On 25/08/2015 23:11, Peter Crosthwaite wrote:
> On Tue, Aug 25, 2015 at 1:44 PM, Laurent Vivier <[email protected]> wrote:
>> muldiv64() is used to convert microseconds to nanoseconds.
>>
>> Use qemu_clock_get_ns() instead of qemu_clock_get_us()
>> to avoid this operation.
>>
>> Signed-off-by: Laurent Vivier <[email protected]>
>> ---
>> target-arm/helper.c | 9 +++------
>> 1 file changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/target-arm/helper.c b/target-arm/helper.c
>> index 1568aa6..f5e8fd8 100644
>> --- a/target-arm/helper.c
>> +++ b/target-arm/helper.c
>> @@ -678,8 +678,7 @@ void pmccntr_sync(CPUARMState *env)
>> {
>> uint64_t temp_ticks;
>>
>> - temp_ticks = muldiv64(qemu_clock_get_us(QEMU_CLOCK_VIRTUAL),
>> - get_ticks_per_sec(), 1000000);
>> + temp_ticks = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
>>
>> if (env->cp15.c9_pmcr & PMCRD) {
>> /* Increment once every 64 processor clock cycles */
>> @@ -717,8 +716,7 @@ static uint64_t pmccntr_read(CPUARMState *env, const
>> ARMCPRegInfo *ri)
>> return env->cp15.c15_ccnt;
>> }
>>
>> - total_ticks = muldiv64(qemu_clock_get_us(QEMU_CLOCK_VIRTUAL),
>> - get_ticks_per_sec(), 1000000);
>> + total_ticks = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
>>
>
> The long term goal here was to replace get_ticks_per_sec with a
> parameterizable CPU frequency so ideally the math should remain. The
> ARM CPU frequency == get_ticks_per_sec is the bigger issue.
OK, I will remove this one from the series.
Perhaps a comment in the original functions would help to understand
what we are doing here...
or something like that:
#define ARM_CPU_FREQ 1000000000 /* FIXME: should be parameterizable */
#define NSEC_PER_SEC 1000000000
total_ticks = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
ARM_CPU_FREQ, NSEC_PER_SEC);
Laurent
> Regards,
> Peter
>
>> if (env->cp15.c9_pmcr & PMCRD) {
>> /* Increment once every 64 processor clock cycles */
>> @@ -738,8 +736,7 @@ static void pmccntr_write(CPUARMState *env, const
>> ARMCPRegInfo *ri,
>> return;
>> }
>>
>> - total_ticks = muldiv64(qemu_clock_get_us(QEMU_CLOCK_VIRTUAL),
>> - get_ticks_per_sec(), 1000000);
>> + total_ticks = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
>>
>> if (env->cp15.c9_pmcr & PMCRD) {
>> /* Increment once every 64 processor clock cycles */
>> --
>> 2.1.0
>>
>>
