UXTL, UXTL2
Unsigned extend long
This instruction copies each vector element
from the lower or upper half of the
source SIMD&FP register into a vector,
and writes the vector to the destination SIMD&FP
register.
The destination vector elements are twice
as long as the source vector elements.
The UXTL instruction extracts
vector elements from the lower half
of the source register. The UXTL2 instruction extracts
vector elements from the upper half
of the source register.
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.
If PSTATE.DIT is 1:
The execution time of this instruction is independent of:
The values of the data supplied in any of its registers.
The values of the NZCV flags.
The response of this instruction to asynchronous exceptions does not vary based on:
The values of the data supplied in any of its registers.
The values of the NZCV flags.
USHLL, USHLL2
0
1
0
1
1
1
1
0
!= 0000
0
0
0
1
0
1
0
0
1
UXTL{2} <Vd>.<Ta>, <Vn>.<Tb>
USHLL{2} <Vd>.<Ta>, <Vn>.<Tb>, #0
BitCount(immh) == 1
2
Is the second and upper half specifier. If present it causes the operation to be performed on the upper 64 bits of the registers holding the narrower elements, and is
Q
2
0
[absent]
1
[present]
<Vd>
Is the name of the SIMD&FP destination register, encoded in the "Rd" field.
<Ta>
Is an arrangement specifier,
immh
<Ta>
0001
8H
001x
4S
01xx
2D
1xxx
RESERVED
<Vn>
Is the name of the SIMD&FP source register, encoded in the "Rn" field.
<Tb>
Is an arrangement specifier,
immh
Q
<Tb>
0001
0
8B
0001
1
16B
001x
0
4H
001x
1
8H
01xx
0
2S
01xx
1
4S
1xxx
x
RESERVED