CROSSWARE C8051NT ANSI C Compiler for Windows

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CROSSWARE C8051NT 7 The Crossware C8051NT is a sophisticated ANSI standard C compiler that generates code for the 8051 family of microcontrollers.

1 CROSSWARE C8051NT 7 The Crossware C8051NT is a sophisticated ANSI standard C compiler that generates code for the 8051 family of microcontrollers. It provides numerous extensions that allow access to 8051 specific features so that you can write your code completely in the C language without the need to resort to assembler code. It supports large, small and tiny memory models so you can create code for all 8051 variants whether or not they have external ram. It provides advanced features such as smart pointers and cross-module type checking to ease and speed the development process. It comes complete with the Crossware Embedded Development Studio and runs under Windows 9x, Windows NT 4.0, Windows 2000 and Windows XP ANSI C Compiler for Windows The ANSI C compiler protects your investment by ensuring future portability of your C source specific extensions enable you to access all of the resources of the 8051 and its variants from C. Smart pointers which can work out for themselves which memory area they are pointing to. This enables you to avoid inefficient 3 byte pointers yet still write ANSI C compatible code. Generates fast in-line code with a minimum of library calls for high speed performance on your target board. Optional common code merging for when code size is an issue. Full type checking across modules traps programming errors and ensures that your C variables, function arguments, structure members, etc are consistent across your source files and with the appropriate libraries. Comprehensive source level debug output. Pre-written library routines, including high speed 32 bit and 64 bit floating point arithmetic. Register bank independent code. Easy to use C interrupt support with optional register bank switching. Memory bank switching to break the 64k barrier. Tiny, small and large memory models. Place variables in any memory area. Supports all 8051 variants. Wide range of output formats. Integrated relocatable assembler. Highly user friendly Embedded Development Studio integrated development environment (see separate data sheet). Data output for Embedded Development Studio source code browser 1 Crossware Products Old Post House Silver Street Litlington Royston Herts SG8 0QE United Kingdom Telephone + 44 (0) Facsimilie + 44 (0) Web sales@crossware.com REF: C8051NT/0302

2 OVERVIEW OVERVIEW The package includes the following tools and utilities: optimizing ANSI C compiler C support libraries relocatable macro cross assembler relocating linker make utility library manager Embedded Development Studio which includes integrated project creation and maintenance utility integrated editor integrated terminal emulator on-line help All of these tools and utilities are Win32 applications built to make the most of your 32 bit computing environment. All tools can be used outside of the Embedded Development Studio if reuired using conventional commandline instructions. COMPILER OPTIMIZING C COMPILER Language Definition The compiler conforms to the ANSI C specification and in addition provides a number of general enhancements including: variables can be any length with all characters significant the C++ commenting convention "//" is supported the_interrupt keyword declares a C function as an interrupt routine the _persist keyword declares that a variable will retain its contents (eg. in battery backed up ram) during power down and should therefore not be initialized. The support libraries are a subset of the ANSI standard libraries. The supported functions are listed below specific language extensions are described below. 2

3 Data sizes The compiler uses the following sizes for the various C data types: char and unsigned char short int and unsigned short int int and unsigned int long and unsigned long float double long double enum bit fields bit pointers to variables pointers to functions : 1 byte : 2 byte : 2 bytes : 4 bytes : 4 bytes (32 bits) : 8 bytes (64 bits) : 8 bytes (64 bits) : up to 4 bytes (minimum size to accommodate members) : up to 32 bits : 1 bit : 1,2 or 3 bytes : 2,3 or 4 bytes Optimizations Optimizations include: constant folding dead code elimination strength reduction algebraic simplification jump/branch optimization suppression of integral promotion global register allocation common code merging removal of unreferenced local data 8051 Language Extensions In addition to the general extensions described above, the compiler supports numerous 8051 specific extensions which enable you to maximise your use of the internal resources of the 8051 and its variants. These include: Direct access to the bits of variables located in the bdata memory area. Direct access to 8 bit sfr's, 16 bit sfr's and sfr bits to which you can allocate any C variable name. Additional interrupt ualifiers to allow you to specify the interrupt vector that a function will use (the compiler optionally generates all vectoring code) and an optional register bank for register bank switching. Qualifiers to enable you to place variables in bit, data, idata, bdata and xdata memory areas irrespective of the memory model being used (variables declared as const are automatically located in code space). 3

