Page 370 - ARM 64 Bit Assembly Language
P. 370
360 Chapter 10
10.6.8.1 Syntax
cl(s|z) Vd.T, Vm.T
cnt Vd.Tn, Vm.Tn
• T must be 8b, 16b, 4h, 8h, 2s,or 4s.
• Tn must be 8b or 16b.
10.6.8.2 Operations
Name Effect Description
cls n ← # of elements Count the number of consecutive
for 0 ≤ i< n) do bits that are the same as the sign bit
Vd[i]← for each element in Fm, and store the
leading_sign_bits(Vm[i]) counts in the corresponding elements
end for of Fd.
clz n ← # of elements Count the number of leading zero bits
for 0 ≤ i< n) do for each element in Fm, and store the
Vd[i]← counts in the corresponding elements
leading_zero_bits(Vm[i]) of Fd.
end for
cnt n ← # of elements Count the number of bits in Fm that
for 0 ≤ i< n) do are set to one, and store the counts in
Vd[i]← the corresponding elements of Fd.
count_one_bits(Vm[i])
end for
10.6.8.3 Examples
1 cls v1.4s,v6.4s // Count leading sign bits
2 cnt v0.8b,v4.8b // Count bits that are 1
10.6.9 Scalar saturating operations
The following instructions perform basic saturating operations on scalars:
qadd Scalar saturating add,
qsub Scalar saturating subtract,
qdmulh Scalar saturating multiply (high half), and
qshl Scalar saturating shift left.
