89 lines
1.8 KiB
C
89 lines
1.8 KiB
C
/**
|
|
* @license Apache-2.0
|
|
*
|
|
* Copyright (c) 2020 The Stdlib Authors.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#include "stdlib/blas/base/sswap.h"
|
|
|
|
/**
|
|
* Interchanges two single-precision floating-point vectors.
|
|
*
|
|
* @param N number of elements to swap
|
|
* @param X first input array
|
|
* @param strideX X stride length
|
|
* @param Y second input array
|
|
* @param strideY Y stride length
|
|
*/
|
|
void c_sswap( const int N, float *X, const int strideX, float *Y, const int strideY ) {
|
|
float tmp;
|
|
int ix;
|
|
int iy;
|
|
int i;
|
|
int m;
|
|
|
|
if ( N <= 0 ) {
|
|
return;
|
|
}
|
|
// If both strides are equal to `1`, use unrolled loops...
|
|
if ( strideX == 1 && strideY == 1 ) {
|
|
m = N % 3;
|
|
|
|
// If we have a remainder, do a clean-up loop...
|
|
if ( m > 0 ) {
|
|
for ( i = 0; i < m; i++ ) {
|
|
tmp = X[ i ];
|
|
X[ i ] = Y[ i ];
|
|
Y[ i ] = tmp;
|
|
}
|
|
if ( N < 3 ) {
|
|
return;
|
|
}
|
|
}
|
|
for ( i = m; i < N; i += 3 ) {
|
|
tmp = X[ i ];
|
|
X[ i ] = Y[ i ];
|
|
Y[ i ] = tmp;
|
|
|
|
tmp = X[ i+1 ];
|
|
X[ i+1 ] = Y[ i+1 ];
|
|
Y[ i+1 ] = tmp;
|
|
|
|
tmp = X[ i+2 ];
|
|
X[ i+2 ] = Y[ i+2 ];
|
|
Y[ i+2 ] = tmp;
|
|
}
|
|
return;
|
|
}
|
|
if ( strideX < 0 ) {
|
|
ix = (1-N) * strideX;
|
|
} else {
|
|
ix = 0;
|
|
}
|
|
if ( strideY < 0 ) {
|
|
iy = (1-N) * strideY;
|
|
} else {
|
|
iy = 0;
|
|
}
|
|
for ( i = 0; i < N; i++ ) {
|
|
tmp = X[ ix ];
|
|
X[ ix ] = Y[ iy ];
|
|
Y[ iy ] = tmp;
|
|
ix += strideX;
|
|
iy += strideY;
|
|
}
|
|
return;
|
|
}
|