Send text (addresing problem assembler)

brian4 · ‎2007-04-16

Posted on April 16, 2007 at 11:09

brian4 · ‎2007-04-16

Posted on April 16, 2007 at 09:14

Hi all

Having a bad day, simple problem but I just cant figure out the syntax

I have some text messages I am sending out on a pin, I now have the TX pin routine working.

In Assembler I want to write a routine to send each string. The strings are stored as Mess01, 02 etc.

I assume I use A,([ptr.w],X) to read the string in where X = Character position

In ROM segment I have

.Mess01

STRING ''Power On Reset''

DC.B $0D

.Mess02

STRING ''Test In Progress''

DC.B $0D

My simple question is how do I read the location (16 bit) of Mess01 or 02 etc and save that in ptr.w location

Not done much with index addressing before.

Re Brian

wolfgang2399 · ‎2007-04-16

Posted on April 16, 2007 at 10:56

Hi Brian,

it seems not to exist a fixed rule. The code to use depends on your compiler.

The original ST asm7 works with the code (not tested!)

---------------------

LD A,#Mess01.l

LD {ptr+1},A ; curly brackets!!

LD A,#Mess01.h

LD ptr,A

---------------------

while my compiler needs the syntax

---------------------

LD A,#LOW(Mess01)

LD ptr:1,A

LD A,#HIGH(Mess01)

LD ptr,A

---------------------

Regards

WoRo

brian4 · ‎2007-04-16

Posted on April 16, 2007 at 11:09

Thanks for that

Just found the .h & .l in a Link USER manual PDF and I have just typed the same as you suggested, all works ok.

One other slight funny

In my data.asm file I have defineed

ptr.w 1

However if in my data.inc file I state EXTERN ptr.w I get and error?

Error 54: Can't match Addressing mode ' ld A,([ptr.w],X)

but if I state EXTERN ptr.b I get no errors and all works.

Re Brian