DN, and SN

ARM Compiler toolchain v5.02 for µVision Assembler Reference

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DN, and SN

The DN directive defines a name for a specified 64-bit extension register.

The SN directive defines a name for a specified single-precision VFP register.

Syntax

name directive expr{.type}

where:

directive

is DN or SN.

name

is the name to be assigned to the extension register. name cannot be the same as any of the predefined names.

expr

Can be:

an expression that evaluates to a number in the range:
- 0-15 if you are using DN in VFPv2
- 0-31 otherwise.
a predefined register name, or a register name that has already been defined in a previous directive.

type

is any or VFP datatype.

type is Extended notation.

Usage

Use DN or SN to allocate convenient names to extension registers, to help you to remember what you use each one for.

Note

Avoid conflicting uses of the same register under different names.

You cannot specify a vector length in a DN or SN directive.

Examples

energy  DN  6   ; defines energy as a symbol for
                ; VFP double-precision register 6
mass    SN  16  ; defines mass as a symbol for
                ; VFP single-precision register 16

Extended notation example

varA    DN      d1.U16
varB    DN      d2.U16
varC    DN      d3.U16
        VADD    varA,varB,varC       ; VADD.U16 d1,d2,d3

DN, and SN

DN, and SN

Syntax

Usage

Note

Examples

Extended notation example

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