Calling C function from asm prog

Which compiler are you using?

NC100 compiler with HEW IDE

According to the user manual (rej10j2009):

Assuming that your C-function is named "pff", you would prepend either the $ or _ character depending on whether the function has arguments passed to it.

I would guess that the problem is the ".c" that is being flagged as an error.  Why is this included?

You are right the original error was due to the ".c" but when I removed it the error is now: Undefined symbol exist '_pff' despite the file is clearly included in the project under C source file directory.

Is there any working example program I can look at in order to compare with mine

Thks for your help

Is this a compiler error or a linker error for the undefined symbol?

Here is the complete error message from assembly compiler phase:

C:\0DATA\32C\32C Projects\R32C_GFORCE_GRAPHIC\R32C_GFORCE_3\main.a30
R32C/100 Series Assembler system V.1.02.01
Copyright (C) 2006 (2007 - 2010) Renesas Electronics Corporation.
and Renesas Solutions Corporation. All rights reserved.
macro processing now
assembler processing now
----*----*----*----*----*----*----*----*----*----*-
C:\0DATA\32C\32C Projects\R32C_GFORCE_GRAPHIC\R32C_GFORCE_3\main.a30(461) : Error (asp100): Characters exist in expression
---
TOTAL ERROR(S) 00001
TOTAL WARNING(S) 00000
TOTAL LINE(S) 05415 LINES
CODE 00000625(000271H) program
( C:\0DATA\32C\32C Projects\R32C_GFORCE_GRAPHIC\R32C_GFORCE_3\main.a30 )

The error shown is, "Characters exist in expression" which is quite different than "Undefined symbol..."

The error shown is, "Characters exist in expression" which is quite different than "Undefined symbol..."

Sorry for late reply, I was ut for a while !

Sorry for late reply, I was out for a while ! 

When the command is: jsr $pff.c

the error is: Error (asp100): Characters exist in expression

When the command is: jsr $pff

the error is: Error (asp100): Undefined symbol exist '$pff'

Errors are the same if I used '_' instead of '$'

Here is the list of C files included in the project

That would be great if I could find a sample program calling a C function from an assembly program !

Can you generate the assembly code for the "pff.c" (or the assembler listing)?

This is an assembler error because you have an undefined name. I have used the NC30 compiler a lot for R8C devices. And there you also needed to define the c function name. Assuming your c function is pff() then you need todo the following:

.glb    _pff

jsr     _pff

The assembler will then recognise the name. And the linker should than link it to the c file.

That makes sense - some assemblers require symbol references, some don't, and some have options to ignore undefined symbols.  One could also potentially get the C-compiler to generate such a reference by doing something like this:

extern int pff; int GetPFF(void) { return pff; }

Thanks NGE, you were right !

I did have a '.glb' declaration but I forgot the underscore character (shame on me...)

Now the compilation process is completed without any error (see below)

assembler processing now

C:\0DATA\32C\32C Projects\R32C_GFORCE_GRAPHIC\R32C_GFORCE_3\main.a30
R32C/100 Series Assembler system V.1.02.01
Copyright (C) 2006 (2007 - 2010) Renesas Electronics Corporation.
and Renesas Solutions Corporation. All rights reserved.
macro processing now
assembler processing now
----*----*----*----*----*----*----*----*----*----*----
TOTAL ERROR(S) 00000
TOTAL WARNING(S) 00000
TOTAL LINE(S) 05416 LINES
CODE 00000629(000275H) program
( C:\0DATA\32C\32C Projects\R32C_GFORCE_GRAPHIC\R32C_GFORCE_3\main.a30 )
----*----*--
Phase R32C/100 Assembler finished

But now linkage pass 2 is faulty, see result below:

Phase R32C/100 Linker starting

Linkage Editor (ln100) for R32C/100 Series V.1.02.00.001

Copyright (C) 2006 (2007 - 2010) Renesas Electronics Corporation.

and Renesas Solutions Corporation. All rights reserved.

SentinelRMS (C) 1989-2006 SafeNet, Inc. All rights reserved.

now processing pass 2

Projects\R32C_GFORCE_GRAPHIC\R32C_GFORCE_3\Debug\main.r30"

C:\0DATA\32C\32C Projects\R32C_GFORCE_GRAPHIC\R32C_GFORCE_3\main.a30(461) : '_pff' value is undefined

Any clue ?

I dived in an old project with a R32C/111 where in the C file I have the following:

void initSystem(void);

void initSystem(void){

}

The declaration of the function can also done in an include. Maybe this declaration is needed for the linker.

And in the assembly:

.glb		_initSystem
jsr.a		_initSystem

It's now working fine !

I used the following:

jsr _pff to call a simple C function and

jsr $open when parameters have to be transmitted

Many thanks NGE for your kind help !!

Following successfully calling C functions from asm, I am now facing a new issue:

My data are defined as follows in asm project

;********************************************************
; RAM area allocation
;********************************************************

.section data_SB8, data

record_size: .blkl 1

but I don't know how to include variable and structure defined in C language functions to my data section

defined in asm

Here is an example of a structure defined in H file

/* Directory object structure */

typedef struct {
WORD index; /* Current read/write index number */
BYTE* fn; /* Pointer to the SFN (in/out) {file[8],ext[3],status[1]} */
CLUST sclust; /* Table start cluster (0:Static table) */
CLUST clust; /* Current cluster */
DWORD sect; /* Current sector */
} DIR;

and variable defined in C file like:

BYTE i, c;

Thks for your help

There is no good way to define a c structure in asm. You can manually define offsets in asm for the variables in the c structure. But when you change the structure you need to redefine your asm offsets.

A better way to use c structures in asm is to make use of the asm function also known as inline assembly. With this you can imbed asm in a c function. A small example from the NC100 compiler manual (chapter B2):

void func(void) 
{ 
    short idata; 
    short a[3]; 
    struct TAG{ 
        short i; 
        short k; 
    } s; 
    : 
    asm(" MOV.W R0, $$[FB]", idata); 
    : 
    asm(" MOV.W R0, $$[FB]", a[2]); 
    : 
    asm(" MOV.W R0, $$[FB]", s.i); 
    (Remainder omitted) 
    : 
    asm(" MOV.W $$[FB], $$[FB]", s.i, a[2]); 
}

And:

short idata; 
short a[3]; 
struct TAG{ 
    short i; 
    short k; 
} s; 
void func(void) 
{ 
    : 
    asm(" MOV.W R0, $$", idata); 
    : 
    asm(" MOV.W R0, $$", a[2]); 
    : 
    asm(" MOV.W R0, $$", s.i); 
    (remainder omitted) 
    : 
}