Address Literal Value Syntax ??

[RanOx]

Colleagues,

Is there a BAS Syntax for variable ADDRESS, rather than variable value.
eg.
Dim Fault_num_worst As Byte
Fault_num_worst_EE EData As Byte 123

temp_byte_0a = (Fault_num_worst - Fault_num_worst_EE) ;want ADDRESS, not variable VALUE

I know there is a VARPTR(variable) function, but this excutes code at run time, rather than loading at compile time.

I can use ASM "addlw" to load adresses (or difference in address in this example)
eg.
Asm ;do location maths.

Movf eerom_ptr_0b,W ;INDEX (relative EEROM location) > Accum.
Addlw Fault_num_worst - Fault_num_worst_EE ;add (difference between RAM address & EEROM address) to accum. (gets real RAM pointer in Accum.)
Movwf FSR ;Accum. > indirect addressing register
Movf temp_byte_0a,W; ;Byte (Read from EEROM) > Accum.
Movwf INDF ;Accum. > RAM @ pointer address (indirect addressing)

EndAsm


I also use the AT Syntax to define a Symbol, but do not want to do this whenever I need the address of a variable.
eg.

Dim Ptr_Input_mV As Byte At input_mV

;address of input_mV variable

Any ideas
Thanks
Alan.

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[Tim]

I will try and answer this

For starters lets identify the basics
Fault_num_worst will be a variable
Fault_num_worst_EE is a constant
VARPTR(variable) is a constant of the address of "variable" and is know at compile time. What might be the issue though is at what point in the compile cycle it becomes known. So it might not work exactly the way you want it.

I have to say I'm not 100% sure what you want to do so correct me if I go off track

I presume you want to know the address of a variable at compile time so you can do some maths on it during the compile. The only way I think you can do this is to set the address your self and tell Proton were that is. What you can also do is reserve memory so you can be sure its safe using the stack allocation system.

Dim MyVariable as Word at $100

The other solution is to use the variable name in say asm much the same as I think you are doing in the example.

HTH please point me right if I have your question wrong.

[RanOx]

Tim,
Thanks for your attention.

Fault_num_worst is a variable, but I wanted to use its ADDRESS, rather than its value.

I am using arrays of mixed (Byte & Word) variable types in RAM, which are initialised from EEROM values. They are later updated in EEROM, if changed.

I understood that there was no "compound" TYPE definition available in PDS, where I could define my own type (mix of Byte & Word), which could then be accessed by index (like a 2 dimensional array).

In PIC16, I was reading from EEROM[index] and writing to RAM[offset + index], inside a FOR/NEXT loop.

The index can be just the EEROM address (eg 24 .. 44).

However to write to the RAM (can't use CWRITE with PIC16), I had to know the RAM array "offset", which is the difference between RAM & EEROM address (for appropriate matching variables).

This was done with ASM, as partially ilustrated above.

However, I was wondering if there was a BAS Syntax for similar.

I have overcome (in PIC18 using 3.5.2.1), by using the AT format, as illustrated above. However, this requires an additional line per "requirement".

Previoulsy I had manually defined the address-values after examing ASM, but this can get "messy", if I add a variable lower in RAM, which changed addresses.

The VARPTR(var) adds run-time code, which was VERY tight in PIC16.

No big issue, if there is no syntax for using the address, so be-it.

Thanks
Alan.