From: Paolo Bonzini <pbonzini@redhat.com>
To: Richard Henderson <rth@twiddle.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 11/14] i386: convert gen_compute_eflags_c to TCG
Date: Wed, 10 Oct 2012 08:47:02 +0200 [thread overview]
Message-ID: <507519E6.6020507@redhat.com> (raw)
In-Reply-To: <507483E9.8010908@twiddle.net>
Il 09/10/2012 22:07, Richard Henderson ha scritto:
>> > + case CC_OP_ADCB:
>> > + case CC_OP_ADCW:
>> > + case CC_OP_ADCL:
>> > + case CC_OP_ADCQ:
>> > + /* (DATA_TYPE)CC_DST <= (DATA_TYPE)CC_SRC */
>> > + size = (s->cc_op - CC_OP_ADDB) & 3;
>> > + t1 = gen_ext_tl(cpu_tmp0, cpu_cc_src, size, false);
>> > + t0 = gen_ext_tl(reg, cpu_cc_dst, size, false);
>> > + adc_sbb:
>> > + tcg_gen_setcond_tl(inv ? TCG_COND_GTU : TCG_COND_LEU, reg, t0, t1);
>> > + return;
> There's no point in handling these, because you can never see them
> assigned to s->cc_op. The ADC/SBB translators always set CC_OP_DYNAMIC
> after dynamically selecting CC_OP_ADD or CC_OP_ADC based on the carry-in.
>
That's correct, but compared to
case CC_OP_ADCB:
case CC_OP_ADCW:
case CC_OP_ADCL:
case CC_OP_ADCQ:
case CC_OP_SBBB:
case CC_OP_SBBW:
case CC_OP_SBBL:
case CC_OP_SBBQ:
/* There's no point in handling these, because you can never
* see them assigned to s->cc_op. The ADC/SBB translators
* always set CC_OP_DYNAMIC after dynamically selecting
* CC_OP_ADD or CC_OP_ADC based on the carry-in.
*/
abort();
it's not a great saving and it's a bit less self-documenting...
Paolo
next prev parent reply other threads:[~2012-10-10 6:47 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-06 12:30 [Qemu-devel] [CFT PATCH 00/14] Improve handling of x86 condition codes (tcg) Paolo Bonzini
2012-10-06 12:30 ` [Qemu-devel] [PATCH 01/14] i386: use OT_* consistently Paolo Bonzini
2012-10-07 18:50 ` Blue Swirl
2012-10-09 18:58 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 02/14] i386: introduce gen_ext_tl Paolo Bonzini
2012-10-07 18:53 ` Blue Swirl
2012-10-09 18:58 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 03/14] i386: factor setting of s->cc_op handling for string functions Paolo Bonzini
2012-10-09 18:59 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 04/14] i386: drop cc_op argument of gen_jcc1 Paolo Bonzini
2012-10-09 18:59 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 05/14] i386: move eflags computation closer to gen_op_set_cc_op Paolo Bonzini
2012-10-09 19:02 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 06/14] i386: factor gen_op_set_cc_op/tcg_gen_discard_tl around computing flags Paolo Bonzini
2012-10-09 19:03 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 07/14] i386: add helper functions to get other flags Paolo Bonzini
2012-10-07 19:04 ` Blue Swirl
2012-10-09 19:04 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 08/14] i386: do not compute eflags multiple times consecutively Paolo Bonzini
2012-10-07 19:09 ` Blue Swirl
2012-10-09 19:14 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 09/14] i386: do not call helper to compute ZF/SF Paolo Bonzini
2012-10-07 19:16 ` Blue Swirl
2012-10-09 19:15 ` Richard Henderson
2012-10-09 19:16 ` Richard Henderson
2012-10-10 6:42 ` Paolo Bonzini
2012-10-06 12:30 ` [Qemu-devel] [PATCH 10/14] i386: use inverted setcond when computing NS or NZ Paolo Bonzini
2012-10-07 19:19 ` Blue Swirl
2012-10-09 19:17 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 11/14] i386: convert gen_compute_eflags_c to TCG Paolo Bonzini
2012-10-07 19:35 ` Blue Swirl
2012-10-09 20:07 ` Richard Henderson
2012-10-10 6:47 ` Paolo Bonzini [this message]
2012-10-06 12:30 ` [Qemu-devel] [PATCH 12/14] i386: change gen_setcc_slow_T0 to gen_setcc_slow Paolo Bonzini
2012-10-07 19:36 ` Blue Swirl
2012-10-09 20:07 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 13/14] i386: optimize setbe Paolo Bonzini
2012-10-07 19:43 ` Blue Swirl
2012-10-09 20:13 ` Richard Henderson
2012-10-06 12:30 ` [Qemu-devel] [PATCH 14/14] i386: optimize setcc instructions Paolo Bonzini
2012-10-07 19:58 ` Blue Swirl
2012-10-09 20:22 ` Richard Henderson
2012-10-10 6:51 ` Paolo Bonzini
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