Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
Export (0) Print
Expand All
Expand Minimize
Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here.


Microsoft Specific

Emits the Streaming SIMD Extensions 4 (SSE4) instruction roundps. This instruction rounds the parameter down.

__m128 _mm_floor_ps( 
   __m128 a

[in] a

A 128-bit parameter that contains four 32-bit floating point values.

The result can be expressed with the following equations:

r0 := FLOOR(a0)
r1 := FLOOR(a1)
r2 := FLOOR(a2)
r3 := FLOOR(a3)




x86, x64

Header file <smmintrin.h>

r0-r3 and a0-a3 are the sequentially ordered 32-bit components of return value r and parameter a. r0 and a0 denote the least significant 32 bits.

This function is implemented as a macro that invokes _mm_round_ps.

Before you use this intrinsic, software must ensure that the processor supports the instruction.

#include <stdio.h>
#include <smmintrin.h>

int main ()
    __m128 a;

    a.m128_f32[0] = 0.0625;
    a.m128_f32[1] = -3.25;
    a.m128_f32[2] = 100.125;
    a.m128_f32[3] = -0.5;

    __m128 res = _mm_floor_ps(a);

    printf_s("Original a: %f\t%f\t%f\t%f\n",
                a.m128_f32[0], a.m128_f32[1], a.m128_f32[2], a.m128_f32[3]);
    printf_s("Result res: %f\t%f\t%f\t%f\n",
                res.m128_f32[0], res.m128_f32[1], res.m128_f32[2], res.m128_f32[3]);

    return 0;
Original a: 0.062500 -3.250000 100.125000 -0.500000 Result res: 0.000000 -4.000000 100.000000 -1.000000

Community Additions

© 2015 Microsoft