4 Smart Pointers The compiler supports pointers that point to any specific memory area and generic 3 byte pointers that can point to all memory areas. Some 8051 C compilers default to generic 3 byte pointers unless you declare a memory specific pointer using a ualifying keyword. It is then necessary to decorate your source code with non-ansi keywords in order to avoid program inefficiency. This decoration may be memory model specific and so if you switch memory models you have to change your source code too. The Crossware 8051 ANSI C compiler avoids this problem. Although it supports these pointer ualifiers, in most cases it is not necessary to use them. Instead any pointer that is not ualified is a smart pointer. It will then work out for itself from the way it is used what type of pointer it should be. This leaves you free to write ANSI compatible, memory model independent source code without any unnecessary loss of efficiency. Without Smart Pointers: int func (char _xdata * pch1) { char _xdata * pch2 ; pch2 = pch1 } int func ( char _idata * pch1) { char _idata * pch2 ; pch2 = pch1 ; } With Smart Pointers: Large memory model Small memory model int func ( char * pch1) { char * pch2 ; pch2 = pch1 ; } Any memory model How to avoid 3 byte generic pointers Floating Point The Crossware 8051 ANSI C compiler supports both 32 bit and 64 bit floating point objects. 32 bit floating point objects contain only 23 bits of precision (the rest is used by the exponent and sign) and are therefore less precise than 32 bit long integers. They are however ideal for the application where low precision floating point arithmetic is all that is reuired. 64 bit floating point objects contain 53 bits of precision and are therefore ideal where arithmetic accuracy is an important issue. All floating point arithmetic and normalisation routines are hand-coded in 8051 assembler to provide fast and compact library code. 4

5 Memory Models Large Memory Model The large memory model is used for target systems that have external data memory (xdata). Local variables and function arguments are located in xdata memory and, by default, global and static variables are located here too unless they are const objects (which are located in program memory). If the target system has no xdata memory, the large memory cannot be used. Small Memory Model The small memory model is used for target systems that do not have external data memory or where the data reuirements of the program allow small memory model to be used. Local variables and function arguments are located in internal data memory (idata) and, by default, global and static variables are located here too unless they are const objects (which are located in program memory). Global and static variables can be located in external data memory (if available) by ualifying them with the _xdata keyword. Tiny Memory Model The tiny memory model is used for programs that are limited to 2K bytes in size and that do not use external data memory at all. The compiler generates ACALL and AJMP instructions as opposed to LCALL and LJMP. No references to external data memory are allowed and so the compiler will never generate the MOVX instruction. The tiny memory model is essential for 8051 variants that do not support the LCALL, LJMP and MOVX instructions such as the Philips 8XC750, 8XC748, 8XC751, 8XC749 and 8XC752. Debug Output The compiler can generate debug records in three formats - IEEE695 and OMF51 and extended OMF51. IEEE695 records are very detailed and contain comprehensive information about the program source code, C variables, structures, unions, memory banks etc. The Crossware 8051 Virtual Workshop takes full advantage of this format. OMF51 and Extended OMF51 contain less detailed debugging information but are more widely recognised by third party debugging tools. 5

6 Reentrant/Non-reentrant Functions The compiler will produce both reentrant and non-reentrant functions. Reentrant functions are fully compatible with ANSI C and allow recursive calls within and between functions. Space for parameters and local variables is allocated dynamically on a stack located in either internal indirectly addressable data memory or external data memory depending on the memory model. However, the 8051 instruction set is not particularly well suited to conventional stack operations (it has no indexed addressing modes for accessing data memory) and a dramatic improvement in program size and speed can be achieved by implementing a statically allocated stack system. With this approach, each function has it's own fixed data memory for storage of its parameters and local variables. Because this memory is in a fixed location, if the function is called again while it is already running, the parameters and local variables of the second call will overwrite those of the first call. The function cannot be reentered and it is therefore a non-reentrant function. To minimise memory usage the linker carries out an analysis of the complete program and constructs a function call tree. It uses this call tree to determine which functions can safely share stack space. The stack space for functions that cannot possibly invoke each other are then overlaid. The linker is also able to exactly determine the total stack space reuired by functions that have a variable number of arguments (such as printf() and scanf()) and so no space is wasted allowing for additional arguments that are never present. (Some 8051 C compilers reuire the amount of reserved space to be specified by the programmer). A compiler command line option, on a dialog box option in the Embedded Development Studio, switches between the default between reentrant and non-reentrant functions. In addition the _reentrant and _nonreentrant keywords can be used to override the default for particular functions. 6

