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[Qemu-devel] [PATCH v3 6/9] arm: clarify the use of muldiv64()
From: |
Laurent Vivier |
Subject: |
[Qemu-devel] [PATCH v3 6/9] arm: clarify the use of muldiv64() |
Date: |
Thu, 27 Aug 2015 21:33:04 +0200 |
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 <address@hidden>
---
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
- [Qemu-devel] [PATCH v3 0/9] remove useless muldiv64(), Laurent Vivier, 2015/08/27
- [Qemu-devel] [PATCH v3 1/9] i6300esb: remove muldiv64(), Laurent Vivier, 2015/08/27
- [Qemu-devel] [PATCH v3 2/9] rtl8139: remove muldiv64(), Laurent Vivier, 2015/08/27
- [Qemu-devel] [PATCH v3 3/9] pcnet: remove muldiv64(), Laurent Vivier, 2015/08/27
- [Qemu-devel] [PATCH v3 4/9] mips: remove muldiv64(), Laurent Vivier, 2015/08/27
- [Qemu-devel] [PATCH v3 5/9] openrisc: remove muldiv64(), Laurent Vivier, 2015/08/27
- [Qemu-devel] [PATCH v3 6/9] arm: clarify the use of muldiv64(),
Laurent Vivier <=
- [Qemu-devel] [PATCH v3 7/9] hpet: remove muldiv64(), Laurent Vivier, 2015/08/27
- [Qemu-devel] [PATCH v3 8/9] bt: remove muldiv64(), Laurent Vivier, 2015/08/27
- [Qemu-devel] [PATCH v3 9/9] net: remove muldiv64(), Laurent Vivier, 2015/08/27