Conditional compare (register)
This instruction sets the value of the condition flags to the result of the comparison of two registers if the condition is TRUE, and an immediate value otherwise.
| 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 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 0 | Rm | cond | 0 | 0 | Rn | 0 | nzcv | ||||||||||||||
| op | S | o2 | o3 | ||||||||||||||||||||||||||||
let n : integer{} = UInt(Rn); let m : integer{} = UInt(Rm); let datasize : integer{} = 32 << UInt(sf); let condition : bits(4) = cond; var flags : bits(4) = nzcv;
| <Wn> |
Is the 32-bit name of the first general-purpose source register, encoded in the "Rn" field. |
| <Wm> |
Is the 32-bit name of the second general-purpose source register, encoded in the "Rm" field. |
| <nzcv> |
Is the flag bit specifier, an immediate in the range 0 to 15, giving the alternative state for the 4-bit NZCV condition flags, encoded in the "nzcv" field. |
| <Xn> |
Is the 64-bit name of the first general-purpose source register, encoded in the "Rn" field. |
| <Xm> |
Is the 64-bit name of the second general-purpose source register, encoded in the "Rm" field. |
if ConditionHolds(condition) then let operand1 : bits(datasize) = X{}(n); let operand2 : bits(datasize) = X{datasize}(m); (-, flags) = AddWithCarry{datasize}(operand1, NOT(operand2), '1'); end; PSTATE.[N,Z,C,V] = flags;
This instruction is a data-independent-time instruction as described in About PSTATE.DIT.
2026-03_rel 2026-03-26 20:48:11
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