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 <lviv...@redhat.com>
Reviewed-by: Peter Crosthwaite <crosthwaite.pe...@gmail.com>
Acked-by: Peter Maydell <peter.mayd...@linaro.org>
---
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 12ea88f..8367997 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,
@@ -706,8 +708,8 @@ 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 */
@@ -745,8 +747,8 @@ 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 */
@@ -766,8 +768,8 @@ 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
