TAL Programmer's Guide

Simple Variables by Data Type

Using Simple Variables

096254 Tandem Computers Incorporated 6–13

UNSIGNED

Simple Variables

When you declare an UNSIGNED simple variable, you must specify the width, in bits,

of the simple variable. Specify the width as a constant expression in the range 1

through 31, enclosed in parentheses, following the UNSIGNED keyword. The

constant expression can include LITERALs and DEFINEs:

UNSIGNED(5) bit_var; !Width of BIT_VAR is 5 bits

You cannot initialize UNSIGNED variables when you declare them.

Storage Allocation

The compiler packs consecutive UNSIGNED simple variables where possible. That is,

the compiler allocates the first UNSIGNED variable starting on a word boundary, and

then allocates each successive UNSIGNED variable in the remaining bits of the same

word as the preceding variable if:

The variable contains 1 to 16 bits and fits in the same word

The variable contains 17 to 31 bits and fits in the same word plus the next word

If an UNSIGNED variable does not fit in the same word or doubleword, the compiler

starts the variable on a word boundary.

STRING a;

UNSIGNED(8) d, e;

UNSIGNED(3) f;

UNSIGNED(5) g;

UNSIGNED(6) h;

UNSIGNED(25) j;

UNSIGNED(2) k;

FG H ?

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