SP_EL1

Holds the stack pointer associated with EL1. When executing at EL1, the value of SPSel.SP determines the current stack pointer:

Configuration

Attributes

Field descriptions

Bits [63:0]

SPSel.SP	Current stack pointer
0b0	SP_EL0
0b1	SP_EL1

Accessing SP_EL1

This accessibility information only applies to accesses using the MRS or MSR instructions.

When the value of SPSel.SP is 1, this register is also accessible at EL1 as the current stack pointer.

Note

When the value of SPSel.SP is 0, SP_EL0 is used as the current stack pointer at all Exception levels.

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

MRS <Xt>, SP_EL1

op0	op1	CRn	CRm	op2
0b11	0b100	0b0100	0b0001	0b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() IN {'1x1'} then X[t, 64] = NVMem[0x240]; elsif EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then X[t, 64] = SP_EL1; elsif PSTATE.EL == EL3 then X[t, 64] = SP_EL1;

MSR SP_EL1, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b100	0b0100	0b0001	0b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() IN {'1x1'} then NVMem[0x240] = X[t, 64]; elsif EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then SP_EL1 = X[t, 64]; elsif PSTATE.EL == EL3 then SP_EL1 = X[t, 64];

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Stack pointer
Stack pointer

SP_EL1, Stack Pointer (EL1)