On Thu, Aug 27, 2015 at 12:33 PM, Laurent Vivier <[email protected]> wrote: > muldiv64() is used to convert microseconds into CPU ticks. > > But it is not clear and not commented. This patch uses macro > to clearly identify what is used: time, CPU frequency and ticks. > For an elapsed time and a given frequency, we compute how many ticks > we have. > > Signed-off-by: Laurent Vivier <[email protected]>
Reviewed-by: Peter Crosthwaite <[email protected]> > --- > v2: replace "arm: remove muldiv64()" > target-arm/helper.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) > > diff --git a/target-arm/helper.c b/target-arm/helper.c > index 7df1f06..4455761 100644 > --- a/target-arm/helper.c > +++ b/target-arm/helper.c > @@ -12,6 +12,8 @@ > #include <zlib.h> /* For crc32 */ > #include "exec/semihost.h" > > +#define ARM_CPU_FREQ 1000000000 /* FIXME: 1 GHz, should be configurable */ > + > #ifndef CONFIG_USER_ONLY > static inline bool get_phys_addr(CPUARMState *env, target_ulong address, > int access_type, ARMMMUIdx mmu_idx, > @@ -678,8 +680,8 @@ 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 = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL), > + ARM_CPU_FREQ, NANOSECONDS_PER_SECOND); > > if (env->cp15.c9_pmcr & PMCRD) { > /* Increment once every 64 processor clock cycles */ > @@ -717,8 +719,8 @@ 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 = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL), > + ARM_CPU_FREQ, NANOSECONDS_PER_SECOND); > > if (env->cp15.c9_pmcr & PMCRD) { > /* Increment once every 64 processor clock cycles */ > @@ -738,8 +740,8 @@ 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 = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL), > + ARM_CPU_FREQ, NANOSECONDS_PER_SECOND); > > if (env->cp15.c9_pmcr & PMCRD) { > /* Increment once every 64 processor clock cycles */ > -- > 2.1.0 > >
