readme.1st

Montavista Linux 下的多平台编译软件xdc

     installation -- /c6xtools/solaris/bin then set LO_PATH to be
 
     setenv LO_PATH /c6xtools/solaris

-------------------------------------------------------------------------------
2.04.  Tips on printing from linear assembly
-------------------------------------------------------------------------------
The following code can be used for printing information within linear
assembly.  This can be useful for printf style debugging of linear
assembly code.


=============================
<print.inc>
=============================
         .global _print_int
         .global _print_nl   
         .global _print_line 
         .global _print_lint 

PRINT_INT  .macro  tag,value

          MVKL  tag,  print_int_private
          MVKH  tag,  print_int_private

          .call _print_int(print_int_private,value);
          .endm

PRINT_NL   .macro

           .call _print_nl()
           .endm

PRINT_LINE  .macro

           .call _print_star()
           .endm

=============================
<print.c>
=============================
#include <stdio.h>
#include <stdlib.h>

void print_int(char *s,int word)
{
  printf("%s:,%.8x: \t",s,word);
}

void print_nl()
{
  putchar('\n');
}

void print_line()
{
  printf("-----------------------------------------------------------------\n");
}

=============================
<foo.sa>
=============================
           .data
A_astring   .string "A_a",   0
B_bstring   .string "B_b",   0
A_sum       .string "A_sum", 0

            .text
            .include "print.inc"
            .global _foo
_foo:       .cproc   A_a, B_b

            .reg     print_int_private
            .reg     A_c

            ADD        A_a,         B_b,       A_c

            PRINT_INT  A_astring,   A_a
            PRINT_INT  B_bstring,   B_b
            PRINT_NL
            PRINT_INT  A_sum,       A_c
            .return


-------------------------------------------------------------------------------
2.05. Old code that uses dynamic casts is incompatible with newer RTS libs
-------------------------------------------------------------------------------
The names of run-time support functions used to implement C++ dynamic casts
changed in the run-time support libraries of the 5.1.x version of the code 
generation tools.  Therefore, object and library code that use dynamic casts
compiled with code generation tools 5.0.x and prior will not link properly 
with run-time support libraries from code generation tools version 5.1.x and 
later.  Please re-compile the source code with a 5.1.x or later version of the 
code generation tools.


*******************************************************************************
3. Known Issues      
*******************************************************************************

------------------------------------------------------------------------------
SDSsq11516
------------------------------------------------------------------------------
Summary  : Long types for bitfields are not supported although they're legal in
           C++

Long bitfield types are not supportd in C++ programs on the C6x.

------------------------------------------------------------------------------
SDSsq11669
------------------------------------------------------------------------------
Summary  : C++ allows enumerators larger than 'int' but C6x Compiler does not

C++ allows enumerators larger than an int.  Currently, the C6x
compiler forces all enumerators to ints.

------------------------------------------------------------------------------
SDSsq11721
------------------------------------------------------------------------------
Summary  : "Extern inline" functions are not supported in C6x C/C++ Compiler

"Extern inline" functions are not supported by the C6x C/C++ compiler.
The V3.00 compiler/code generator does not create globally accessible
code for functions which are declared inline. A simple example is:

inline int x() { return 1; }
int y() {return 2;}

When compiled with cl6x -k -c test.c a warning is produced:
"test.c", line 1: warning: function "x" was declared but never
referenced

and the resulting assembler file (test.asm) does not contain any code
for x(). 

See section "Workaround" for a workaround to this problem.



Workaround:
-----------

As a workaround that involves the least amount of code modification, define 
a macro to be "static inline" and use that macro as the inline modifier
for these functions.  In the normal case, these functions will be inlined.
To generate callable versions of these functions, also compile the header
files containing the inlined functions with this new macro undefined. 

