(
n1 n2 "<spaces>name" --
n3 )
Skip leading space delimiters. Parse
name delimited
by a space. Create a definition for
name with the
execution semantics defined below. Return
n3 =
n1 +
n2 where
n1 is the offset
in the data structure before
+FIELD executes, and
n2 is the size of the data to be added to the data
structure.
n1 and
n2 are in address units.
name Execution:
(
addr1 --
addr2 )
Add
n1 to
addr1 giving
addr2.
Rationale:
+FIELD is not required to align items. This is
deliberate and allows the construction of unaligned data
structures for communication with external elements such
as a hardware register map or protocol packet.
Field alignment has been left to the appropriate
xFIELD: definition.
Implementation:
Create a new field within a structure definition
of size n bytes.
: +FIELD
\ n <"name"> -- ; Exec: addr -- 'addr
CREATE OVER , +
DOES> @ +
;