(old) | htmldiff from- | (new) |
Count Leading Sign bits counts the number of leading bits of the source register that have the same value as the most significant bit of the register, and writes the result to the destination register. This count does not include the most significant bit of the source 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 | 0 | 1 | Rn | Rd | ||||||||
op |
integer d = UInt(Rd);
integer n = UInt(Rn);
integer datasize = if sf == '1' then 64 else 32;CountOp opcode = if op == '0' then CountOp_CLZ else CountOp_CLS;
<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. |
integer result;
bits(datasize) operand1 = X[n];
result =if opcode == CountOp_CLZ then
result = CountLeadingZeroBits(operand1);
else
result = CountLeadingSignBits(operand1);
X[d] = result<datasize-1:0>;
If PSTATE.DIT is 1:
Internal version only: isa v32.13, AdvSIMD v29.05, pseudocode v2020-12, sve v2020-12
; Build timestamp: 2020-12-16T162020-12-16T14:5341
Copyright © 2010-2020 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.
(old) | htmldiff from- | (new) |