REV64

Reverse elements in 64-bit doublewords (vector). This instruction reverses the order of 8-bit, 16-bit, or 32-bit elements in each doubleword of the vector in the source SIMD&FP register, places the results into a vector, and writes the vector to the destination SIMD&FP 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.

313029282726252423222120191817161514131211109876543210
0Q001110size100000000010RnRd
Uo0

REV64 <Vd>.<T>, <Vn>.<T>

integer d = UInt(Rd); integer n = UInt(Rn); constant integer esize = 8 << UInt(size); constant integer datasize = 64 << UInt(Q); constant integer csize = 64 >> UInt(o0:U); if csize <= esize then UNDEFINED; integer containers = datasize DIV csize;

Assembler Symbols

<Vd>

Is the name of the SIMD&FP destination register, encoded in the "Rd" field.

<T>

Is an arrangement specifier, encoded in size:Q:

size Q <T>
00 0 8B
00 1 16B
01 0 4H
01 1 8H
10 0 2S
10 1 4S
11 x RESERVED
<Vn>

Is the name of the SIMD&FP source register, encoded in the "Rn" field.

Operation

CheckFPAdvSIMDEnabled64(); bits(datasize) operand = V[n, datasize]; bits(datasize) result; for c = 0 to containers-1 bits(csize) container = Elem[operand, c, csize]; Elem[result, c, csize] = Reverse(container, esize); V[d, datasize] = result;

Operational information

If PSTATE.DIT is 1:


Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46

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