How to define stucture in asm?

Robert W said:

It cannot get through at all.

I'm not sure what you mean.  Please precisely describe what you expect to get, and what you actually get.

Thanks and regards,

-George 

Your example works fine for me and the latest TI C6000 compiler tools.  The input file I used is attached.  Compare it against your file?

5050.test.asm

%> cat test.asm
COORDT .struct            ; structure tag definition
X              .byte      ;
Y              .byte
T_LEN     .endstruct
COORD   .tag COORDT       ; declare COORD (coordinate)
        .bss COORD, T_LEN ; actual memory allocation

        LDB *+B14(COORD.Y), A2 ; move member Y of structure
                               ;;  COORD into register A2

%> cl6x -al test.asm

%> cat test.lst
TMS320C6x Assembler Unix v7.4.1 Tue Sep  4 16:55:27 2012

Tools Copyright (c) 1996-2012 Texas Instruments Incorporated
test.asm                                                             PAGE    1

       1                    COORDT .struct            ; structure tag definition
       2          00000000  X              .byte      ;
       3          00000001  Y              .byte
       4          00000002  T_LEN     .endstruct
       5                    COORD   .tag COORDT       ; declare COORD (coordinate)
       6 00000000                   .bss COORD, T_LEN ; actual memory allocation
       7
       8 00000000 0100012C-         LDB *+B14(COORD.Y), A2 ; move member Y of structure
       9                                                   ;;  COORD into register A2

No Assembly Errors, No Assembly Warnings

%> dis6x test.obj
Disassembly of test.obj:

TEXT Section .text (Little Endian), 0x20 bytes at 0x0
00000000             .text:
00000000   0100012c           LDB.D2T1      *+B14[1],A2
00000004   00000000           NOP
00000008   00000000           NOP
0000000c   00000000           NOP
00000010   00000000           NOP
00000014   00000000           NOP
00000018   00000000           NOP
0000001c   00000000           NOP

Hi,

With CCS v5 IDE, your test.asm building process cannot build because there is no main. My previous question is that I cannot find any way to build a project with that stucture definition.

I have found a thread on the forum.

http://e2e.ti.com/support/development_tools/compiler/f/343/t/192527.aspx

It says the red part is not supported by the compiler. That is the cause I cannot build the stucture. I still don't know whether you can build a structure with the red part (The compiler calculates the offset).

Thanks.

MY_STRUCT_type .struct

fee            .word

fi             .word

foe            .word

fum            .word

MY_STRUCT_LEN  .endstruct

MY_STRUCT      .tag MY_STRUCT_type

;              .bss MY_STRUCT, MY_STRUCT_LEN

               .bss MY_STRUCT, 16

More clearly, can you use .tag directive for a stucture?

It says the red part is not supported by the compiler. That is the cause I cannot build the stucture. I still don't know whether you can build a structure with the red part (The compiler calculates the offset)

With CGT 7.3.3 it works. Mybe you could post the erros reported by the assmbler.

You can also try the $sizeof() operator:

COORDT .struct
X .byte
Y .byte
  .endstruct

COORD    .tag COORDT
    .bss COORD, $sizeof(COORDT)

Note that if the struct is shared between C and asm, you should consider using the .cdecls directive and define the struct in a C header file (then looking at the asm listing you can view how the C structure are converted).

Hi,

Try the attached project

If incompatible with your CCS (it is generated with CCS 5.1, CGT 7.3.3), you can extract the source file hello.c, coord.h, coord.asm and insert them in a new project.

Inside coord.asm you can choose to use the C struct declaration or the assmbler one (just change  "use_c_declaration    .set 0" to "use_c_declaration    .set 1" to use the C header file).

4846.c66_asm_struct_example.zip