SP_EL0

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SP_EL0, Stack Pointer (EL0)

Purpose

Holds the stack pointer associated with EL0. At higher Exception levels, this is used as the current stack pointer when the value of SPSel.SP is 0.

Configuration

This register is present only when FEAT_AA64 is implemented. Otherwise, direct accesses to SP_EL0 are UNDEFINED.

Attributes

Field descriptions

StackPointer, bits [63:0]

Accessing SP_EL0

When the value of PSTATE.SP is 0, this register is accessible at all Exception levels as the current stack pointer.

Accesses to this register use the following encodings in the System register encoding space:

MRS <Xt>, SP_EL0

op0	op1	CRn	CRm	op2
0b11	0b000	0b0100	0b0001	0b000

if !IsFeatureImplemented(FEAT_AA64) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if PSTATE.SP == '0' then Undefined(); else X{64}(t) = SP_EL0(); end; elsif PSTATE.EL == EL2 then if PSTATE.SP == '0' then Undefined(); else X{64}(t) = SP_EL0(); end; elsif PSTATE.EL == EL3 then if PSTATE.SP == '0' then Undefined(); else X{64}(t) = SP_EL0(); end; end;

MSR SP_EL0, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b000	0b0100	0b0001	0b000

if !IsFeatureImplemented(FEAT_AA64) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if PSTATE.SP == '0' then Undefined(); else SP_EL0() = X{64}(t); end; elsif PSTATE.EL == EL2 then if PSTATE.SP == '0' then Undefined(); else SP_EL0() = X{64}(t); end; elsif PSTATE.EL == EL3 then if PSTATE.SP == '0' then Undefined(); else SP_EL0() = X{64}(t); end; end;

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StackPointer
StackPointer