Index

REV

Reverse Bytes reverses the byte order in a register.

This instruction is used by the pseudo-instruction REV64.

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
sf 1 0 1 1 0 1 0 1 1 0 0 0 0 0 0 0 0 0 0 1 x Rn Rd
opc

32-bit (sf == 0 && opc == 10)

REV <Wd>, <Wn>

64-bit (sf == 1 && opc == 11)

REV <Xd>, <Xn>

if opc == '11' && sf == '0' then UNDEFINED;

integer d = UInt(Rd);
integer n = UInt(Rn);

constant integer datasize = 32 << UInt(sf);
constant integer container_size = 8 << UInt(opc);

Assembler Symbols

<Wd>

Is the 32-bit name of the general-purpose destination register, encoded in the "Rd" field.
<Wn>

Is the 32-bit name of the general-purpose source register, encoded in the "Rn" field.
<Xd>

Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field.
<Xn>

Is the 64-bit name of the general-purpose source register, encoded in the "Rn" field.

Operation

bits(datasize) operand = X[n, datasize];
bits(datasize) result;

constant integer containers = datasize DIV container_size;
for c = 0 to containers-1
    bits(container_size) container = Elem[operand, c, container_size];
    Elem[result, c, container_size] = Reverse(container, 8);

X[d, datasize] = result;

Operational information

If PSTATE.DIT is 1: