From: Glauber Costa Date: Tue, 24 Jun 2008 13:21:25 +0000 (-0300) Subject: x86: explicitly use edx in const delay function. X-Git-Tag: v2.6.27-rc1~1106^2~46^2~39 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e58818d32c18197602d1869b22cfda99efd05fe;p=linux-2.6 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 Signed-off-by: H. Peter Anvin Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/lib/delay_32.c b/arch/x86/lib/delay_32.c index bf6de05445..0b659a320b 100644 --- a/arch/x86/lib/delay_32.c +++ b/arch/x86/lib/delay_32.c @@ -114,7 +114,7 @@ inline void __const_udelay(unsigned long xloops) int d0; xloops *= 4; - __asm__("mull %0" + __asm__("mull %%edx" :"=d" (xloops), "=&a" (d0) :"1" (xloops), "0" (cpu_data(raw_smp_processor_id()).loops_per_jiffy * (HZ/4))); diff --git a/arch/x86/lib/delay_64.c b/arch/x86/lib/delay_64.c index d0326d07c8..ff3dfecdb6 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)