From: Jike Song Date: Fri, 17 Oct 2008 05:25:07 +0000 (+0800) Subject: x86: clean up comments wrt. rd{msr|tsc|pmc} X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d4f1b10365d4f03dd802433e0014cf503e6e930c;p=mv-sheeva.git x86: clean up comments wrt. rd{msr|tsc|pmc} The rdmsr instruction(et al) for i386 and x86-64 are semantically same. The only difference is how gcc interpret constraint "A" for these targets. Signed-off-by: Jike Song Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 46be2fa7ac2..478a9245aae 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -22,10 +22,10 @@ static inline unsigned long long native_read_tscp(unsigned int *aux) } /* - * i386 calling convention returns 64-bit value in edx:eax, while - * x86_64 returns at rax. Also, the "A" constraint does not really - * mean rdx:rax in x86_64, so we need specialized behaviour for each - * architecture + * both i386 and x86_64 returns 64-bit value in edx:eax, but gcc's "A" + * constraint has different meanings. For i386, "A" means exactly + * edx:eax, while for x86_64 it doesn't mean rdx:rax or edx:eax. Instead, + * it means rax *or* rdx. */ #ifdef CONFIG_X86_64 #define DECLARE_ARGS(val, low, high) unsigned low, high