18.48 LDP (SIMD and FP)

Load Pair of SIMD and FP registers.

Syntax

LDP St1, St2, [Xn|SP], #imm ; 32-bit FP/SIMD registers, Post-index

LDP Dt1, Dt2, [Xn|SP], #imm ; 64-bit FP/SIMD registers, Post-index

LDP Qt1, Qt2, [Xn|SP], #imm ; 128-bit FP/SIMD registers, Post-index

LDP St1, St2, [Xn|SP, #imm]! ; 32-bit FP/SIMD registers, Pre-index

LDP Dt1, Dt2, [Xn|SP, #imm]! ; 64-bit FP/SIMD registers, Pre-index

LDP Qt1, Qt2, [Xn|SP, #imm]! ; 128-bit FP/SIMD registers, Pre-index

LDP St1, St2, [Xn|SP{, #imm}] ; 32-bit FP/SIMD registers, Signed offset

LDP Dt1, Dt2, [Xn|SP{, #imm}] ; 64-bit FP/SIMD registers, Signed offset

LDP Qt1, Qt2, [Xn|SP{, #imm}] ; 128-bit FP/SIMD registers, Signed offset

Where:

St1
Is the 32-bit name of the first SIMD and FP register to be transferred.
St2
Is the 32-bit name of the second SIMD and FP register to be transferred.
imm

Depends on the instruction variant:

32-bit FP/SIMD registers
Is the signed immediate byte offset, a multiple of 4 in the range -256 to 252.
64-bit FP/SIMD registers
Is the signed immediate byte offset, a multiple of 8 in the range -512 to 504.
128-bit FP/SIMD registers
Is the signed immediate byte offset, a multiple of 16 in the range -1024 to 1008.
Dt1
Is the 64-bit name of the first SIMD and FP register to be transferred.
Dt2
Is the 64-bit name of the second SIMD and FP register to be transferred.
Qt1
Is the 128-bit name of the first SIMD and FP register to be transferred.
Qt2
Is the 128-bit name of the second SIMD and FP register to be transferred.
Xn|SP
Is the 64-bit name of the general-purpose base register or stack pointer.

Usage

Load Pair of SIMD and FP registers. This instruction loads a pair of SIMD and FP registers from memory. The address that is used for the load is calculated from a base register value and an optional immediate offset.

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.

Note:

For information about the constrained unpredictable behavior of this instruction, see Architectural Constraints on UNPREDICTABLE behaviors in the Arm® Architecture Reference Manual Arm®v8, for Arm®v8‑A architecture profile, and particularly LDP (SIMD and FP).
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