From: Laurent Vivier <lvivier@redhat.com>
To: qemu-devel@nongnu.org, Peter Maydell <peter.maydell@linaro.org>,
qemu-trivial@nongnu.org
Subject: [Qemu-devel] [PATCH v3 6/9] arm: clarify the use of muldiv64()
Date: Thu, 27 Aug 2015 21:33:04 +0200 [thread overview]
Message-ID: <1440703987-29012-7-git-send-email-lvivier@redhat.com> (raw)
In-Reply-To: <1440703987-29012-1-git-send-email-lvivier@redhat.com>
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 <lvivier@redhat.com>
---
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
next prev parent reply other threads:[~2015-08-27 19:33 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-27 19:32 [Qemu-devel] [PATCH v3 0/9] remove useless muldiv64() Laurent Vivier
2015-08-27 19:32 ` [Qemu-devel] [PATCH v3 1/9] i6300esb: remove muldiv64() Laurent Vivier
2015-09-14 13:31 ` [Qemu-devel] [PATCH v4 " Laurent Vivier
2015-08-27 19:33 ` [Qemu-devel] [PATCH v3 2/9] rtl8139: " Laurent Vivier
2015-08-28 14:12 ` Stefan Hajnoczi
2015-08-27 19:33 ` [Qemu-devel] [PATCH v3 3/9] pcnet: " Laurent Vivier
2015-08-28 14:12 ` Stefan Hajnoczi
2015-08-27 19:33 ` [Qemu-devel] [PATCH v3 4/9] mips: " Laurent Vivier
2015-09-08 12:54 ` Laurent Vivier
2015-09-08 13:42 ` Leon Alrae
2015-08-27 19:33 ` [Qemu-devel] [PATCH v3 5/9] openrisc: " Laurent Vivier
2015-09-08 12:54 ` Laurent Vivier
2015-08-27 19:33 ` Laurent Vivier [this message]
2015-08-27 20:23 ` [Qemu-devel] [PATCH v3 6/9] arm: clarify the use of muldiv64() Peter Crosthwaite
2015-09-01 11:17 ` Peter Maydell
2015-09-01 11:23 ` Laurent Vivier
2015-09-01 11:30 ` Peter Maydell
2015-08-27 19:33 ` [Qemu-devel] [PATCH v3 7/9] hpet: remove muldiv64() Laurent Vivier
2015-09-08 12:55 ` Laurent Vivier
2015-09-08 12:58 ` Paolo Bonzini
2015-08-27 19:33 ` [Qemu-devel] [PATCH v3 8/9] bt: " Laurent Vivier
2015-09-08 12:55 ` Laurent Vivier
2015-09-08 12:57 ` Paolo Bonzini
2015-08-27 19:33 ` [Qemu-devel] [PATCH v3 9/9] net: " Laurent Vivier
2015-08-28 14:12 ` Stefan Hajnoczi
2015-09-24 16:21 ` [Qemu-devel] [PATCH v3 0/9] remove useless muldiv64() Laurent Vivier
2015-09-25 10:31 ` Paolo Bonzini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1440703987-29012-7-git-send-email-lvivier@redhat.com \
--to=lvivier@redhat.com \
--cc=peter.maydell@linaro.org \
--cc=qemu-devel@nongnu.org \
--cc=qemu-trivial@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.