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authorGlauber Costa <gcosta@redhat.com>2008-06-24 10:21:25 -0300
committerIngo Molnar <mingo@elte.hu>2008-07-09 08:52:04 +0200
commit7e58818d32c18197602d1869b22cfda99efd05fe (patch)
tree2ecdee4abda69dad3aefb25c04a81d43081ba01b /arch/x86/lib/delay_64.c
parenta76febe975997b933b7285b6e20bb0a21c09d453 (diff)
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x86: explicitly use edx in const delay function.
For x86_64, we can't just use %0, as it would generate a mul against rdx, which is not really what we want (note the ">> 32" in x86_64 version). Using a u64 variable with a shift in i386 generates bad code, so the solution is to explicitly use %%edx in inline assembly for both. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/lib/delay_64.c')
-rw-r--r--arch/x86/lib/delay_64.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/lib/delay_64.c b/arch/x86/lib/delay_64.c
index d0326d07c84..ff3dfecdb6f 100644
--- a/arch/x86/lib/delay_64.c
+++ b/arch/x86/lib/delay_64.c
@@ -103,9 +103,16 @@ EXPORT_SYMBOL(__delay);
inline void __const_udelay(unsigned long xloops)
{
- __delay(((xloops * HZ *
- cpu_data(raw_smp_processor_id()).loops_per_jiffy) >> 32) + 1);
+ int d0;
+ xloops *= 4;
+ __asm__("mull %%edx"
+ :"=d" (xloops), "=&a" (d0)
+ :"1" (xloops), "0"
+ (cpu_data(raw_smp_processor_id()).loops_per_jiffy * (HZ/4)));
+
+ __delay(++xloops);
}
+
EXPORT_SYMBOL(__const_udelay);
void __udelay(unsigned long usecs)