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Preserve (e|r)bx register when calling cpuid

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This commit is contained in:
Frank Denis 2014-05-02 20:39:51 -07:00
parent b1c79463e0
commit f601e6e471
1 changed files with 11 additions and 2 deletions
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13
src/libsodium/sodium/runtime.c
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@ -46,10 +46,19 @@ _cpuid(unsigned int cpu_info[4U], const unsigned int cpu_info_type)
#ifdef _MSC_VER
__cpuidex((int *) cpu_info, cpu_info_type, 0);
#elif defined(HAVE_CPUID)
__asm__ __volatile__ ("cpuid" :
"=a" (cpu_info[0]), "=b" (cpu_info[1]),
# ifdef __x86_64__
__asm__ __volatile__ ("xchgq %%rbx, %q1; cpuid; xchgq %%rbx, %q1" :
"=a" (cpu_info[0]), "=&r" (cpu_info[1]),
"=c" (cpu_info[2]), "=d" (cpu_info[3]) :
"a" (cpu_info_type), "c" (0U));
# elif defined(__i386__)
__asm__ __volatile__ ("xchgl %%ebx, %k1; cpuid; xchgl %%ebx, %k1" :
"=a" (cpu_info[0]), "=&r" (cpu_info[1]),
"=c" (cpu_info[2]), "=d" (cpu_info[3]) :
"0" (cpu_info_type), "2" (0U));
# else
cpu_info[0] = cpu_info[1] = cpu_info[2] = cpu_info[3] = 0;
# endif
#else
cpu_info[0] = cpu_info[1] = cpu_info[2] = cpu_info[3] = 0;
#endif