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## TRN1

Transpose vectors (primary). This instruction reads corresponding even-numbered vector elements from the two source SIMD&FP registers, starting at zero, places each result into consecutive elements of a vector, and writes the vector to the destination SIMD&FP register. Vector elements from the first source register are placed into even-numbered elements of the destination vector, starting at zero, while vector elements from the second source register are placed into odd-numbered elements of the destination vector.

By using this instruction with TRN2, a 2 x 2 matrix can be transposed.

The following figure shows an example of the operation of TRN1 and TRN2 halfword operations where Q = 0.

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.

 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 Q 0 0 1 1 1 0 size 0 Rm 0 0 1 0 1 0 Rn Rd op

TRN1 <Vd>.<T>, <Vn>.<T>, <Vm>.<T>

```integer d = UInt(Rd);
integer n = UInt(Rn);
integer m = UInt(Rm);

if size:Q == '110' then UNDEFINED;
integer esize = 8 << UInt(size);
integer datasize = if Q == '1' then 128 else 64;
integer elements = datasize DIV esize;
integer part = UInt(op);
integer pairs = elements DIV 2;```

### Assembler Symbols

 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 0 RESERVED
11 1 2D
 Is the name of the first SIMD&FP source register, encoded in the "Rn" field.
 Is the name of the second SIMD&FP source register, encoded in the "Rm" field.

### Operation

```CheckFPAdvSIMDEnabled64();
bits(datasize) operand1 = V[n];
bits(datasize) operand2 = V[m];
bits(datasize) result;

for p = 0 to pairs-1
Elem[result, 2*p+0, esize] = Elem[operand1, 2*p+part, esize];
Elem[result, 2*p+1, esize] = Elem[operand2, 2*p+part, esize];

V[d] = result;```

### Operational information

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.