Post by thread:[PIC]: MPASM include files

Dear Pic'ers, I've found lots of very clever little PIC assembler fragments on http://piclist.org/ . Now I'm looking for advice on how to structure an entire project. I'm getting unexpected errors from MPASM now that I've split up my project into several files. Maybe I just need to learn the ``Assembly Way'' of doing things. I'm used to the ``C Way'' of breaking up a program into several files, as explained in the C FAQ: http://www.faqs.org/faqs/C-faq/faq/ <blockquote> 1.7: What's the best way to declare and define global variables and functions? A: First, though there can be many "declarations" (and in many translation units) of a single "global" (strictly speaking, "external") variable or function, there must be exactly one "definition". (The definition is the declaration that actually allocates space, and provides an initialization value, if any.) The best arrangement is to place each definition in some relevant .c file, with an external declaration in a header (".h") file, which is #included wherever the declaration is needed. The .c file containing the definition should also #include the same header file, so that the compiler can check that the definition matches the declarations. </blockquote> Unfortunately, I seem to get a lot of errors like Error[115] C:\DAVID\GRAPHI~1\LCD_CO~1\TEST.ASM 4 : Duplicate label ("times1.5" or redefining symbol that cannot be redefined) Error[115] C:\DAVID\GRAPHI~1\LCD_CO~1\TEST.ASM 5 : Duplicate label ("ACC0" or redefining symbol that cannot be redefined) The odd thing is, MPASM claims there is a "duplicate", yet it only shows an error in one place. When I accidentally make ``real'' duplicates, MPASM usually shows me both places. Is this a bug in MPASM ? I seem to get some kind of error no matter how I tweak my ``test.inc'' file. If I replace ``EXTERN'' with ``GLOBAL'' in that file, I get Error[113] C:\DAVID\GRAPHI~1\LCD_CO~1\MAIN.ASM 38 : Symbol not previously defined (times1.5) Error[113] C:\DAVID\GRAPHI~1\LCD_CO~1\TEST.INC 17 : Symbol not previously defined (ACC0) . Here's my 3 test files: test.inc, test.asm, main.asm ; test.inc ; subroutines EXTERN times1.5 ; parameters for subroutines (registers) EXTERN ACC0 EXTERN ACC1 EXTERN TEMP0 EXTERN TEMP1 ; end file test.inc ; test.asm INCLUDE test.inc ; module definition file shared_math_stuff UDATA_shr ACC0 res 1 ACC1 res 1 TEMP0 res 1 TEMP1 res 1 test_subs CODE times1.5: ; ACC = ACC * 1.5 ; Temp = TEMP ; ACC size = 8 bits ; Error = 0.5 % ; Bytes order = little endian ; Round = yes ; ; ALGORITHM: ; Clear accumulator ; Add input * 2 to accumulator ; Add input * 1 to accumulator ; Shift accumulator right (LSb to carry) ; If carry set, increment accumulator ; Move accumulator to result ; Approximated constant: 1.5, Error: 0 % ; Input: ACC0, 8 bits ; Output: ACC0 .. ACC1, 9 bits ; Code size: 20 instructions ; ;copy accumulator to temporary movf ACC0, w movwf TEMP0 ;shift temporary left 1 times clrc rlf TEMP0, f clrf TEMP1 rlf TEMP1, f ;add temporary to accumulator clrf ACC1 movf TEMP0, w addwf ACC0, f movf TEMP1, w skpnc incfsz TEMP1, w addwf ACC1, f ;shift accumulator right once and ;increment if carry set rrf ACC1, f rrf ACC0, f skpc goto no_inc incf ACC0, f skpnz incf ACC1, f no_inc ; Generated by http://www.piclist.com/cgi-bin/constdivmul.exe (November 17, 2000 version) ; Thu Apr 05 17:18:58 2001 GMT END ; end file test.asm ; main.asm LIST P=PIC16F877 INCLUDE P16F877.INC ;INCLUDE REGISTER DEFINITION FILE INCLUDE test.inc ; module definition file ; ================ ; Reset vector STARTUP CODE 0x0000 RESET: NOP ;REQUIRED BY ICD PAGESEL beginning GOTO beginning ;INITIALIZE PROCESSOR AFTER RESET shared_stuff UDATA_shr ; Let linker allocate space for these. ISR_W res 1 ; must be in a ``global'' register or in every page at the same offset. idle_count res 4 endtime res 2 ; 16 bit return value from read_timer1(). TMPH res 1 TMPL res 1 beginning CODE beginning: BCF INTCON,7 ;GLOBALLY DISABLE INTERRUPTS BTFSC INTCON,7 ;BRANCH IF INTERRUPTS ARE DISABLED GOTO RESET ;ELSE, TRY TO DISABLE AGAIN MAINLP: ; [FIXME: do something useful here] CALL times1.5 GOTO MAINLP END ; end file main.asm -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email spam_OUTlistservTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

