On 01/07/2011 22:22, Scott Wood wrote:
> On Fri, 1 Jul 2011 16:13:41 +0200
> Fabien Chouteau <chout...@adacore.com> wrote:
>> +static void booke_update_fixed_timer(CPUState *env,
>> + uint8_t target_bit,
>> + uint64_t *next,
>> + struct QEMUTimer *timer)
>> +{
>> + ppc_tb_t *tb_env = env->tb_env;
>> + uint64_t lapse;
>> + uint64_t tb;
>> + uint64_t period = 1 << (target_bit + 1);
>> + uint64_t now;
>> +
>> + now = qemu_get_clock_ns(vm_clock);
>> + tb = cpu_ppc_get_tb(tb_env, now, tb_env->tb_offset);
>> +
>> + if (tb <= (1 << target_bit)) {
>> + lapse = (1 << target_bit) - tb;
>> + } else {
>> + lapse = period - ((tb - (1 << target_bit)) % period);
>
> We know period is a power of two, so just do "& (period - 1)".
>
> That should let you get rid of the special case for
> "tb <= (1 << target_bit)" as well.
>
Do you mean "lapse = period - ((tb - (1 << target_bit)) & (period - 1));" ?
I don't see how this solves the "tb <= (1 << target_bit)" case.
--
Fabien Chouteau
