intrinsics

问题 I've got a little C++ project that was developed for Win32 and I want to port it to OSX. The code uses functions like _bittest and _bittest64 but I haven't found same functions in the XCode header files. What could be an alternative for these functions? May be there are good working polyfills. The project is a legacy indeed, no extra performance is required at the moment. 回答1: The _bittest and _bittest64 symbols are compiler intrinsics, that emit Bit-test instructions, specifically x86 bt, to

问题 Renderscript intrinsics is very fast and useful. However, there are situations where we might want to build our own intrinsics, e.g. current convolution doesn't support the "valid" mode as in matlab. It would be very nice to have it. So, I'm wondering if it's possible to do so and connect nicely with the java layer (just like the existing intrinsics)? If it's possible, would you sketch how? Thank you. 回答1: no, there's no way to add custom intrinsics right now. in the next release we're

来源： https://stackoverflow.com/questions/61165307/vectorize-random-init-and-print-for-bigint-with-decimal-digit-array-with-avx2

来源： https://stackoverflow.com/questions/61165307/vectorize-random-init-and-print-for-bigint-with-decimal-digit-array-with-avx2

来源： https://stackoverflow.com/questions/61165307/vectorize-random-init-and-print-for-bigint-with-decimal-digit-array-with-avx2

来源： https://stackoverflow.com/questions/54409300/how-to-compile-program-with-mm-clflushopt-function-error-inlining-failed

来源： https://stackoverflow.com/questions/54409300/how-to-compile-program-with-mm-clflushopt-function-error-inlining-failed

问题 In Windows X86, the CPU brand can be queried with cpuid intrinsic function. Here is a sample of the code: #include <stdio.h> #include <intrin.h> int main(void) { int cpubrand[4 * 3]; __cpuid(&cpubrand[0], 0x80000002); __cpuid(&cpubrand[4], 0x80000003); __cpuid(&cpubrand[8], 0x80000004); char str[48]; memset(str, 0, sizeof str); memcpy(str, cpubrand, sizeof cpubrand); printf("%s\n", str); } What is the alternative of this in Windows ARM64? 回答1: Not a way to get name directly from the CPU

问题 For speed, I would like to read one of 8 registers referenced by the value in a 9th register. The fastest way I see to do this is to use 3 conditional jumps (checking 3 bits in the 9th register). This should have shorter latency than the standard way of doing this with an offset memory read, but this still requires at least 6 clock cycles (at least one test plus one conditional jmp per bit check). Is there any commercial CPU (preferably x86/x64) with an intrinsic to do this "offset register

问题 I am trying to write the equivalent of an if statement with SSE intrinsics. I am using __m128 _mm_cmplt_ps(__m128 a, __m128 b) to do the comparison a < b, and this returns 0xffffffff or 0x0 if the comparison was respectively true or false. I would like to convert these values into 1 and 0. In order to do this, is it correct to implement the logical "and" __m128 _mm_and_ps(__m128 c , __m128 d) , where c is the result of the conversion and d is, e.g., 0xffffffff ? Thank you for your attention.