# __m64_pavgsub2

Visual Studio 2010

Microsoft Specific

Emits the 2-byte form of the Parallel Average Subtract (pavgsub2) instruction.

```__m64 __m64_pavgsub2(
__m64 a,
__m64 b
);
```

## Parameters

[in] a

An __m64 union containing an array of four unsigned short integers, which are subtracted from.

[in] b

An __m64 union containing an array of four unsigned short integers, which are subtracted.

## Return Value

An __m64 union containing the array of results of (a[i]-b[i])/2 interpreted as 16-bit signed integers.

Intrinsic

Architecture

__m64_pavgsub2

IPF

## Remarks

The numbers in the input array b are subtracted from the numbers in the input array a. The result is an __m64 union containing an array of unsigned short integers with the result of (a[i] – b[i])/2, where i numbers the four unsigned integers in the source arrays. If fractional, the result of each average is rounded to the nearest odd integer.

## Example

```// pavgsub2.cpp
// processor: IPF
#include <stdio.h>
#include <intrin.h>

#pragma intrinsic(__m64_pavgsub2)

void print4u(unsigned __int16* ia)
{
printf_s("{ %8u, %8u, %8u, %8u }\n", ia[0], ia[1], ia[2], ia[3] );
}

void print4(__int16* ia)
{
printf_s("{ %8d, %8d, %8d, %8d }\n", ia[0], ia[1], ia[2], ia[3] );
}

int main()
{
__m64 m, n, result;
unsigned __int16 ra[4], i;
unsigned __int16 ma[4] = { 10, 100, 70, 10000 };
unsigned __int16 na[4] = { 1, 95, 50,   5000 };

for (i = 0; i < 4; i++)
{
m.m64_u16[i] = ma[i];
n.m64_u16[i] = na[i];
}

printf_s("a: \n");
print4u(ma);
printf_s("b: \n");
print4u(na);
printf_s("\n");

result = __m64_pavgsub2(m, n);

printf_s("Parallel Average Subtract (a[]-b[])/2 : \n");
print4(result.m64_i16);
printf_s("\n");

result = __m64_pavgsub2(n, m);

printf_s("Parallel Average Subtract (b[]-a[])/2 : \n");
print4(result.m64_i16);
printf_s("\n");

}
```
```a:
{       10,      100,       70,    10000 }
b:
{        1,       95,       50,     5000 }

Parallel Average Subtract (a[]-b[])/2 :
{        5,        3,       10,     2500 }

Parallel Average Subtract (b[]-a[])/2 :
{       -5,       -3,      -10,    -2500 }```