7 I/O with or without streams Standard C uses streams for input to and output from the running program. Five streams will automatically be created at program startup and these are designated stdin, stdout, stderr, stdprn, and stdaux. Streams can be redirected, duplicated and can provide the basis of a filing system allowing new streams to be created, opened and closed. Functions such as fprintf(), sprintf(), fputs(), fgets() etc are stream based functions. Streams are essential if existing C code is being pointed to the The Crossware compiler supports streams. However, streams also consume memory (each stream reuires a structure) and, due to the need for common behaviour between different stream types, they can be relatively inefficient. Therefore the Crossware compiler also provides an alternative to streams. Streamless versions of for example puts(), gets(), printf(), scanf() etc are provided. A compiler option allows streams to be enabled or disabled. The streamed or streamless versions of the appropriate functions will automatically be included depending upon the option used. In-Line Assembler The compiler provides numerous features that allow you to access the 8051 features at the C source level. Nevertheless you can still embed assembler in your C code if you wish using the #asm/#endasm directives. The #asm/#endasm directives allow assembler code to be placed anywhere in a C source file, not just within functions. In addition the compiler supports the _asm keyword. This has a number of advantages over the #asm/#endasm approach. Firstly _asm statements can be generated using C macros and with full macro token replacement. Secondly, the C compiler can replace C variable names with the appropriate sub-string allowing easy access to global, static and local variables and parameters. #define ResetWatchdog() \ _asm ( mov 0c7h,#0aah ); \ _asm ( mov 0c7h,#055h ); \ _asm ( setb 0d8h ); main() { while (1) { ResetWatchdog(); HandleInput(); ResetWatchdog(); PerformAction(); } } 7

Code Bank Switching The compiler supports code bank switching. This allows programs greater than 64K bytes to be produced. Code bank switching is easy to use.

8 Code Bank Switching The compiler supports code bank switching. This allows programs greater than 64K bytes to be produced. Code bank switching is easy to use. You include a pragma in your source code ahead of the functions that you want to include in a switchable bank and you tell the linker where the code banks are located. The compiler and linker take care of everything else. You can run the complete program in the 8051 Virtual Workshop using an extension configured to support your code bank switching protocol. Source Code Browsing The compiler optionally generates information on all of the definitions of and references to the identifiers used in your program. This includes functions, function parameters, local variables, global and static variables, enum identifiers, typedefs, goto labels and the tag names of structures, unions and enums. The Embedded Development Studio will then use this information to allow you to uickly navigate through your source code. Interrupt Functions Creating interrupt functions is simply a matter of ualifying it with the _interrupt keyword and specifying a vector number. The compiler takes care of everything else - creating the absolute code at the vector address to jump to the function when the interrupt occurs and saving and restoring the appropriate registers and other internal locations that are reuired during the interrupt. The compiler calculates the vector address from the vector number and so interrupt functions for all 8051 variants can be automatically created. You can also specify a register bank and the compiler will generate the reuired code to switch register banks on entry to the interrupt function. The compiler generates register bank independent code and so register banks can be switched without any adverse effects. 8

9 Variant Specific Features Siemens Arithmetic Unit The Siemens 80C517 family of chips provide an arithmetic unit which performs multiplication, division, shifting and normalisation routines. The compiler optionally takes advantage of this unit for unsigned 16 bit arithmetic. C Library Support Routines abs() acos() acosl() asin() asinl() atan() atanl() atan2() atan2l() atof() atofl() atoi() atol() clearerr() ceil() ceill() cos() cosl() cosh() coshl() exit() exp() expl() fabs() fabsl() _fcvt() ferror() fgetc() fgets() fileno() floor() floorl() fprintf() fputc() fputs() free() frexp() frexpl() fscanf() getc() getchar() getche() gets() isalnum() isalpha() isacii() iscntrl() isdigit() isgraph() islower() isprintf() ispunct() isspace() isupper() isxdigit() itoa() labs() ldexp() ldexpl() log() logl() log10() log10l() longjmp() ltoa() malloc() memchr() memcmp() memcpy() memmove() memset() pow() powl() printf() putc() putchar() puts() rand() sbrk() scanf() setjmp() sin() sinl() sinh() sinhl() sprintf() srt() srtl() srand() sscanf() strcat() scanf() strchr() strcmp() strcpy() strcspn() strlen() strncat() strncmp() strncpy() strpbrk() strrchr() strspn() strstr() tan() tanl() tanh() tanhl() time() toascii() tolower() toupper() ultoa() ungetc() ungetch() 9

