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# CurrentEL, Current Exception Level

The CurrentEL characteristics are:

## Purpose

Holds the current Exception level.

## Configuration

Some or all RW fields of this register have defined reset values. These apply only if the PE resets into an Exception level that is using AArch64. Otherwise, RW fields in this register reset to architecturally UNKNOWN values.

## Attributes

CurrentEL is a 64-bit register.

## Field descriptions

The CurrentEL bit assignments are:

63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32
RES0
RES0 | EL | RES0
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

#### Bits [63:4]

Reserved, RES0.

#### EL, bits [3:2]

Current Exception level. Possible values of this field are:

EL | Meaning
--- | ---
0b00 | EL0
0b01 | EL1
0b10 | EL2
0b11 | EL3

When the HCR_EL2.NV bit is 1, EL1 read accesses to the CurrentEL register return the value of 0b10 in this field.

This field resets to the highest implemented Exception Level.

#### Bits [1:0]

Reserved, RES0.

## Accessing the CurrentEL

Accesses to this register use the following encodings:

#### MRS <Xt>, CurrentEL

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b11 | 0b000 | 0b0100 | 0b0010 | 0b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.NV == '1' then return Zeros(60):'10':Zeros(2); else return Zeros(60):PSTATE.EL:Zeros(2); elsif PSTATE.EL == EL2 then return Zeros(60):PSTATE.EL:Zeros(2); elsif PSTATE.EL == EL3 then return Zeros(60):PSTATE.EL:Zeros(2);

AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

15/04/2019 16:47; 8c23526ba8a13a72aada4137daf3e3977b49036e

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