如何使用RDRAND内部函数? [英] How to use RDRAND intrinsics?
问题描述
我在看HJ Lu的补丁:更新x86 rdrand内在的。我不知道是否应该使用 _rdrand_u64
, _rdrand64_step
,或者是否有其他功能。看起来没有为他们编写测试用例。
似乎缺少手册页(来自Ubuntu 14,GCC 4.8.4):
p> $ man -k rdrand
rdrand:没有什么合适的。
如何使用 RDRAND
intrinsics生成一个32字节的块?
相关的问题是 RDRAND和RDSEED内部函数GCC和Intel C ++ 。但它并没有告诉我如何使用它们,或者如何生成一个块。
$ c>< immintrin.h> (我在`/usr/lib/gcc/x86_64-linux-gnu/4.9/include/',Ubuntu 15.04 64bit)中,有兼容的MSVC,Intel CC)定义了将数据传递回GCC内置函数的函数
extern __inline int __attribute __((__ gnu_inline__,__always_inline__, __artificial__))
_rdrand64_step(unsigned long long * __ P)
{
return __builtin_ia32_rdrand64_step(__P);
}
用于64位参数,另外两个用于16位和32位参数
_rdrand16_step(unsigned short * __ P)
_rdrand32_step(unsigned int * __ P)
您应该使用这些代码以便您的代码与MSVC,Intel CC和其他编译器兼容。
_rdrand64_step
将填充64位参数,通过指针传递,随机位并返回错误代码。同上为32位和16位版本
更新
这些内在函数生成随机数16/32/64位生成的随机值被写入给定的内存位置,并返回成功状态:如果硬件返回了一个有效的随机值,则为'1',否则为'0'。
https://software.intel.com/en-us/node / 523864
I was looking at H.J. Lu's PATCH: Update x86 rdrand intrinsics. I can't tell if I should be using _rdrand_u64
, _rdrand64_step
, or if there are other function(s). There does not appear to be test cases written for them.
There also seems to be a lack of man pages (from Ubuntu 14, GCC 4.8.4):
$ man -k rdrand
rdrand: nothing appropriate.
How does one use the RDRAND
intrinsics to generate, say, a block of 32 bytes?
A related question is RDRAND and RDSEED intrinsics GCC and Intel C++. But it does not tell me how to use them, or how to generate a block.
If you look at <immintrin.h>
(mine is in `/usr/lib/gcc/x86_64-linux-gnu/4.9/include/', Ubuntu 15.04 64bit), there are compatible (with MSVC, Intel CC) functions defined which pass data back to GCC built-ins
extern __inline int __attribute__((__gnu_inline__, __always_inline__, __artificial__))
_rdrand64_step (unsigned long long *__P)
{
return __builtin_ia32_rdrand64_step (__P);
}
for 64bit parameter and two others for 16 bit and 32bit parameters
_rdrand16_step (unsigned short *__P)
_rdrand32_step (unsigned int *__P)
You supposed to use those so your code would be compatible with MSVC, Intel CC and other compilers.
_rdrand64_step
will fill 64bit parameter, passed by pointer, with random bits and return error code. Ditto for 32bit and 16bit versions
UPDATE
"These intrinsics generate random numbers of 16/32/64 bit wide random integers. The generated random value is written to the given memory location and the success status is returned: '1' if the hardware returned a valid random value, and '0' otherwise."
https://software.intel.com/en-us/node/523864
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