From: Eric Blake <eblake@redhat.com>
To: li guang <lig.fnst@cn.fujitsu.com>
Cc: blauwirbel@gmail.com, pingfank@linux.vnet.ibm.com,
gleb@redhat.com, stefanha@gmail.com, seabios@seabios.org,
qemu-devel@nongnu.org,
Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>,
kevin@koconnor.net, kraxel@redhat.com, anthony@codemonkey.ws
Subject: Re: [Qemu-devel] [RFC PATCH v4 07/30] Add SIZE type to qdev properties
Date: Wed, 20 Mar 2013 08:24:24 -0600 [thread overview]
Message-ID: <5149C698.9070501@redhat.com> (raw)
In-Reply-To: <1363759577.21129.237.camel@liguang.fnst.cn.fujitsu.com>
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On 03/20/2013 12:06 AM, li guang wrote:
>> + return snprintf(dest, len, "%0.03f%c", (double)*ptr/div, suffixes[i]);
> ^^^^^^ ^^^^^^^^^^^^^^^
>> +}
>> +
>
> IMHO, you may need (double)(*ptr/div), for type cast is right
> associated.
No, the code as written is correct, and your proposal would be wrong.
As written, it is evaluated as:
((double)*ptr) / div
which promotes the division to floating point. Your proposal would do
the division (*ptr/div) as an integral (truncating) division, and only
then cast the result to double.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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next prev parent reply other threads:[~2013-03-20 14:24 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-18 12:41 [Qemu-devel] [RFC PATCH v4 00/30] ACPI memory hotplug Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 01/30] [SeaBIOS] Add ACPI_EXTRACT_DEVICE* macros Vasilis Liaskovitis
2013-03-20 3:28 ` li guang
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 02/30] [SeaBIOS] Add SSDT memory device support Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 03/30] [SeaBIOS] acpi-dsdt: Implement functions for memory hotplug Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 04/30] [SeaBIOS] acpi: generate hotplug memory devices Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 05/30] [SeaBIOS] q35: Add memory hotplug handler Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 06/30] qapi: make visit_type_size fallback to type_int Vasilis Liaskovitis
2013-01-09 0:18 ` Andreas Färber
2013-01-09 16:00 ` mdroth
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 07/30] Add SIZE type to qdev properties Vasilis Liaskovitis
2013-03-20 6:06 ` li guang
2013-03-20 14:24 ` Eric Blake [this message]
2013-03-21 0:39 ` li guang
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 08/30] qemu-option: export parse_option_number Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 09/30] Implement dimm device abstraction Vasilis Liaskovitis
2013-03-26 3:51 ` li guang
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 10/30] vl: handle "-device dimm" Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 11/30] acpi_piix4 : Implement memory device hotplug registers Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 12/30] acpi_ich9 " Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 13/30] piix_pci and pc_piix: refactor Vasilis Liaskovitis
2013-01-16 7:20 ` Hu Tao
2013-01-16 9:36 ` Vasilis Liaskovitis
2013-01-16 11:17 ` Andreas Färber
2013-01-16 17:10 ` Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 14/30] piix_pci: Add i440fx dram controller initialization Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 15/30] q35: " Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 16/30] pc: Add dimm paravirt SRAT info Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 17/30] [SeaBIOS] pci: Use paravirt interface for pcimem_start and pcimem64_start Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 18/30] Introduce paravirt interface QEMU_CFG_PCI_WINDOW Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 19/30] Implement "info memory-total" and "query-memory-total" Vasilis Liaskovitis
2012-12-19 19:47 ` Blue Swirl
2013-01-04 16:21 ` Eric Blake
2013-01-10 17:42 ` Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 20/30] balloon: update with hotplugged memory Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 21/30] Implement dimm-info Vasilis Liaskovitis
2013-01-08 23:20 ` Eric Blake
2013-01-10 17:45 ` Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 22/30] [SeaBIOS] acpi: add _EJ0 operation and eject port for memory devices Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 23/30] dimm: add hot-remove capability Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 24/30] acpi_piix4: " Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 25/30] acpi_ich9: " Vasilis Liaskovitis
2012-12-19 19:48 ` Blue Swirl
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 26/30] Implement qmp and hmp commands for notification lists Vasilis Liaskovitis
2013-01-09 0:23 ` Eric Blake
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 27/30] [SeaBIOS] Add _OST dimm method Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 28/30] Add _OST dimm support Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 29/30] [SeaBIOS] Implement _PS3 method for memory device Vasilis Liaskovitis
2012-12-18 12:41 ` [Qemu-devel] [RFC PATCH v4 30/30] Implement _PS3 for dimm Vasilis Liaskovitis
2012-12-18 16:45 ` [Qemu-devel] [RFC PATCH v4 00/30] ACPI memory hotplug Zhi Yong Wu
2012-12-19 11:40 ` Vasilis Liaskovitis
2012-12-19 7:27 ` Gerd Hoffmann
2012-12-19 11:35 ` Vasilis Liaskovitis
2012-12-19 13:56 ` Gerd Hoffmann
2013-01-10 18:57 ` Vasilis Liaskovitis
2013-03-19 6:30 ` li guang
2013-03-26 16:58 ` Vasilis Liaskovitis
2013-03-27 2:42 ` li guang
2013-04-02 9:15 ` liu ping fan
2013-01-09 0:08 ` Andreas Färber
2013-01-10 17:36 ` Vasilis Liaskovitis
2013-01-10 17:55 ` Andreas Färber
2013-03-20 6:18 ` li guang
2013-03-26 14:20 ` Eduardo Habkost
2013-03-27 7:39 ` li guang
[not found] ` <CAF+CadtnTcOnUt7jp1bARJgioxR5KzLG0QSQuDbiqhiKxiCqFA@mail.gmail.com>
[not found] ` <20130228101819.GA4370@dhcp-192-168-178-175.profitbricks.localdomain>
2013-03-19 7:28 ` li guang
2013-03-26 16:43 ` Vasilis Liaskovitis
2013-03-27 2:54 ` li guang
2013-03-28 9:29 ` Vasilis Liaskovitis
2013-03-28 9:49 ` liu ping fan
2013-03-26 14:47 ` Luiz Capitulino
2013-03-26 16:59 ` Vasilis Liaskovitis
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