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 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
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