From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33345) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZfUZR-00031O-Sm for qemu-devel@nongnu.org; Fri, 25 Sep 2015 11:06:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZfUZM-00037o-4B for qemu-devel@nongnu.org; Fri, 25 Sep 2015 11:05:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41830) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZfUZL-00036d-Ph for qemu-devel@nongnu.org; Fri, 25 Sep 2015 11:05:52 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (Postfix) with ESMTPS id 50F359239A for ; Fri, 25 Sep 2015 15:05:51 +0000 (UTC) From: Laurent Vivier Date: Fri, 25 Sep 2015 16:09:06 +0200 Message-Id: <1443190150-17312-6-git-send-email-lvivier@redhat.com> In-Reply-To: <1443190150-17312-1-git-send-email-lvivier@redhat.com> References: <1443190150-17312-1-git-send-email-lvivier@redhat.com> Subject: [Qemu-devel] [PULL 5/9] openrisc: remove muldiv64() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: pbonzini@redhat.com Cc: Laurent Vivier , qemu-devel@nongnu.org Originally, timers were ticks based, and it made sense to add ticks to current time to know when to trigger an alarm. But since commit: 7447545 change all other clock references to use nanosecond resolution accessors All timers use nanoseconds and we need to convert ticks to nanoseconds, by doing something like: y = muldiv64(x, get_ticks_per_sec(), TIMER_FREQ) where x is the number of device ticks and y the number of system ticks. y is used as nanoseconds in timer functions, it works because 1 tick is 1 nanosecond. (get_ticks_per_sec() is 10^9) But as openrisc timer frequency is 20 MHz, we can also do: y = x * 50; /* 20 MHz period is 50 ns */ Signed-off-by: Laurent Vivier --- hw/openrisc/cputimer.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/hw/openrisc/cputimer.c b/hw/openrisc/cputimer.c index 9c54945..560cb91 100644 --- a/hw/openrisc/cputimer.c +++ b/hw/openrisc/cputimer.c @@ -22,7 +22,7 @@ #include "hw/hw.h" #include "qemu/timer.h" -#define TIMER_FREQ (20 * 1000 * 1000) /* 20MHz */ +#define TIMER_PERIOD 50 /* 50 ns period for 20 MHz timer */ /* The time when TTCR changes */ static uint64_t last_clk; @@ -36,8 +36,7 @@ void cpu_openrisc_count_update(OpenRISCCPU *cpu) return; } now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); - cpu->env.ttcr += (uint32_t)muldiv64(now - last_clk, TIMER_FREQ, - get_ticks_per_sec()); + cpu->env.ttcr += (uint32_t)((now - last_clk) / TIMER_PERIOD); last_clk = now; } @@ -59,7 +58,7 @@ void cpu_openrisc_timer_update(OpenRISCCPU *cpu) } else { wait = (cpu->env.ttmr & TTMR_TP) - (cpu->env.ttcr & TTMR_TP); } - next = now + muldiv64(wait, get_ticks_per_sec(), TIMER_FREQ); + next = now + (uint64_t)wait * TIMER_PERIOD; timer_mod(cpu->env.timer, next); } -- 2.1.0