Floating-point conditional select (scalar)
This instruction allows the SIMD&FP destination register to take the value from either one or the other of two SIMD&FP source registers. If the condition passes, the first SIMD&FP source register value is taken, otherwise the second SIMD&FP source register value is taken.
Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.
| 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 |
| 0 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | ftype | 1 | Rm | cond | 1 | 1 | Rn | Rd | ||||||||||||||||
| M | S | ||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_FP) then EndOfDecode(Decode_UNDEF); if ftype == '10' then EndOfDecode(Decode_UNDEF); if ftype == '11' && !IsFeatureImplemented(FEAT_FP16) then EndOfDecode(Decode_UNDEF); constant integer d = UInt(Rd); constant integer n = UInt(Rn); constant integer m = UInt(Rm); constant integer datasize = 8 << UInt(ftype EOR '10'); constant bits(4) condition = cond;
| <Hd> |
Is the 16-bit name of the SIMD&FP destination register, encoded in the "Rd" field. |
| <Hn> |
Is the 16-bit name of the first SIMD&FP source register, encoded in the "Rn" field. |
| <Hm> |
Is the 16-bit name of the second SIMD&FP source register, encoded in the "Rm" field. |
| <Sd> |
Is the 32-bit name of the SIMD&FP destination register, encoded in the "Rd" field. |
| <Sn> |
Is the 32-bit name of the first SIMD&FP source register, encoded in the "Rn" field. |
| <Sm> |
Is the 32-bit name of the second SIMD&FP source register, encoded in the "Rm" field. |
| <Dd> |
Is the 64-bit name of the SIMD&FP destination register, encoded in the "Rd" field. |
| <Dn> |
Is the 64-bit name of the first SIMD&FP source register, encoded in the "Rn" field. |
| <Dm> |
Is the 64-bit name of the second SIMD&FP source register, encoded in the "Rm" field. |
AArch64.CheckFPEnabled(); bits(datasize) result; constant boolean condition_holds = ConditionHolds(condition); result = if condition_holds then V[n, datasize] else V[m, datasize]; V[d, datasize] = result;
This instruction is a data-independent-time instruction as described in About PSTATE.DIT.
Version 2025.09 — Copyright © 2010-2025 Arm Limited or its affiliates.
This site is provided as a community resource and is NOT affiliated with nor endorsed by Arm Limited.