For example: 

---------------------------------------------------------------------- 
header.h: 

#ifdef NO_INLINE 
#define STATIC_INLINE 
#else 
#define STATIC_INLINE static inline 
#endif 

/* Replace the inline modifier with STATIC_INLINE for all inlined */
/* functions which you also want to generate a callable version.  */ 
STATIC_INLINE int x() { return 1; } 

---------------------------------------------------------------------- 
foo.c: 

/* Inline occurs normally in this file */ 
#include "header.h" 

int y() { return x(); } 

---------------------------------------------------------------------- 
body.c: 

/* Compile this file to generate callable versions of all inline */
/* functions which use the STATIC_INLINE macro.                  */ 
#define NO_INLINE 
#include "header.h" 


------------------------------------------------------------------------------
SDSsq19038
------------------------------------------------------------------------------
Summary  : Global variables are not visible in watch window if using the -h
           option

If the user selects the option "Make Global Symbols Static (-h)" under 
the Linker tab in tbe Build Options window, they will not be able to 
monitor global variables in the watch window while running that program.

If the user attempts to watch a global variable, the watch window will 
display "Identifier not found."

This problem did not exist in CCS 1.20.

Workaround:
-----------

Resolve conflicting global variable names so -h is not required.

------------------------------------------------------------------------------
SDSsq23983
------------------------------------------------------------------------------
Summary  : STRUCT_ALIGN pragma does not work for array of struct

The compiler does not correctly align an array of STRUCT_ALIGNed    
structures.  It does, however, place the structures the correct    
distance apart.

------------------------------------------------------------------------------
SDSsq30228
------------------------------------------------------------------------------
Summary  : Linker unexpectedly adds STYP_DATA flag into a text section 

A zero-length input section's header flags may affect the section
header flags of the output section it is contained in.

------------------------------------------------------------------------------
SDSsq32304
------------------------------------------------------------------------------
Summary  : -o timeout option for load6x doesn't work if there are no CIO
           functions.

The timeout  feature(-o xxx option) in load6x (TMS320C6x Standalone 
Simulator Version 4.20 and also 4.3)doesn't work if there are no CIO 
functions. In the document spru187k "TMS320C6000 Optimizing Compiler 
User's Guide" ,the description for the options that control the stand-
alone simulator says that -o xxx option will set overall timeout to xxx 
minutes. The stand-alone simulator aborts if the loaded program is not 
finished after xxx minutes.

Workaround:
-----------

If the source file contains CIO functions such as printf then the 
simulator will abort the program after specified minutes and works fine.

------------------------------------------------------------------------------
SDSsq32879
------------------------------------------------------------------------------
Summary  : STABS variables declared in loop bodies are promoted to function
           scope

When building the following program with STABS debug, you will notice 
that the variable "j", which is declared in the for loop, appears in 
_main's function scope (not the loop scope) when you look at the symbol 
table:

#include <stdio.h>

int main()
{
   int i;

   for (i = 0; i < 10; i++)
   {
      int j;

      j = i * 2;
      printf("%d\n", j);
   }
   return 0;
}

Workaround:
-----------

Use DWARF debug.

------------------------------------------------------------------------------
SDSsq32976
------------------------------------------------------------------------------
Summary  : Relocation value is wrongly calculated by assembler

Assembler incorrectly calculates wrong relocation value 'go - gap' 
example below --

  .sect mysect
  .global _main
_main:
gap .equ 0x90000000
    .word 0x1234
    .word 0x1234	
go  mvkl (go - gap), a3
    mvkh (go - gap), a3

And link this object section to address 0x90000000.


Workaround:
-----------

For the particular situation cited in the test case, the
user can define a symbol at link-time associated with the beginning
of the section containing the symbol "go" and then refer to
that symbol when computing the section-relative offset of the
symbol.

For example, remove the definition of 'gap' from the assembler file
and add a .global directive that allows you to reference a linker
defined version of 'gap' (described in the linker command file below):

    .global  gap    ; add this directive
    .sect mysect   
    .word 0x1234
    .word 0x1234
go  mvkl (go - gap), a3
    mvkh (go - gap), a3

Now, in the linker command file, the user will define a symbol
that is associated with the start of the section.  This is done
with the operator 'start' in the example below:

   SECTIONS
   {
     mysect: load = 0x90000000, start(gap) {*(mysect)}
   }