27220 Parallax Inc, 27220 Datasheet - Page 222

• Manufacturer Part Number: 27220
• Description: BOOK STAMPWORKS
• Manufacturer: Parallax Inc

Specifications of 27220

• Accessory Type: Booklet
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: StampWorks
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Not applicable / Not applicable

With just a little more effort we can have the same array and have aliases to
elements in it. Here’s how:
The variable called
This section of code does exactly the same thing:
This works because the BASIC Stamp variable space can be treated as an implicit
array. The size of the elements will depend on the variable one selects as the base.
The other key to this trick is that the compiler declares variables of the same type in
the order they appear in your listing. In this example the variables colors and red
occupy the same space in memory, with green and blue following in that order.
Overlay Variables to Save Code
Let’s say you have two sets of byte-sized flag variables. You could define them like
this:
This works fine, of course, but you can save a bit of code and execution speed by
aliasing these bytes to a single Word variable like this:
colors
red
green
blue
flags0
flags1
flags
flags0
flags1
colors(0) = 50
colors(1) = 10
colors(2) = 35
red = 50
green = 10
blue = 35
colors
VAR
VAR
VAR
VAR
VAR
VAR
VAR
VAR
VAR
can still be treated like an array:
Byte
colors
Byte
Byte
Byte
Byte
Word
flags.BYTE0
flags.BYTE1