ARM VERSION 1.2 - Manual (Page 297)

Directives Reference
ARM DUI 0068B Copyright © 2000, 2001 ARM Limited. All rights reserved. 7-15
7.3.2 MAP
The MAP directive sets the origin of a storage map to a specified address. The
storage-map location counter, {VAR} , is set to the same address. ^ is a synonym for MAP .
Syntax
MAP expr{,base-register}
where:
expr is a numeric or program-relative expression:
• If base-register is not specified, expr evaluates to the address
where the storage map starts. The storage map location counter is
set to this address.
• If expr is program-relative, you must have defined the label before
you use it in the map. The map requires the definition of the label
during the first pass of the assembler.
base-register
specifies a register. If base-register is specified, the address where the
storage map starts is the sum of expr , and the value in base-register at
runtime.
Usage
Use the MAP directive in combination with the FIELD directive to describe a storage map.
Specify base-register to define register-relative labels. The base register becomes
implicit in all labels defined by following FIELD directives, until the next MAP directive.
The register-relative labels can be used in load and store instructions. See FIELD on
page 7-16 for an example.
The MAP directive can be used any number of times to define multiple storage maps.
The {VAR} counter is set to zero before the first MAP directive is used.
Examples
MAP 0,r9
MAP 0xff,r9