5.5.2. NEON and VFP data types

Data type specifiers in NEON and VFP instructions consist of a letter indicating the type of data, usually followed by a number indicating the width. They are separated from the instruction mnemonic by a point. Table 5.5 shows the data types available in NEON instructions. Table 5.6 shows the data types available in VFP instructions.

Table 5.5. NEON data types

Unsigned integerU8U16U32U64
Signed integerS8S16S32S64
Integer of unspecified typeI8I16I32I64
Floating-point numbernot availableF16F32 (or F)not available
Polynomial over {0,1}P8P16not availablenot available

Table 5.6.  VFP data types

Unsigned integerU16U32not available
Signed integerS16S32not available
Floating-point numberF16F32 (or F)F64 (or D)

See Polynomial arithmetic over {0,1} for further information about operations on polynomials over {0,1}.

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


  • 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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