ARM VERSION 1.2 - Manual (Page 293)

Directives Reference
ARM DUI 0068B Copyright © 2000, 2001 ARM Limited. All rights reserved. 7-11
7.2.7 DN and SN
The DN directive defines a name for a specified double-precision VFP register. The
names d0-d15 and D0-D15 are predefined.
The SN directive defines a name for a specified single-precision VFP register. The names
s0-s31 and S0-S31 are predefined.
Syntax
name DN expr
name SN expr
where:
name is the name to be assigned to the VFP register. name cannot be the same as
any of the predefined names listed in Predefined register and coprocessor
names on page 3-9.
expr evaluates to a double-precision VFP register number from 0 to 15, or a
single-precision VFP register number from 0 to 31 as appropriate.
Usage
Use DN or SN to allocate convenient names to VFP 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 (see VFP directives and vector
notation on page 6-40).
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