vpopcntd

Pseudocode Operation

for i in 0 to 1 do
  count ← 0
  doubleword ← vB[i*64 : i*64+63]
  for j in 0 to 63 do
    if doubleword[j] = 1 then
      count ← count + 1
  vD[i*64 : i*64+63] ← count

Programming Note

The vpopcntd instruction is useful for counting the number of set bits in each 64-bit element of a vector. Ensure that the Vector Facility (MSR.VEC) is enabled before using this instruction; otherwise, it will raise an exception. This instruction operates on two doublewords per vector register, and results are stored in the corresponding positions of the destination vector.

Example