TAL Reference Manual

Standard Functions

TAL Reference Manual—526371-001

14-9

Example of $BITLENGTH Function

In this example, $BITLENGTH returns the length, in bits, of one occurrence of structure

INT s_len; !Declare variable

STRUCT .s[0:3]; !Declare four occurrences of a

BEGIN ! structure

UNSIGNED(1) flags[0:15];

UNSIGNED(2) status;

BIT_FILLER 14;

END;

s_len := $BITLENGTH (s); !Return 32, the number of bits

! in one structure occurrence

$BITOFFSET Function

The $BITOFFSET function returns the number of bits from the address of the zeroth

structure occurrence to a structure data item.

variable

is the fully qualified identifier of a structure data item.

Usage Considerations

The zeroth structure occurrence has an offset of 0. For items other than substructure,

simple variable, array, or pointer declared within a structure, $BITOFFSET returns a 0.

When you qualify the identifier of

variable, you can use constant indexes but not

variable indexes; for example:

$BITOFFSET (struct1.subst[1].item) !1 is a constant index

To find the offset of an item in a structure, complete the structure before you use

$BITOFFSET.

You can use $BITOFFSET in LITERAL expressions and global initializations, because

it always returns a constant value.

$BITOFFSET (

variable )

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