Re: [Qemu-devel] [PATCH for-2.5 08/30] m68k: update CPU flags management

[Richard Henderson <rth@twiddle.net>]

On 08/09/2015 01:13 PM, Laurent Vivier wrote:
> @@ -798,9 +796,9 @@ void HELPER(mac_set_flags)(CPUM68KState *env, uint32_t acc)
>       }
>   }
>
> -void HELPER(flush_flags)(CPUM68KState *env, uint32_t cc_op)
> +uint32_t HELPER(flush_flags)(CPUM68KState *env, uint32_t op)
>   {
> -    cpu_m68k_flush_flags(env, cc_op);
> +    return cpu_m68k_flush_flags(env, op);
>   }

Since this function no longer modifies ENV, it probably deserves a better name 
than "flush_flags".  FWIW cc_compute_all isn't a bad name, if you're copying 
i386 anyway...

> -DEF_HELPER_2(flush_flags, void, env, i32)
> +DEF_HELPER_2(flush_flags, i32, env, i32)

Modify to use DEF_HELPER_FLAGS while you're at it.  At the moment it reads some 
globals, but doesn't write any, or have any other side effects.

>   static inline void gen_flush_flags(DisasContext *s)
>   {
>       if (s->cc_op == CC_OP_FLAGS)
>           return;
> -    gen_flush_cc_op(s);
> -    gen_helper_flush_flags(cpu_env, QREG_CC_OP);
> -    s->cc_op = CC_OP_FLAGS;
> +    if (s->cc_op == CC_OP_DYNAMIC) {
> +        gen_helper_flush_flags(QREG_CC_DEST, cpu_env, QREG_CC_OP);
> +    } else {
> +        gen_helper_flush_flags(QREG_CC_DEST, cpu_env, tcg_const_i32(s->cc_op));
> +    }

That const needs to be freed.

> @@ -1248,7 +1294,6 @@ DISAS_INSN(bitop_im)
>           DEST_EA(env, insn, opsize, tmp, &addr);
>       }
>   }
> -
>   DISAS_INSN(arith_im)
>   {
>       int op;

Careful with the errant whitespace changes.

> @@ -1706,16 +1745,18 @@ DISAS_INSN(branch)
>           /* bsr */
>           gen_push(s, tcg_const_i32(s->pc));
>       }
> -    gen_flush_cc_op(s);
>       if (op > 1) {
>           /* Bcc */
>           l1 = gen_new_label();
>           gen_jmpcc(s, ((insn >> 8) & 0xf) ^ 1, l1);
> +        update_cc_op(s);
>           gen_jmp_tb(s, 1, base + offset);
>           gen_set_label(l1);
> +        update_cc_op(s);
>           gen_jmp_tb(s, 0, s->pc);

Ideally you'd do this only once, before the jmpcc.


r~