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C251 User's Guide

C251 Introduction Compiling Programs Language Extensions Preprocessor Advanced Programming Error Messages Library Reference Library Files Source Code Standard Types jmp_buf va_list Macros CBYTE CVAR CARRAY DARRAY DBYTE DVAR HARRAY HBYTE HVAR NARRAY NBYTE NVAR XARRAY XBYTE XVAR Routines by Category Buffer Manipulation Routines Character Routines Data Conversion Routines Intrinsic Routines Math Routines Memory Allocation Routines Stream I/O Routines String Routines Variable Length Argument Routines Miscellaneous Routines Include Files SFR Definitions absacc.h assert.h ctype.h float.h intrins.h limits.h math.h setjmp.h stdarg.h stddef.h stdio.h stdlib.h string.h Reference _chkdouble_ _chkfloat_ _crol_ _cror_ _getkey _irol_ _iror_ _lrol_ _lror_ _nop_ _testbit_ _tolower _toupper abs acos asin assert atan atan2 atof atoi atol cabs calloc ceil cos cosh exp fabs fcalloc ffree finit_mempool floor fmalloc fmemcpy fmemset frealloc free getchar gets hmemccpy hmemchr hmemcmp hmemcpy hmemmove hmemset hstrcmp hstrcpy hstrlen hstrncpy init_mempool isalnum isalpha iscntrl isdigit isgraph islower isprint ispunct isspace isupper isxdigit labs log log10 longjmp malloc memccpy memchr memcmp memcpy memmove memset modf offsetof pow printf putchar puts rand realloc scanf setjmp sin sinh sprintf sqrt srand sscanf strcat strchr strcmp strcpy strcspn strlen strncat strncmp strncpy strpbrk strpos strrchr strrpbrk strrpos strspn tan tanh toascii toint tolower toupper ungetchar va_arg va_end va_start vprintf vsprintf xcalloc xfree xinit_mempool xmalloc xmemcpy xmemset xrealloc Appendix

Library Reference

The C251 run-time library provides more than 100 predefined functions and macros you may use in your 251 C programs. The library makes embedded software development easier by providing routines that perform common programming tasks such as string and buffer manipulation, data conversion, and floating-point math operations.

The routines in this library conform to the ANSI C Standard. However, some functions differ slightly in order to take advantage of the features of the 251 architecture. For example, the isdigit function returns a bit value as opposed to an int. Where possible, function return types and argument types are adjusted to use the smallest data type possible. In addition, unsigned data types are favored over signed types.

The floating pointer error handling is performed via the functions _chkfloat_ and _chkdouble_ rather then using a global variable errno for the error status. This method fits the needs of embedded systems, where the error status is checked separately in the main and interrupt function or in each RTX251 task.

These changes to the standard library provide a maximum of performance while reducing program size.

All routines in this library are implemented to be independent of and to function using any register bank.

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