From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xen.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Jan Beulich <JBeulich@suse.com>
Subject: [PATCH 4/4] x86/memcpy: Reduce code size
Date: Tue, 2 Jun 2015 15:04:27 +0100 [thread overview]
Message-ID: <1433253867-29752-5-git-send-email-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <1433253867-29752-1-git-send-email-andrew.cooper3@citrix.com>
'n % BYTES_PER_LONG' is at most 7, and doesn't need a 64bit register mov.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
---
Admittedly very trivial, but no need to be wasteful
---
xen/arch/x86/string.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/xen/arch/x86/string.c b/xen/arch/x86/string.c
index 3af0ea8..043ae66 100644
--- a/xen/arch/x86/string.c
+++ b/xen/arch/x86/string.c
@@ -15,7 +15,7 @@ void *memcpy(void *dest, const void *src, size_t n)
asm volatile (
" rep ; movs"__OS" ; "
- " mov %4,%3 ; "
+ " mov %k4,%k3 ; "
" rep ; movsb "
: "=&c" (d0), "=&D" (d1), "=&S" (d2)
: "0" (n/BYTES_PER_LONG), "r" (n%BYTES_PER_LONG), "1" (dest), "2" (src)
--
1.7.10.4
prev parent reply other threads:[~2015-06-02 14:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-02 14:04 [PATCH 0/4] x86/xen Several unassociated fixes Andrew Cooper
2015-06-02 14:04 ` [PATCH 1/4] x86/apic: Disable the LAPIC later in smp_send_stop() Andrew Cooper
2015-06-02 14:04 ` [PATCH 2/4] xen/crash: Don't use set_fixmap() in the crash path Andrew Cooper
2015-06-02 14:04 ` [PATCH 3/4] x86/debugger: Use copy_to/from_guest() in dbg_rw_guest_mem() Andrew Cooper
2015-06-02 14:04 ` Andrew Cooper [this message]
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