From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Jay Cliburn <jcliburn@gmail.com>, Chris Snook <chris.snook@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] atheros/atlx: Simplify bit manipulations
Date: Fri, 23 Jan 2015 12:06:52 +0100 [thread overview]
Message-ID: <1422011212-30095-1-git-send-email-linux@rasmusvillemoes.dk> (raw)
The code 'if (foo & X) foo &= ~X;' is semantically equivalent to
simply 'foo &= ~X;', but gcc generates about four instructions for the
former, one for the latter. Similarly, if X consists of a single bit,
'if (!(foo & X)) X |= X;' can be replaced by 'foo |= X;'.
In the atl2 case, gcc does know how to merge the new adjacent
operations, so altogether this gives a nice little code size
reduction of about 80 bytes.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
drivers/net/ethernet/atheros/atlx/atl1.c | 3 +--
drivers/net/ethernet/atheros/atlx/atl2.c | 12 ++++--------
2 files changed, 5 insertions(+), 10 deletions(-)
diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c
index 2c8f398aeda9..d9d61d6e8386 100644
--- a/drivers/net/ethernet/atheros/atlx/atl1.c
+++ b/drivers/net/ethernet/atheros/atlx/atl1.c
@@ -1667,8 +1667,7 @@ static void atl1_via_workaround(struct atl1_adapter *adapter)
unsigned long value;
value = ioread16(adapter->hw.hw_addr + PCI_COMMAND);
- if (value & PCI_COMMAND_INTX_DISABLE)
- value &= ~PCI_COMMAND_INTX_DISABLE;
+ value &= ~PCI_COMMAND_INTX_DISABLE;
iowrite32(value, adapter->hw.hw_addr + PCI_COMMAND);
}
diff --git a/drivers/net/ethernet/atheros/atlx/atl2.c b/drivers/net/ethernet/atheros/atlx/atl2.c
index 84a09e8ddd9c..46d1b959daa8 100644
--- a/drivers/net/ethernet/atheros/atlx/atl2.c
+++ b/drivers/net/ethernet/atheros/atlx/atl2.c
@@ -1278,14 +1278,10 @@ static void atl2_setup_pcicmd(struct pci_dev *pdev)
pci_read_config_word(pdev, PCI_COMMAND, &cmd);
- if (cmd & PCI_COMMAND_INTX_DISABLE)
- cmd &= ~PCI_COMMAND_INTX_DISABLE;
- if (cmd & PCI_COMMAND_IO)
- cmd &= ~PCI_COMMAND_IO;
- if (0 == (cmd & PCI_COMMAND_MEMORY))
- cmd |= PCI_COMMAND_MEMORY;
- if (0 == (cmd & PCI_COMMAND_MASTER))
- cmd |= PCI_COMMAND_MASTER;
+ cmd &= ~PCI_COMMAND_INTX_DISABLE;
+ cmd &= ~PCI_COMMAND_IO;
+ cmd |= PCI_COMMAND_MEMORY;
+ cmd |= PCI_COMMAND_MASTER;
pci_write_config_word(pdev, PCI_COMMAND, cmd);
/*
--
2.1.3
next reply other threads:[~2015-01-23 11:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-23 11:06 Rasmus Villemoes [this message]
2015-01-23 20:26 ` Francois Romieu
2015-01-25 7:35 ` David Miller
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=1422011212-30095-1-git-send-email-linux@rasmusvillemoes.dk \
--to=linux@rasmusvillemoes.dk \
--cc=chris.snook@gmail.com \
--cc=jcliburn@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®