>________________________________
> De: Jan-Erik Soderholm <jan-erik.soderholm@telia.com>
>Para: Microcontroller discussion list - Public. <piclist@mit.edu>=20
>Enviado: martes, 7 de agosto de 2012 17:50
>Asunto: Re: [PIC] GPasm question (probably gplink)
>=20
>
>
>John Coppens wrote 2012-08-07 22:20:
>> Hi all.
>>
>> I'm in the midst of a hobby project, which grew larger than expected
>> (don't they always).
>>
>> My project has several relocatable modules, and I noticed some strange
>> things. Say main.asm and moda.asm both have a section 'udata' and both
>> define several registers.
>>
>> Now, if I declare something like this in mod_a.asm:
>>
>> gpr0=A0=A0=A0 udata
>> reg1=A0=A0=A0 res=A0=A0=A0 5
>> reg2=A0=A0=A0 res=A0=A0=A0 1
>>
>> and then
>>
>> hdr=A0=A0=A0 equ=A0=A0=A0 reg1+0
>> len=A0=A0=A0 equ=A0=A0=A0 reg1+1
>> ...
>>
>
>I do not think you can mix RES symbols with EQU symbols that way.
>They are not of the same "type" so to speak.
>
>MPASM will give an error on this (even without "+0/1") :
>
>"Operand contains unresolvable labels or is too complex"
>
>Note that MPASM expects to know the value of the EQU (and SET)
>symbols during assembly-time, the RES symbols are not known
>until link-time (MPLINK or other linker). The value of reg1
>is not important for MPASM (and probably GPASM). It's just
>a name it passes over to MPLINK (or GPLINK).
>
>But, a single UDATA section is always continus, so you can do:
>
>myvars=A0 =A0=A0=A0udata
>reg1_hdr=A0=A0=A0res=A0 =A0 1
>reg1_len=A0=A0=A0res=A0 =A0 1
>reg1_rest=A0 res=A0 =A0 3
>reg2=A0 =A0 =A0=A0=A0res=A0 =A0 1
>

My 2 cents here.=A0 It has been a while since I don't code fluently in asse=
mbly but If I remember correctly I think he could also use overlay data, so=
 he can place reg1_hdr, reg1_len and reg1_rest starting at the same locatio=
n as reg1=20


There were some things to do with the linker like declaring a section and t=
hen declaring both vars in the same section or something like that.=A0 As I=
 said its been a while and I forgot the details.=A0 I could dig more deeply=
 in my older source codes if needed.

Mauricio

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