10 LINKER RELOCATING LINKER The linker combines object modules created with the compiler and/or the assembler to create the final code that will run on your target system. It carries out the following functions: scans each module to collect segment and variable information arranges and positions segments at appropriate memory locations to suit the memory organisation of the target system and any specific location information supplied by the user finalises the values of all variables and calculates the results of any incomplete expressions extracts and relocates the code from each module to produce the final target program optionally updates the listing files produced by the compiler and/or assembler adding the final absolute address information. carries out a complete type check across all modules examining global variables, functions (return type, parameter types and numbers, reentrant attributes, interrupt attributes, and memory model type) and structure and union member types to ensure total program integrity The linker will also construct a call tree of your C functions. It will use this to perform an overlay analysis of the local data areas of any non-reentrant functions, sharing memory wherever possible. It will report potential recursion of non-reentrant functions. At the same time, the parameter space for non-reentrant functions with variable numbers of arguments will be sized to the maximum reuired by any of the calls to that function. You can define multiple regions for both ROM and RAM to suit your target hardware and you can specifically locate named segments at any address you wish and define their order relative to each other. You can define up to 256 switchable banks of program memory and up to 256 switchable banks of xdata memory allowing you to address up to 16 MBytes of memory! The target program can be produced in a number of different formats including Intel hex, Intel OMF51, Motorola S' record, HP/Microtec IEEE695 format or as a binary rom image. No conversion utility has to be used - the linker directly outputs the program in the specified format. An optional link map will show the final location and sizes of all segments and the addresses of all global variables. 10

LIB LIBRARY MANAGER Instead of being used to create a final target program, the object modules produced by the compiler and assembler can be integrated into a library.

11 LIB LIBRARY MANAGER Instead of being used to create a final target program, the object modules produced by the compiler and assembler can be integrated into a library. The library manager performs the tasks of: combining object modules into a library adding modules to an existing library removing or extracting modules from an existing library listing the contents of a library The Library manager can be automatically invoked from the Embedded Development Studio to build a complete object code library. An object code library can then be specified at link time when building your program. The linker will search the library and extract modules from it as necessary to complete your program. MAKE MAKE UTILITY The MAKE utility simplifies the task of keeping object files, libraries and target programs up-to-date. It detects if any source or dependency files have changed since the last build and runs the appropriate tools (compiler, assembler, linker or library manager) to rebuild out-of-date files. It supports many advanced features including macros, inference rules, conditional inclusion and other preprocessing directives and in-line files with automatic temporary file creation. Although the Embedded Development Studio uses its own integrated routines to keep projects up-to-date, this stand-alone MAKE utility can be used to build projects from the command-line or from within another application. The Embedded Development Studio will automatically create a makefile which is fully compatible with this stand-alone MAKE utility. 11

12 ASSEMBLER RELOCATABLE MACRO CROSS ASSEMBLER High speed assembly to create relocatable object modules. Intel standard segment directives allow segments to be aligned to page and block boundaries, contained within a page or block, positioned at the highest in memory location or positioned above all other segments. Enhanced segment options to create switchable code and data banks. Intel standard assembler mnemonics Nestable macros with full argument passing Nestable conditional assembly Comprehensive range of assembler directives and pseudo ops. Complex expression evaluation with Intel standard operators Intel standard 8051 and 8052 predefined symbols Upper and lower case labels with up to 255 significant characters Upper and lower case opcode mnemonics Upper and lower case macro names with up to 255 significant characters Comprehensive error checking with descriptive error messages Debug output of source code information User definable listing format Run from the command line or from within the editor HOST SYSTEM REQUIREMENTS IBM compatible PC with an Intel Pentium or above running Windows 9x, Windows NT 4.0, Windows 2000 or Windows XP. Crossware Products is the business name of Crossware Limited. Registered address as above. Registered in England and Wales under company registration number CROSSWARE is a registered trademark of Crossware Associates. 12

CROSSWARE 8051DS Development Suite COMPONENTS

CROSSWARE 8051DS Development Suite COMPONENTS CROSSWARE 8051DS Crossware Products was established in September 1984 to fill an important and expanding niche in embedded development software. It released a C compiler and assembler for the 8051 microcontroller