cc5x - 31

(Parte 1 de 14)

CC5X

C Compiler for the PICmicro Devices

Version 3.1

User's Manual

B Knudsen Data Trondheim - Norway

CC5X C Compiler B Knudsen Data

This manual and the CC5X compiler is protected by Norwegian copyright laws and thus by corresponding copyright laws agreed internationally by mutual consent. The manual and the compiler may not be copied, partially or as a whole without the written consent from the author. The PDF-edition of the manual can be printed to paper for private or local use, but not for distribution. Modification of the manual or the compiler is strongly prohibited. All rights reserved.

LICENSE AGREEMENT: By using the CC5X compiler, you agree to be bound by this agreement. Only one person may use a licensed CC5X compiler at the same time. If more than one person want to use the compiler for each license, then this have to be done by some manual handshaking procedure (not electronic automated), for instance by exchanging this manual as a permission key. You may make backup copies of the software, and copy it to multiple computers. You may not distribute copies of the compiler to others. B Knudsen Data assumes no responsibility for errors or defects in this manual or in the compiler. This also applies to problems caused by such errors.

Copyright © B Knudsen Data, Trondheim, Norway, 1992 - 2000

This manual covers CC5X version 3.1 and related topics. New versions may contain changes without prior notice.

Microchip and PICmicro are trademarks of Microchip Technology Inc., Chandler, U.S.A.

The compiler has been carefully tested and debugged. It is, however, not possible to guarantee a 100 % error free product.

If the compiler generates application code bugs, it is almost always possible to rewrite the program slightly in order to avoid the bug. #pragma optimize can be used to avoid optimization bugs. Other #pragma statements are also useful.

Please report cases of bad generated code and other serious program errors.

1) Investigate and describe the problem. If possible, please provide a short code sample which demonstrates the problem. A fragment of the generated assembly file (use cut and paste) is normally enough. Alternatively a short and complete C program (10 - 100 lines). 2) This service is intended for difficult compiler problems (not application problems). 3) Language: English 4) State the compiler version. 5) Send your report to support@bknd.com or by fax to (+47) 73 96 51 84.

CC5X C Compiler B Knudsen Data

1 INTRODUCTION	7
1.1 SUPPORTED DEVICES	8
1.2 INSTALLATION AND SYSTEM REQUIREMENTS	8
Support for Long File Names	8
User Interface	8
1.3 MPLAB SUPPORT	9
1.4 SUMMARY OF DELIVERED FILES	9
1.5 SHORT PROGRAM EXAMPLE	10
1.6 DEFINING THE PICMICRO DEVICE	1
1.7 WHAT TO DO NEXT	12
2 VARIABLES	13
2.1 INFORMATION ON RAM ALLOCATION	13
2.2 DEFINING VARIABLES	13
Integer variables	14
Floating point	14
IEEE754 interoperability	15
Fixed point variables	16
Assigning variables to RAM addresses	17
Supported type modifiers	18
Local Variables	19
Temporary Variables	19
Arrays, structures and unions	20
Bitfields	20
Typedef	21
2.3 USING RAM BANKS	21
The bank type modifier	21
RAM Bank Selection Bits	2
Local user update regions	2
2.4 POINTERS	23
Pointer models	23
The 12 bit Core	24
The 14 bit core: the IRP bit	25
2.5 CONST DATA SUPPORT	26
Storing 14 bit data	27
Data of size 16 bit or more	27
Code pages	28
Merging data	28
Examples	28
3 SYNTAX	29
3.1 STATEMENTS	29
if statement	29
while statement	29
for statement	29
do statement	30
switch statement	30
break statement	30
continue statement	31
return statement	31
goto statement	31

CONTENTS 3.2 ASSIGNMENT AND CONDITIONS ....................................................................................................... 31

CC5X C Compiler B Knudsen Data

Special syntax examples	31
Conditions	32
Bit variables	32
Multiplication, division and modulo	3
Precedence of C operators	3
Mixed variable sizes are allowed	34
3.3 CONSTANTS	34
Constant Expressions	34
Enumeration	35
3.4 FUNCTIONS	35
Function return values	35
Parameters in function calls	35
Internal functions	35
3.5 TYPE CAST	36
3.6 ACCESSING PARTS OF A VARIABLE	37
3.7 C EXTENSIONS	37
3.8 PREDEFINED SYMBOLS	38
Automatically defined macros and symbols	39
3.9 UPWARD COMPATIBILITY	39
4 PREPROCESSOR DIRECTIVES	40
#define	40
#include	40
#undef	40
#if	40
#ifdef	41
#ifndef	41
#elif	41
#else	41
#endif	41
#error	41
#pragma	41
4.1 THE PRAGMA STATEMENT	41
#pragma asm2var 1	42
#pragma assert [/] <type> <text field>	42
#pragma assume *<pointer> in rambank <n>	42
#pragma bit <name> @ <N.B or variable[.B]>	42
#pragma cdata[ADDRESS] = <VXS>, .., <VXS>	42
#pragma char <name> @ <constant or variable>	43
#pragma chip [=] <device>	43
#pragma codepage [=] <0,1,2,3>	43
#pragma computedGoto [=] <0,1,2>	43
#pragma config <id> = <state> [, <id> = <state>]	43
#pragma config_def [=] <value>	4
#pragma library <0/1>	4
#pragma location [=] <0,1,2,3,->	4
#pragma optimize [=] [N:] <0,1>	4
#pragma origin [=] <n>	4
#pragma rambank [=] <0,1,2,3,->	45
#pragma rambase [=] <n>	45
#pragma ramdef <ra> : <rb> [MAPPING]	45
#pragma resetVector <n>	45
#pragma return[<n>] = <strings or constants>	45
#pragma stackLevels <n>	46
#pragma update_FSR [=] <0,1>	46

