8.9 NEON data types

Most NEON instructions use a data type specifier to define the size and type of data that the instruction operates on.

Data type specifiers in NEON instructions usually consist of a letter indicating the type of data, followed by a number indicating the width. They are separated from the instruction mnemonic by a point.

The following table shows the data type specifiers available in NEON instructions:

Table 8-1 NEON data type specifiers

  8-bit 16-bit 32-bit 64-bit
Unsigned integer U8 U16 U32 U64
Signed integer S8 S16 S32 S64
Integer of unspecified type I8 I16 I32 I64
Floating-point number not available F16 F32 (or F) not available
Polynomial over {0,1} P8 P16 not available not available

The data type of the second (or only) operand is specified in the instruction.

Note:

  • Most instructions have a restricted range of permitted data types. See the instruction pages for details. However, the data type description is flexible:

    • If the description specifies I, you can also use S or U data types.

    • If only the data size is specified, you can specify a type (I, S, U, P or F).

    • If no data type is specified, you can specify a data type.

  • The F16 data type is only available on systems that implement the half-precision architecture extension.

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