >     return trans_ADDI(ctx, a);
>>  > }
> 
> But in this case ADDI probably doesn't use PLS_D.  You could use
> 
> static bool trans_PADDI(DisasContext *ctx, arg_PLS_D *a)
> {
>      arg_D d;
>      if (!resolve_PLS_D(ctx, &d, a)) {
>          return false;
>      }
>      return trans_ADDI(ctx, &d);
> }
> 
> making sure to use int64_t in the offset for arg_D.
> 

We'd keep trans_ADDI with the same signature to avoid creating an arg_D 
on the stack. Patch 4 added type specification, maybe we can define an 
arg_D within arg_PLD_D? I'll play a bit to see if it works.

>> It's the middle way between v2 and v3. trans_ADDI code is reused, 
>> it'll probably be optimized as a tail call, and resolve_PLS_D is not 
>> called when it's not needed.
> 
> My version won't tail-call, because of the escaping local storage, but I 
> don't see how you can avoid it.
> 
> 
> r~

I haven't been able to test it properly yet, but at least on godbolt it 
seems that the compiler prefers to inline over tail call, so maybe 
that's not a problem.

Thanks,
Matheus K. Ferst
Instituto de Pesquisas ELDORADO <http://www.eldorado.org.br/>
Analista de Software Júnior
Aviso Legal - Disclaimer <https://www.eldorado.org.br/disclaimer.html>


