Function core::arch::x86::_mm_mpsadbw_epu8

pub unsafe fn _mm_mpsadbw_epu8(
    a: __m128i,
    b: __m128i,
    const IMM8: i32,
) -> __m128i

Available on (x86 or x86-64) and target feature sse4.1 and x86 only.

Subtracts 8-bit unsigned integer values and computes the absolute values of the differences to the corresponding bits in the destination. Then sums of the absolute differences are returned according to the bit fields in the immediate operand.

The following algorithm is performed:

i = IMM8[2] * 4
j = IMM8[1:0] * 4
for k := 0 to 7
    d0 = abs(a[i + k + 0] - b[j + 0])
    d1 = abs(a[i + k + 1] - b[j + 1])
    d2 = abs(a[i + k + 2] - b[j + 2])
    d3 = abs(a[i + k + 3] - b[j + 3])
    r[k] = d0 + d1 + d2 + d3

Arguments:

• a - A 128-bit vector of type __m128i.
• b - A 128-bit vector of type __m128i.
• IMM8 - An 8-bit immediate operand specifying how the absolute differences are to be calculated
  • Bit [2] specify the offset for operand a
  • Bits [1:0] specify the offset for operand b

Returns:

• A __m128i vector containing the sums of the sets of absolute differences between both operands.

Intel’s documentation