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From: =?utf-8?Q?Llu=C3=ADs_Vilanova?= <vilanova@ac.upc.edu>
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	<01ac89ab-c7b0-3ada-b8bf-9f033cf90f15@twiddle.net>
Date: Sat, 15 Jul 2017 10:34:20 +0300
In-Reply-To: <01ac89ab-c7b0-3ada-b8bf-9f033cf90f15@twiddle.net> (Richard
	Henderson's message of "Fri, 14 Jul 2017 06:48:02 -1000")
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Subject: Re: [Qemu-devel] [PATCH v13 03/26] target: [tcg] Add generic
 translation framework
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To: Richard Henderson <rth@twiddle.net>
Cc: qemu-devel@nongnu.org, "Emilio G. Cota" <cota@braap.org>, Alex =?utf-8?Q?Benn=C3=A9e?= <alex.bennee@linaro.org>, Peter Crosthwaite <crosthwaite.peter@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>

Richard Henderson writes:

> On 07/13/2017 10:25 PM, Llu=C3=ADs Vilanova wrote:
>> +        /* Pass breakpoint hits to target for further processing */
>> +        if (unlikely(!QTAILQ_EMPTY(&cpu->breakpoints))) {
>> +            CPUBreakpoint *bp;
>> +            QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) {
>> +                if (bp->pc =3D=3D db->pc_next) {
>> +                    if (ops->breakpoint_check(db, cpu, bp)) {
>> +                        break;
>> +                    }
>> +                }
>> +            }
>> +
>> +            if (db->is_jmp =3D=3D DISAS_NORETURN) {
>> +                break;
>> +            }
>> +        }

> You should accept any !=3D DISAS_NEXT value here.
> (1) Because DISAS_NEXT =3D=3D 0 and it's the quickest test, and
> (2) If you *require* NORETURN here, then you've also got to
> convert some of the backends to not use DISAS_TARGET_N, which
> as of [07/26] target/i386: [tcg] Port to breakpoint_check, I
> haven't seen happen.

No, arm has cases with both DISAS_TARGET_N and DISAS_NORETURN, where both e=
nd
the bp check loop, but only DISAS_NORETURN breaks the translation loop (the
previous goto done_generating).

And i386 has no DISAS_NORETURN simply because that's not the behaviour in i=
ts
original code.