Re: [Qemu-devel] [PATCH 1/2] linux-user: ppc: mark as long long aligned

[malc]

On Sun, 30 Sep 2012, Alexander Graf wrote:

> The PPC32 ABI dictates that long long (64bit) parameters are pass in odd/even
> register pairs. Because unlike ARM and MIPS we start at an odd register 
> number,
> we can reuse the same aligning code that ARM and MIPS use.
> 
> Signed-off-by: Alexander Graf <address@hidden>
> ---
>  linux-user/syscall.c |    6 +++++-
>  1 files changed, 5 insertions(+), 1 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 1a38169..8cd56f2 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -587,12 +587,16 @@ extern int setfsgid(int);
>  extern int setgroups(int, gid_t *);
>  
>  /* ARM EABI and MIPS expect 64bit types aligned even on pairs or registers */
> -#ifdef TARGET_ARM 
> +#ifdef TARGET_ARM
>  static inline int regpairs_aligned(void *cpu_env) {
>      return ((((CPUARMState *)cpu_env)->eabi) == 1) ;
>  }
>  #elif defined(TARGET_MIPS)
>  static inline int regpairs_aligned(void *cpu_env) { return 1; }
> +#elif defined(TARGET_PPC) && !defined(TARGET_PPC64)
> +/* PPC32 expects 64bit parameters to be passed on odd/even pairs of registers
> +   which translates to the same as ARM/MIPS, because we start with r3 as 
> arg1 */

This is inaccurate, PPC32 doesn't expect anything, SysV ABI for PPC32,
which linux uses, does. This is linux-user so SysV ABI is a given but
still i'd reword it.

> +static inline int regpairs_aligned(void *cpu_env) { return 1; }
>  #else
>  static inline int regpairs_aligned(void *cpu_env) { return 0; }
>  #endif
> 

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