Re: [Qemu-devel] [PATCH 2/2] lsi: use ldn_le_p()/stn_le_p()

[Philippe Mathieu-Daudé]

Hi Sven,

On 2/18/19 6:55 PM, Sven Schnelle wrote:
> Signed-off-by: Sven Schnelle <address@hidden>
> ---
>  hw/scsi/lsi53c895a.c | 19 ++-----------------
>  1 file changed, 2 insertions(+), 17 deletions(-)
> 
> diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c
> index c493e3c4c7..93c4434bfb 100644
> --- a/hw/scsi/lsi53c895a.c
> +++ b/hw/scsi/lsi53c895a.c
> @@ -2078,29 +2078,14 @@ static void lsi_ram_write(void *opaque, hwaddr addr,
>                            uint64_t val, unsigned size)
>  {
>      LSIState *s = opaque;
> -    uint32_t newval;
> -    uint32_t mask;
> -    int shift;
> -
> -    newval = s->script_ram[addr >> 2];
> -    shift = (addr & 3) * 8;
> -    mask = ((uint64_t)1 << (size * 8)) - 1;
> -    newval &= ~(mask << shift);
> -    newval |= val << shift;
> -    s->script_ram[addr >> 2] = newval;
> +    stn_le_p(((void*)s->script_ram) + addr, size, val);

If you want to do pointer arithmetic, it is safer to cast to a uintptr_t.
But since you update all the places that use script_ram[], it seems
pointless to keep it as an array of uint32_t. We can simply convert it
to an array of char.

Your patch looks sane otherwise,

Thanks,

Phil.

>  }
>  
>  static uint64_t lsi_ram_read(void *opaque, hwaddr addr,
>                               unsigned size)
>  {
>      LSIState *s = opaque;
> -    uint32_t val;
> -    uint32_t mask;
> -
> -    val = s->script_ram[addr >> 2];
> -    mask = ((uint64_t)1 << (size * 8)) - 1;
> -    val >>= (addr & 3) * 8;
> -    return val & mask;
> +    return ldn_le_p(((void *)s->script_ram) + addr, size);
>  }
>  
>  static const MemoryRegionOps lsi_ram_ops = {
>