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  1. Embedded Software & Tools
  2. EXT_EP-10804

Using --printf_support=minimal uses up much more stack than required

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      The internal RTS header file format.h has these lines ...

      #ifndef __FORMAT_H
#define __FORMAT_H
#include <stdarg.h>

#if defined (MINIMAL)
#define FORMAT_CONVERSION_BUFSIZE 32
#elif defined (__MSP430__)
#define F_CONVERSION_BUFSIZE      100
#define FLOAT_VALUE_BUFSIZE       32
#else
/****************************************************************************/
/*   The minimum max conversion size to be C89 compliant is 509             */
/****************************************************************************/
#define F_CONVERSION_BUFSIZE      510
#define FLOAT_VALUE_BUFSIZE       100
#endif

      The RTS source file _printfi.c has these lines ...

      /**************************************************************************/
/*  Full printf definition                                                */
/**************************************************************************/
#define _PRINTFI __TI_printfi
#include "_printfi_template.c"
#undef _PRINTFI
/**************************************************************************/
/*  No float printf definition                                            */
/**************************************************************************/
#define _PRINTFI __TI_printfi_nofloat
#define NOFLOAT
#include "_printfi_template.c"
#undef NOFLOAT
#undef _PRINTFI
/**************************************************************************/
/*  Minimal printf definition                                             */
/**************************************************************************/
#define _PRINTFI __TI_printfi_minimal
#define MINIMAL
#include "_printfi_template.c"
#undef MINIMAL
#undef _PRINTFI

      Note how _printfi_template.c is included three times. The file _printfi_template.c includes format.h. Because of the inclusion guards, this definition ...

      #if defined (MINIMAL)
#define FORMAT_CONVERSION_BUFSIZE 32

      ... is never seen. Even for --printf_support=minimal, FORMAT_CONVERSION_BUFSIZE is 510. Therefore this local buffer in the function _printfi_minimal ...

               char fld[FORMAT_CONVERSION_BUFSIZE];

      ... is 510 bytes, and not 32. This means _printfi_minimal uses much more stack space than required.

            syncuser TI User
            syncuser TI User
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              Created:
              Updated: