__m64_pavgsub1
Microsoft Specific
Emits the 1-byte form of the Parallel Average Subtract (pavgsub1) instruction.
__m64 __m64_pavgsub1(
__m64 a,
__m64 b
);
Parameters
- [in] a
An array of 8 bytes interpreted as unsigned 1-byte integers to be subtracted from.
- [in] b
An array of 8 bytes interpreted as unsigned 1-byte integers to subtract.
Return Value
An __m64 union containing the array of results of (a[i]-b[i])/2 interpreted as signed 8-bit integers.
Requirements
| Intrinsic | Architecture |
|---|---|
__m64_pavgsub1 |
IPF |
Header file <intrin.h>
Remarks
The instruction computes (a[i]-b[i])/2 for each byte i of a and b. Each byte in the array is treated as an 8-bit unsigned integer. If fractional, the result in each byte is rounded to the nearest odd integer.
Example
// pavgsub1.cpp
// processor: IPF
#include <stdio.h>
#include <intrin.h>
#pragma intrinsic(__m64_pavgsub1)
void print8(__int8* ia)
{
printf_s("{ %4d, %4d, %4d, %4d, %4d, %4d, %4d, %4d}\n",
ia[0], ia[1], ia[2], ia[3], ia[4], ia[5], ia[6], ia[7] );
}
void print8u(unsigned __int8* ia)
{
printf_s("{ %4u, %4u, %4u, %4u, %4u, %4u, %4u, %4u }\n",
ia[0], ia[1], ia[2], ia[3], ia[4], ia[5], ia[6], ia[7] );
}
int main()
{
__m64 m, n, result;
__int8 ra[8], i;
unsigned __int8 ma[8] = { 1, 5, 255, 255, 8, 8, 8, 8 };
unsigned __int8 na[8] = { 5, 1, 1, 0, 2, 1, 0, 8 };
for (i = 0; i < 8; i++)
{
m.m64_u8[i] = ma[i];
n.m64_u8[i] = na[i];
}
printf_s("a: \n");
print8u(ma);
printf_s("b: \n");
print8u(na);
printf_s("\n");
result = __m64_pavgsub1(m, n);
printf_s("Parallel Average Subtract (a[]-b[])/2 : \n");
print8(result.m64_i8);
printf_s("\n");
result = __m64_pavgsub1(n, m);
printf_s("Parallel Average Subtract (b[]-a[])/2 : \n");
print8(result.m64_i8);
printf_s("\n");
}
Output
a:
{ 1, 5, 255, 255, 8, 8, 8, 8 }
b:
{ 5, 1, 1, 0, 2, 1, 0, 8 }
Parallel Average Subtract (a[]-b[])/2 :
{ -2, 2, 127, 127, 3, 3, 4, 0}
Parallel Average Subtract (b[]-a[])/2 :
{ 2, -2, -127, -127, -3, -3, -4, 0}