Re: [Qemu-devel] [PATCH 05/10] qemu-tech: document lazy condition code evaluation in cpu.h

[Emilio G. Cota]

On Thu, Oct 06, 2016 at 17:24:18 +0200, Paolo Bonzini wrote:
> Unlike the other sections, they are pretty specific to a particular CPU.
> 
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
>  qemu-tech.texi     | 25 -------------------------
>  target-cris/cpu.h  |  7 +++++++
>  target-i386/cpu.h  |  7 +++++++
>  target-m68k/cpu.h  |  8 ++++++++
>  target-sparc/cpu.h |  5 +++++
>  5 files changed, 27 insertions(+), 25 deletions(-)
(snip)
> diff --git a/target-cris/cpu.h b/target-cris/cpu.h
> index 7d7fe6e..6d3de56 100644
> --- a/target-cris/cpu.h
> +++ b/target-cris/cpu.h
> @@ -223,6 +223,13 @@ int cpu_cris_signal_handler(int host_signum, void *pinfo,
>  void cris_initialize_tcg(void);
>  void cris_initialize_crisv10_tcg(void);
>  
> +/* Instead of computing the condition codes after each x86 instruction,
> + * QEMU just stores one operand (called CC_SRC), the result
> + * (called CC_DST) and the type of operation (called CC_OP). When the
> + * condition codes are needed, the condition codes can be calculated
> + * using this information. Condition codes are not generated if they
> + * are only needed for conditional branches.
> + */

This text doesn't seem to be cris-specific, e.g.:
- "each x86 instruction"
- CC_SRC (git grep CC_SRC here doesn't return anything)
- CC_DST (ditto)

>  enum {
>      CC_OP_DYNAMIC, /* Use env->cc_op  */
>      CC_OP_FLAGS,
> diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> index 6d028aa..f606f15 100644
> --- a/target-i386/cpu.h
> +++ b/target-i386/cpu.h
> @@ -698,6 +698,13 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
>  /* Use a clearer name for this.  */
>  #define CPU_INTERRUPT_INIT      CPU_INTERRUPT_RESET
>  
> +/* Instead of computing the condition codes after each x86 instruction,
> + * QEMU just stores one operand (called CC_SRC), the result
> + * (called CC_DST) and the type of operation (called CC_OP). When the
> + * condition codes are needed, the condition codes can be calculated
> + * using this information. Condition codes are not generated if they
> + * are only needed for conditional branches.
> + */
>  typedef enum {
>      CC_OP_DYNAMIC, /* must use dynamic code to get cc_op */
>      CC_OP_EFLAGS,  /* all cc are explicitly computed, CC_SRC = flags */
> diff --git a/target-m68k/cpu.h b/target-m68k/cpu.h
> index c2d40cb..ccc7157 100644
> --- a/target-m68k/cpu.h
> +++ b/target-m68k/cpu.h
> @@ -154,6 +154,14 @@ int cpu_m68k_signal_handler(int host_signum, void *pinfo,
>                             void *puc);
>  void cpu_m68k_flush_flags(CPUM68KState *, int);
>  
> +
> +/* Instead of computing the condition codes after each x86 instruction,
> + * QEMU just stores one operand (called CC_SRC), the result
> + * (called CC_DST) and the type of operation (called CC_OP). When the
> + * condition codes are needed, the condition codes can be calculated
> + * using this information. Condition codes are not generated if they
> + * are only needed for conditional branches.
> + */

Same as above:
- "each x86 instruction"
- no CC_DST

                Emilio