From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50255) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZUf53-0004OU-SJ for qemu-devel@nongnu.org; Wed, 26 Aug 2015 14:05:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZUf53-0000fM-2i for qemu-devel@nongnu.org; Wed, 26 Aug 2015 14:05:49 -0400 From: Laurent Vivier Date: Wed, 26 Aug 2015 20:05:35 +0200 Message-Id: <1440612338-5912-5-git-send-email-lvivier@redhat.com> In-Reply-To: <1440612338-5912-1-git-send-email-lvivier@redhat.com> References: <1440612338-5912-1-git-send-email-lvivier@redhat.com> Subject: [Qemu-devel] [PATCH v2 4/7] arm: clarify the use of muldiv64() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, Peter Maydell , crosthwaitepeter@gmail.com, qemu-trivial@nongnu.org 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 --- 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 /* 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