What is __m128d?

What is __m128d?

By : Md.Masud Hasan
Date : November 20 2020, 04:01 AM
like below fixes the issue I really can't get what "keyword" like __m128d is in C++. ,
Is it a typedef?
code :
// From gcc 7.3's emmintrin.h  (SSE2 extensions).  SSE1 stuff in xmmintrin.h

/* The Intel API is flexible enough that we must allow aliasing with other
   vector types, and their scalar components.  */
typedef long long __m128i __attribute__ ((__vector_size__ (16), __may_alias__));
typedef double __m128d __attribute__ ((__vector_size__ (16), __may_alias__));
__m128d a2 = { -1.388539L, 0.0L };

Share : facebook icon twitter icon
SSE: convert __m128 and __m128i into two __m128d

SSE: convert __m128 and __m128i into two __m128d

By : G0dl1ke
Date : March 29 2020, 07:55 AM
it should still fix some issue The intrinsics _mm_cvtepi32_pd and _mm_cvtps_pd convert the values to double.
This should be the loop:
code :
__m128i* base_addr = ...;
for( int i = 0; i < cnt; ++i )
    __m128i epi32 = _mm_load_si128( base_addr + i );
    __m128d v0 = _mm_cvtepi32_pd( epi32 );
    epi32 = _mm_srli_si128( epi32, 8 );
    __m128d v1 = _mm_cvtepi32_pd( epi32 );
are __m128, __m128d, __m256, etc built-in types in C++?

are __m128, __m128d, __m256, etc built-in types in C++?

By : AlexWeh
Date : March 29 2020, 07:55 AM
This might help you All are correct. These types are extensions to C++, not built in (almost nothing built into C++ begins with underscores). Since they are extensions, the implementation is free to impose any restrictions on them it wants.
Convert __m128d to double

Convert __m128d to double

By : red451
Date : March 29 2020, 07:55 AM
seems to work fine The counterpart of load would be store[ms, intel]. So in your case I'd guess (double precision, aligned pointer, regular store):
code :
_mm_store_pd(A, res); //A = res;
Returning a __m128d from MASM procedure to a C caller

Returning a __m128d from MASM procedure to a C caller

By : gd2398
Date : March 29 2020, 07:55 AM
I wish this helpful for you For educational purposes, I wrote up a version of your function that uses intrinsics:
code :
#include <immintrin.h>

extern "C" void AbsMax(__m128d* samples, int len, __m128d* pResult)
    __m128d min = _mm_setzero_pd();
    __m128d max = _mm_setzero_pd();
    while (len--)
        min = _mm_min_pd(min, *samples);
        max = _mm_max_pd(max, *samples);
    *pResult = _mm_max_pd(max, _mm_sub_pd(_mm_setzero_pd(), min));
; Listing generated by Microsoft (R) Optimizing Compiler Version 18.00.31101.0 
include listing.inc


samples$ = 8
len$ = 16
pResult$ = 24
AbsMax PROC                     ; COMDAT
    xorps   xmm3, xmm3
    movaps  xmm2, xmm3
    movaps  xmm1, xmm3
    test    edx, edx
    je  SHORT $LN6@AbsMax
    npad   3
    minpd   xmm2, XMMWORD PTR [rcx]
    maxpd   xmm1, XMMWORD PTR [rcx]
    lea rcx, QWORD PTR [rcx+16]
    dec edx
    jne SHORT $LL2@AbsMax
    subpd   xmm3, xmm2
    maxpd   xmm1, xmm3
    movaps  XMMWORD PTR [r8], xmm1
    ret 0
AbsMax  ENDP
Isn't __m128d aligned natively?

Isn't __m128d aligned natively?

By : Rajneesh Bhatt
Date : March 29 2020, 07:55 AM
I hope this helps you . __m128d is a type that assumes / requires / guarantees (to the compiler) 16-byte alignment1.
Casting a misaligned pointer to __m128d* and dereferencing it is undefined behaviour, and this is the expected result. Use _mm_loadu_pd if your data might not be aligned. (Or preferably, align your data with alignas(16) double a[bufferSize]; 2). ISO C++11 and later have portable syntax for aligning static and automatic storage (but not as easy for dynamic storage).
code :
typedef double __m128d_u 
       __attribute__ ((__vector_size__ (16), __may_alias__, __aligned__ (1)));
Related Posts Related Posts :
  • C++ on Vistual Studio with CMake error: manifest 'build.ninja' still dirty after 100 tries
  • Is there a way to automatically resolve an overloaded method via a template parameter?
  • Fastest way to find pair in a vector, remove it while iterating
  • error C2440: '=': cannot convert from 'const char *' to 'LPCWSTR'
  • Unable to call boost::clear_vertex while using listS for the vertex and edge lists
  • Decoding binary data from serial port
  • Pattern to Implement an OO interface to a C program written in an imperative style
  • CEPH + Librados++ is not returning consisten results
  • `LoadLibraryExW` triggers exception `0xC0000023` from `NtMapViewOfSection`
  • static_cast to a struct type to access all of its member variable
  • Forward declaration for boost::intrusive_ptr class to reduce compile time
  • How to use priority_queue with a non-static compare method of class instance?
  • Template parameters inside and outside class/struct
  • Determining prime number
  • How to resolve ambiguity between constructors taking std::string and std::vector
  • My program crashes when I try to change private values from an object
  • Unordered_map with custom class as key
  • Strict aliasing rules broken with templates and inheritance
  • C++ Derived Class Override Return Type
  • singly linked list c++ constructor, destructor and printing out
  • How to clone class with vector of unique_ptr to base class
  • error: no match for operator
  • std::vector doesnt accept my struct as template
  • selection of people's contours
  • how to fix the (Error using mexOpenCV) on matlab?
  • Is or was there a proposal for c++ to use the context for short enum values?
  • Fair assumptions about std::hash implementations
  • undefined reference to libusb using cyusb
  • Function returns null pointer instead of address
  • C++17 copy elision and object destruction
  • Input multiple strings via operator>> c++
  • Avoiding overflow boost container
  • How to Write a Lambda Wrapping a Function with Optional Return Value
  • Partial specialization with more template parameters
  • How to convert fixed size array to pointer on pointer array
  • Memory leak in const member constructor with tag dispatching
  • C++ function with a generic and optional class
  • Custom QGraphicsItem That Contains Child QGraphicsItems
  • Are There Restrictions on What can be Passed to auto Template Parameters?
  • Rotating line inside rectangle bounds
  • Why do I need dynamic memory allocation if I can just create an array?
  • How can I convert a text file into a form that MPI_Bcast can send?
  • How to get array of all `this` of an instance
  • Using pointers as parameters
  • Automatic type deduction with const_cast is not working
  • Why does std::is_rvalue_reference not do what it is advertised to do?
  • Function Template Specialization with Forward Declared Type
  • template deduction failed in vector
  • Is there a signed `sizeof` alternative in Qt
  • clarification on overloading the -> operator
  • QtConcurrent: why releaseThread and reserveThread cause deadlock?
  • Function receiving different value than passed
  • Can C++ close a '''fstream''' variable after '''.close()'''?
  • Is it necessary to overload operator in this specific case
  • Comparing an element of a string array with a string
  • how to dereference a pointer of a map of pointers to objects in c++
  • How recursive function control flow change for static variable?
  • SDL 2 blitting BMP File
  • Why does an extremely large value cause this code to repeat infinitely?
  • Function returning different value than what is in function body before return statement
  • shadow
    Privacy Policy - Terms - Contact Us © bighow.org