CC5X C Compiler B Knudsen Data

#pragma update_PAGE [=] <0,1>	46
#pragma update_RP [=] <0,1>	46
#pragma wideConstData [<N>]	47
4.2 PICMICRO CONFIGURATION	47
5 COMMAND LINE OPTIONS	48
5.1 OPTIONS ON A FILE	50
6 PROGRAM CODE	51
6.1 PROGRAM CODE PAGES	51
Another way of locating functions	51
The page type modifier	52
Page selection bits	52
6.2 SUBROUTINE CALL LEVEL CHECKING	52
Stack level checking when using interrupt	52
Recursive functions	53
6.3 INTERRUPTS	53
6.4 STARTUP AND TERMINATION CODE	54
Clearing ALL RAM locations	54
6.5 LIBRARY SUPPORT	5
Math libraries	5
Integer libraries	56
Fixed point libraries	57
Floating point libraries	58
Floating point library functions	59
Fast and compact inline operations	61
Using prototypes and multiple code pages	61
Fixed point example	62
Floating point example	62
How to save code	63
6.6 INLINE ASSEMBLY	63
Generating Single Instructions	67
6.7 OPTIMIZING THE CODE	68
Optimized Syntax	68
Peephole optimization	69
6.8 LINKER SUPPORT	70
Variables	70
Local variables	71
Header files	71
Using RAM banks	71
Bank bit updating	72
Functions	72
Using code pages	72
Interrupts	72
Call level checking	73
Computed goto	73
Recommendations when using MPLINK	73
MPLAB and MPASM support	74
The MPLINK script file	75
Example with 3 modules	7
6.9 THE CDATA STATEMENT	80
Storing EEPROM data	80
Using the cdata statement	81
7 DEBUGGING	83

5 7.1 COMPILATION ERRORS..................................................................................................................... 83

CC5X C Compiler B Knudsen Data

Error and warning details	84
Some common compilation problems	84
7.2 MPLAB DEBUGGING SUPPORT	84
ICD debugging	85
7.3 ASSERT STATEMENTS	85
7.4 DEBUGGING IN ANOTHER ENVIRONMENT	86
8 FILES PRODUCED	8
8.1 HEX FILE	8
8.2 ASSEMBLY OUTPUT FILE	8
8.3 VARIABLE FILE	89
8.4 LIST FILE	90
8.5 FUNCTION CALL STRUCTURE	90
9 APPLICATION NOTES	91
9.1 DELAYS	91
9.2 COMPUTED GOTO	92
Built in skip() function for computed goto	93
Computed Goto Regions	93
9.3 THE SWITCH STATEMENT	96
APPENDIX	97
A1 USING INTERRUPTS	97
A2 PREDEFINED REGISTER NAMES	98
A3 ASSEMBLY INSTRUCTIONS	98
Addition for the 14 bit core	9

CC5X C Compiler B Knudsen Data

1 INTRODUCTION

Welcome to the CC5X C compiler for the Microchip PICmicro family of microcontrollers. The CC5X compiler enables programming using a subset of the C language. Assembly is no longer required. The reason for moving to C is clear. Assembly language is generally hard to read and errors are easily produced.

C enables the following advantages compared to assembly: • Source code standardization

• Faster program development

• Improved source code readability

• Easier documentation

• Simplified maintenance

• Portable code

The CC5X compiler was designed to generate tight and optimized code. The optimizer automatically squeezes the code to a minimum. It is possible to write code that compiles into single instructions, but with C syntax. This means that the code can be optimized by rewriting C instead of rewriting assembly.

The design priority was not to provide full ANSI C support, but to enable best possible usage of the limited code and RAM resources. If the compiler generated less optimal code, this would force assembly to be used for parts of the code.

CC5X features

• Local and global variables of 1, 8, 16, 24 and 32 bits • Efficient reuse of local variable space

• Generates tight and optimized code

• Produces binary, assembly, list, COD, error, function outline and variable files

• Automatic updating of the page selection bits

• Automatic updating of the bank selection bits

• Enhanced and compact support of bit operations, including bit functions

• Floating and fixed point math up to 32 bit

• Math libraries including functions like sin(), log(), exp(), sqrt(), etc.

• Supports standard C constant data and strings in program memory (const)

• Automatic storing of compressed 7 bit data in PIC16F87X devices

• Pointer models of 8 and 16 bits, mixed sizes in same application allowed

• RAM and/or ROM pointers

• The size of single pointers can be automatically chosen by the compiler

• Linker support (MPLINK), interfaces with assembly (MPASM) modules

• Extended call level by using GOTO instead of CALL when possible

• Inserts links to "hidden" subroutines

• Access to all assembly instructions through corresponding C statements

(Parte 1 de 14)