EQU and CBLOCK and DEFINE

Hi, I am confused with these 2.
The Equ is used for defining a register of general purpose. The Cblock is for a consecutive group of varialbes, and Define is for a pin of a port.
They are all confusing. Could someone please give me a clearer explanation?
Thanks alot.

equ- Define Assembler Constant.
four equ 4 ;assigned the numeric value of 4 to label four

cblock-Define a Block of Constants. ;Define a list of named constants. Each <label> is assigned a value of one higher than the previous <label>. The purpose of this directive is to assign address offsets to many labels. The list of names end when an endc directive is encountered.

#define-Define a Text Substitution Label ;This directive defines a text substitution string. Wherever <name> is encountered in the assembly code, <string> will be substituted.

Strongly recomend it to read the MPASM Assembler Help.
This are cut's from the HELP manual.

STEVE

Yeah, thanks csaba911. If I need a register to store a value, and this value can be changed over the program, and I see people use EQU. This is certainly not a constant, as it can be changed.
In assembly, I dont see a clear barrier between constant and varialbe, unlike in Java:
final private int i = constant i
private int i = variable i

You'll find that your code contains constant values that reappear over and over. In these cases, you can greatly improve the readability of your code by using constants.

If I need a register to store a value, and this value can be changed over the program, and I see people use EQU. This is certainly not a constant, as it can be changed.

Click to expand...

Can you change the memory location once is ben set ?!
The location of the register is constant !
The value here is CONSTANT
You can write If you have 30 mem address, thing can get out of hand easy if you try to remember all the mem location by their addres.

#define control 0x19,7
control is = address 0x19 bit 7

Maybe I can't explane to you, but at least I know how to use them.

STEVE