Permanently Undefined generates an Undefined Instruction exception (ESR_ELx.EC = 0b000000). The encodings for UDF used in this section are defined as permanently undefined in the Armv8-A architecture.
| 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 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | imm16 | |||||||||||||||
UDF #<imm>
// The imm16 field is ignored by hardware. UNDEFINED;
| <imm> |
is a 16-bit unsigned immediate, in the range 0 to 65535, encoded in the "imm16" field. The PE ignores the value of this constant. |
Internal version only: isa v32.13, AdvSIMD v29.04, pseudocode morello-2022-01_rc2, capabilities morello-2022-01_rc2 ; Build timestamp: 2022-01-11T11:23
Copyright © 2010-2022 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.