Count Trailing Zeros counts the number of consecutive binary zero bits, starting from the least significant bit in the source register, and places the count in the destination register.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| sf | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | Rn | Rd | ||||||||
| S | opcode2 | opcode | |||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_CSSC) then UNDEFINED; constant integer datasize = 32 << UInt(sf); integer d = UInt(Rd); integer n = UInt(Rn);
| <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. |
bits(datasize) operand1 = X[n, datasize]; integer result = CountLeadingZeroBits(BitReverse(operand1)); X[d, datasize] = result<datasize-1:0>;
If PSTATE.DIT is 1:
Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45
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