Assemblers are generally less flexible with things like symbols and scoping than the average high level language... Unfortunately, I seem to get a lot of errors like Error[115] C:\DAVID\GRAPHI~1\LCD_CO~1\TEST.ASM 4 : Duplicate label ("times1.5" or redefining symbol that cannot be redefined) This happens when your code contains the equivilent of: EXTERN times1.5 times1.5: ;code (note times1.5 symbol is defined here.) right? (sorry about the tabs, Olin :-) I suspect that having declared that the symbol is external, the assembler doesn't want to see it defined internally... Your next examble tries to address exactly that issue: GLOBAL times1.5 times1.5: ;code (note times1.5 symbol is defined here.) and you get the complaint: Error[113] C:\DAVID\GRAPHI~1\LCD_CO~1\MAIN.ASM 38 : Symbol not previously defined (times1.5) I conclude here that the assmebler doesn't want to make a symbol global until after that symbol has been defined, ie it wants: times1.5: GLOBAL times1.5 ; code Or something similar. (Note that this is all guesses.) If your included file contains only global/external definitions, you'd want it at the END of the code rather than at the beginning... It also looks like you'll have problems using the standard C practice of using the same include file for all your source modules... You might want to check what the defaults are for an assembler. An assembler I used to use would automatically treat unresolved symbols as external, but required a special declaration to get symbols to be accessable form outside the module ("Intern", IIRC. (as opposed to local?) Go figure.) random symbols defined in a module were local ("static" in C parlance) unless specifically marked otherwise. There were also special operators that set symbols to various scopes at the time they were defined, ie: label1:: ; globally accessable label label2: ; local (per source module) label. I'm not that familiar with the PIC assemblers, but there may be similar capabilities... BillW -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body

> I seem to get some kind of error no matter how I tweak my ``test.inc'' file. If > I replace ``EXTERN'' with ``GLOBAL'' in that file, I get > Error[113] C:\DAVID\GRAPHI~1\LCD_CO~1\MAIN.ASM 38 : Symbol not previously > defined (times1.5) > Error[113] C:\DAVID\GRAPHI~1\LCD_CO~1\TEST.INC 17 : Symbol not previously > defined (ACC0) Don't put EXTERN and GLOBAL in include files. For an example, see http://www.embedinc.com/pic and check out the HAL project. This is a multi-module project with a common include file. This page also contains template files for a whole project. ******************************************************************** Olin Lathrop, embedded systems consultant in Littleton Massachusetts (978) 742-9014, olinKILLspamembedinc.com, http://www.embedinc.com -- http://www.piclist.com hint: To leave the PICList .....piclist-unsubscribe-requestKILLspam.....mitvma.mit.edu

Dear PIC programmers, William Chops Westfield <@spam@billwKILLspamcisco.com> on 2001-04-05 08:41:21 PM made some comments that led me to do a little experimentation. Along with the explaination from Douglas Wood, I've learned how to break programs up into several files and get them to compile, link together, and run without error. (Well, without syntax errors anyway). Douglas Wood <KILLspamdbwoodKILLspamKC.RR.COM> on 2001-04-07 10:08:26 AM mentioned > You have #included TEST.INC proper in TEST.ASM, but you also #include it in MAIN.ASM. Yes. That is the ``C Way''. I'm used to the ``C Way'' of breaking up a program into several files, as explained in the C FAQ: http://www.faqs.org/faqs/C-faq/faq/ <blockquote> 1.7: What's the best way to declare and define global variables and functions? A: First, though there can be many "declarations" (and in many translation units) of a single "global" (strictly speaking, "external") variable or function, there must be exactly one "definition". (The definition is the declaration that actually allocates space, and provides an initialization value, if any.) The best arrangement is to place each definition in some relevant .c file, with an external declaration in a header (".h") file, which is #included wherever the declaration is needed. The .c file containing the definition should also #include the same header file, so that the compiler can check that the definition matches the declarations. </blockquote> >I think you misunderstand the purpose for using an #include file. I think not. :-) I have some subroutines in one file (test.asm) that I want to call from another file (main.asm). The assembler needs to know that, both when it is compiling test.asm, and also when it is calling main.asm.The header file lists those subroutines. That is the purpose of the header file. At least, that is how things are done in C. What's the right way to do it in assembly ? >Put "GLOBAL TIMES1.5" in TEST.ASM and "EXTERN TIMES1.5" in MAIN.ASM. >Remember GLOBAL exports the label to other modules and EXTERN says that the >label is external to the current module. Ah. This works for me. Thanks. I didn't know that before. Olin Lathrop <RemoveMEolin_piclistTakeThisOuTEMBEDINC.COM> on 2001-04-06 06:29:56 AM suggested: > Don't put EXTERN and GLOBAL in include files. For an example, see > http://www.embedinc.com/pic and check out the HAL project. This is a > multi-module project with a common include file. This page also contains > template files for a whole project. Many people use a single common include file, and that works for them. I've been trained differently. I put related subroutines together in one file (of type ``.c'' or ``.asm''). Then I make a corresponding header file with the same name (of type ``.h'' or ``.inc'') that lists those subroutines, plus some English text on how to call the subroutines and what they do. This makes it easier for me to re-use that group of subroutines in a completely different project. I don't make *any* changes to that ``.asm'' file, nor to its associated ``.inc'' file; I just add the ``include __.inc'' line to my new ``main.asm'' file, and start calling those subroutines from within that ``main.asm'' file. -- David Cary -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics