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Re: [Qemu-devel] [PATCH 14/28] m68k: replace cpu_m68k_init() with cpu_ge
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH 14/28] m68k: replace cpu_m68k_init() with cpu_generic_init() |
Date: |
Mon, 14 Aug 2017 10:00:36 +0200 |
On Mon, 17 Jul 2017 17:23:22 +0200
Igor Mammedov <address@hidden> wrote:
> On Mon, 17 Jul 2017 17:05:15 +0200
> Andreas Färber <address@hidden> wrote:
>
> > Am 17.07.2017 um 12:41 schrieb Igor Mammedov:
> > > On Sat, 15 Jul 2017 08:08:58 -1000
> > > Richard Henderson <address@hidden> wrote:
> > >
> > >> On 07/14/2017 03:52 AM, Igor Mammedov wrote:
> > >>> @@ -230,6 +230,8 @@ static void m68k_cpu_realizefn(DeviceState *dev,
> > >>> Error **errp)
> > >>> M68kCPUClass *mcc = M68K_CPU_GET_CLASS(dev);
> > >>> Error *local_err = NULL;
> > >>>
> > >>> + register_m68k_insns(&cpu->env);
> > >>> +
> > >>
> > >> I think it would make more sense to do this during m68k_tcg_init.
> > >>
> > > it seems that m68k_cpu_initfn accesses 'env' via some global,
> > > while cpu_mk68k_init() used to access concrete pointer of just created
> > > cpu,
> > >
> > > how about moving register_m68k_insns() to m68k_cpu_initfn(), instead?
> > > it should be equivalent to what cpu_mk68k_init() used to do.
> >
> > As a general note, realize should be re-entrant. Can't tell from the
> > above diff whether that is the case here.
> Looking at
>
> void register_m68k_insns (CPUM68KState *env)
>
> {
>
> /* Build the opcode table only once to avoid
>
> multithreading issues. */
>
> if (opcode_table[0] != NULL) {
>
> return;
>
> }
>
> it is save to use multiple times,
>
> also looking further in it:
>
> #define BASE(name, opcode, mask) \
>
> register_opcode(disas_##name, 0x##opcode, 0x##mask)
>
> #define INSN(name, opcode, mask, feature) do { \
>
> if (m68k_feature(env, M68K_FEATURE_##feature)) \
>
> BASE(name, opcode, mask); \
>
> } while(0)
>
> BASE(undef, 0000, 0000);
>
> INSN(arith_im, 0080, fff8, CF_ISA_A);
>
> INSN macro depends on enabled features, it might work with current code that
> has no user settable features but it will break once that is available.
>
> So I retract my suggestion to move register_m68k_insns() into
> m68k_cpu_initfn()
> and keep it as it's in this patch (in m68k_cpu_realizefn()),
> that way features theoretically set between initfn(and m68k_tcg_init) and
> realize() will
> have effect on created cpu and we won't have to fix it in future.
Richard, Laurent,
Do you agree with keeping register_m68k_insns() in realize()?
- Re: [Qemu-devel] [PATCH 14/28] m68k: replace cpu_m68k_init() with cpu_generic_init(),
Igor Mammedov <=