CLZ

Count Leading Zeros counts the number of consecutive binary zero bits, starting from the most significant bit in the source register, and places the count in the destination register.

313029282726252423222120191817161514131211109876543210
sf101101011000000000100RnRd
op

32-bit (sf == 0)

CLZ <Wd>, <Wn>

64-bit (sf == 1)

CLZ <Xd>, <Xn>

integer d = UInt(Rd); integer n = UInt(Rn); integer datasize = if sf == '1' then 64 else 32;

Assembler Symbols

<Wd>

Is the 32-bit name of the general-purpose destination register, encoded in the "Rd" field.

<Wn>

Is the 32-bit name of the general-purpose source register, encoded in the "Rn" field.

<Xd>

Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field.

<Xn>

Is the 64-bit name of the general-purpose source register, encoded in the "Rn" field.

Operation

integer result; bits(datasize) operand1 = X[n, datasize]; result = CountLeadingZeroBits(operand1); X[d, datasize] = result<datasize-1:0>;

Operational information

If PSTATE.DIT is 1:


Internal version only: isa v33.53, AdvSIMD v29.11, pseudocode v2022-09_rel, sve v2022-09_rel ; Build timestamp: 2022-09-30T16:37

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