  reply	other threads:[~2021-04-30 18:15 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-30  1:15 [PATCH v3 00/30] Base for adding PowerPC 64-bit instructions Richard Henderson
2021-04-30  1:15 ` [PATCH v3 01/30] decodetree: Introduce whex and whexC helpers Richard Henderson
2021-04-30 13:01   ` Luis Fernando Fujita Pires
2021-05-03 22:32   ` Philippe Mathieu-Daudé
2021-04-30  1:15 ` [PATCH v3 02/30] decodetree: More use of f-strings Richard Henderson
2021-04-30 13:01   ` Luis Fernando Fujita Pires
2021-05-03 22:33   ` Philippe Mathieu-Daudé
2021-04-30  1:15 ` [PATCH v3 03/30] decodetree: Add support for 64-bit instructions Richard Henderson
2021-04-30 13:03   ` Luis Fernando Fujita Pires
2021-04-30  1:15 ` [PATCH v3 04/30] decodetree: Extend argument set syntax to allow types Richard Henderson
2021-04-30 13:29   ` Luis Fernando Fujita Pires
2021-04-30  1:15 ` [PATCH v3 05/30] target/ppc: Add cia field to DisasContext Richard Henderson
2021-04-30 20:08   ` Bruno Piazera Larsen
2021-04-30 20:35   ` Luis Fernando Fujita Pires
2021-04-30  1:15 ` [PATCH v3 06/30] target/ppc: Split out decode_legacy Richard Henderson
2021-04-30 20:36   ` Luis Fernando Fujita Pires
2021-04-30  1:15 ` [PATCH v3 07/30] target/ppc: Move DISAS_NORETURN setting into gen_exception* Richard Henderson
2021-05-03 12:58   ` Luis Fernando Fujita Pires
2021-04-30  1:15 ` [PATCH v3 08/30] target/ppc: Remove special case for POWERPC_SYSCALL Richard Henderson
2021-05-03 12:59   ` Luis Fernando Fujita Pires
2021-04-30  1:15 ` [PATCH v3 09/30] target/ppc: Remove special case for POWERPC_EXCP_TRAP Richard Henderson
2021-05-03 13:00   ` Luis Fernando Fujita Pires
2021-04-30  1:15 ` [PATCH v3 10/30] target/ppc: Simplify gen_debug_exception Richard Henderson
2021-04-30  1:15 ` [PATCH v3 11/30] target/ppc: Introduce DISAS_{EXIT,CHAIN}{,_UPDATE} Richard Henderson
2021-04-30  1:15 ` [PATCH v3 12/30] target/ppc: Replace POWERPC_EXCP_SYNC with DISAS_EXIT Richard Henderson
2021-04-30  1:15 ` [PATCH v3 13/30] target/ppc: Remove unnecessary gen_io_end calls Richard Henderson
2021-04-30  1:15 ` [PATCH v3 14/30] target/ppc: Introduce gen_icount_io_start Richard Henderson
2021-04-30  1:15 ` [PATCH v3 15/30] target/ppc: Replace POWERPC_EXCP_STOP with DISAS_EXIT_UPDATE Richard Henderson
2021-04-30  1:15 ` [PATCH v3 16/30] target/ppc: Replace POWERPC_EXCP_BRANCH with DISAS_NORETURN Richard Henderson
2021-04-30  1:15 ` [PATCH v3 17/30] target/ppc: Remove DisasContext.exception Richard Henderson
2021-04-30 13:00   ` Matheus K. Ferst
2021-04-30  1:15 ` [PATCH v3 18/30] target/ppc: Move single-step check to ppc_tr_tb_stop Richard Henderson
2021-04-30  1:15 ` [PATCH v3 19/30] target/ppc: Tidy exception vs exit_tb Richard Henderson
2021-04-30  1:15 ` [PATCH v3 20/30] target/ppc: Mark helper_raise_exception* as noreturn Richard Henderson
2021-05-03 22:36   ` Philippe Mathieu-Daudé
2021-04-30  1:15 ` [PATCH v3 21/30] target/ppc: Use translator_loop_temp_check Richard Henderson
2021-04-30  1:15 ` [PATCH v3 22/30] target/ppc: Introduce macros to check isa extensions Richard Henderson
2021-05-03 22:37   ` Philippe Mathieu-Daudé
2021-04-30  1:15 ` [PATCH v3 23/30] target/ppc: Add infrastructure for prefixed insns Richard Henderson
2021-04-30  1:15 ` [PATCH v3 24/30] target/ppc: Move page crossing check to ppc_tr_translate_insn Richard Henderson
2021-04-30  1:26   ` Richard Henderson
2021-04-30  1:15 ` [PATCH v3 25/30] target/ppc: Move ADDI, ADDIS to decodetree, implement PADDI Richard Henderson
2021-04-30 11:23   ` Luis Fernando Fujita Pires
2021-04-30 14:23     ` Richard Henderson
2021-04-30 18:45       ` Luis Fernando Fujita Pires
2021-04-30 19:11         ` Richard Henderson
2021-04-30 20:32           ` Luis Fernando Fujita Pires
2021-04-30 22:29             ` Richard Henderson
2021-04-30 14:05   ` Matheus K. Ferst
2021-04-30 14:31     ` Richard Henderson
2021-04-30 18:02       ` Matheus K. Ferst [this message]
2021-04-30 18:43         ` Richard Henderson
2021-04-30 23:29           ` Matheus K. Ferst
2021-04-30  1:15 ` [PATCH v3 26/30] target/ppc: Implement PNOP Richard Henderson
2021-05-03 22:41   ` Philippe Mathieu-Daudé
2021-04-30  1:15 ` [PATCH v3 27/30] target/ppc: Move D/DS/X-form integer loads to decodetree Richard Henderson
2021-04-30 23:54   ` Matheus K. Ferst
2021-05-01  0:50     ` Richard Henderson
2021-05-03 12:28       ` Matheus K. Ferst
2021-04-30  1:15 ` [PATCH v3 28/30] target/ppc: Implement prefixed integer load instructions Richard Henderson
2021-04-30  1:15 ` [PATCH v3 29/30] target/ppc: Move D/DS/X-form integer stores to decodetree Richard Henderson
2021-04-30  1:15 ` [PATCH v3 30/30] target/ppc: Implement prefixed integer store instructions Richard Henderson
2021-04-30  1:48 ` [PATCH v3 00/30] Base for adding PowerPC 64-bit instructions no-reply

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