Re: [Qemu-devel] [PATCH v3 7/9] hpet: remove muldiv64()

[Laurent Vivier]

ping ?

On 27/08/2015 21:33, Laurent Vivier wrote:
> hpet defines a clock period in femtoseconds but
> then converts it to nanoseconds to use the internal
> timers.
> 
> We can define the period in nanoseconds and use it
> directly, this allows to remove muldiv64().
> 
> We only need to convert the period to femtoseconds
> to put it in internal hpet capability register.
> 
> Signed-off-by: Laurent Vivier <address@hidden>
> ---
>  hw/timer/hpet.c         | 6 +++---
>  include/hw/timer/hpet.h | 4 ++--
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
> index 2bb6221..3037bef 100644
> --- a/hw/timer/hpet.c
> +++ b/hw/timer/hpet.c
> @@ -126,12 +126,12 @@ static uint32_t hpet_time_after64(uint64_t a, uint64_t 
> b)
>  
>  static uint64_t ticks_to_ns(uint64_t value)
>  {
> -    return (muldiv64(value, HPET_CLK_PERIOD, FS_PER_NS));
> +    return value * HPET_CLK_PERIOD;
>  }
>  
>  static uint64_t ns_to_ticks(uint64_t value)
>  {
> -    return (muldiv64(value, FS_PER_NS, HPET_CLK_PERIOD));
> +    return value / HPET_CLK_PERIOD;
>  }
>  
>  static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old, uint64_t mask)
> @@ -758,7 +758,7 @@ static void hpet_realize(DeviceState *dev, Error **errp)
>      /* 64-bit main counter; LegacyReplacementRoute. */
>      s->capability = 0x8086a001ULL;
>      s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
> -    s->capability |= ((HPET_CLK_PERIOD) << 32);
> +    s->capability |= ((uint64_t)(HPET_CLK_PERIOD * FS_PER_NS) << 32);
>  
>      qdev_init_gpio_in(dev, hpet_handle_legacy_irq, 2);
>      qdev_init_gpio_out(dev, &s->pit_enabled, 1);
> diff --git a/include/hw/timer/hpet.h b/include/hw/timer/hpet.h
> index 773953b..d872909 100644
> --- a/include/hw/timer/hpet.h
> +++ b/include/hw/timer/hpet.h
> @@ -16,9 +16,9 @@
>  #include "qom/object.h"
>  
>  #define HPET_BASE               0xfed00000
> -#define HPET_CLK_PERIOD         10000000ULL /* 10000000 femtoseconds == 
> 10ns*/
> +#define HPET_CLK_PERIOD         10 /* 10 ns*/
>  
> -#define FS_PER_NS 1000000
> +#define FS_PER_NS 1000000       /* 1000000 femtoseconds == 1 ns */
>  #define HPET_MIN_TIMERS         3
>  #define HPET_MAX_TIMERS         32
>  
>