mirror of https://github.com/elliotnunn/wedge.git
104 lines
3.9 KiB
C
104 lines
3.9 KiB
C
/*
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File: printf.h
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Copyright (C) 2004 Kustaa Nyholm
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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This library is realy just two files: 'printf.h' and 'printf.c'.
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They provide a simple and small (+200 loc) printf functionality to
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be used in embedded systems.
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I've found them so usefull in debugging that I do not bother with a
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debugger at all.
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They are distributed in source form, so to use them, just compile them
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into your project.
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Two printf variants are provided: printf and sprintf.
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The formats supported by this implementation are: 'd' 'u' 'c' 's' 'x' 'X'.
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Zero padding and field width are also supported.
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If the library is compiled with 'PRINTF_SUPPORT_LONG' defined then the
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long specifier is also
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supported. Note that this will pull in some long math routines (pun intended!)
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and thus make your executable noticably longer.
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The memory foot print of course depends on the target cpu, compiler and
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compiler options, but a rough guestimate (based on a H8S target) is about
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1.4 kB for code and some twenty 'int's and 'char's, say 60 bytes of stack space.
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Not too bad. Your milage may vary. By hacking the source code you can
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get rid of some hunred bytes, I'm sure, but personally I feel the balance of
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functionality and flexibility versus code size is close to optimal for
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many embedded systems.
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To use the printf you need to supply your own character output function,
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something like :
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void putc ( void* p, char c)
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{
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while (!SERIAL_PORT_EMPTY) ;
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SERIAL_PORT_TX_REGISTER = c;
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}
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Before you can call printf you need to initialize it to use your
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character output function with something like:
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init_printf(NULL,putc);
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Notice the 'NULL' in 'init_printf' and the parameter 'void* p' in 'putc',
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the NULL (or any pointer) you pass into the 'init_printf' will eventually be
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passed to your 'putc' routine. This allows you to pass some storage space (or
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anything realy) to the character output function, if necessary.
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This is not often needed but it was implemented like that because it made
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implementing the sprintf function so neat (look at the source code).
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The code is re-entrant, except for the 'init_printf' function, so it
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is safe to call it from interupts too, although this may result in mixed output.
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If you rely on re-entrancy, take care that your 'putc' function is re-entrant!
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The printf and sprintf functions are actually macros that translate to
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'tfp_printf' and 'tfp_sprintf'. This makes it possible
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to use them along with 'stdio.h' printf's in a single source file.
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You just need to undef the names before you include the 'stdio.h'.
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Note that these are not function like macros, so if you have variables
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or struct members with these names, things will explode in your face.
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Without variadic macros this is the best we can do to wrap these
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fucnction. If it is a problem just give up the macros and use the
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functions directly or rename them.
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For further details see source code.
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regs Kusti, 23.10.2004
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*/
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#ifndef __TFP_PRINTF__
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#define __TFP_PRINTF__
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#include <stdarg.h>
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// These barely match the prototypes in stdio.h
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extern int printf(char *fmt, ...);
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extern void *memmove(void *dest, void *src, unsigned int n);
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extern void *memcpy(void *dest, void *src, unsigned int n);
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extern void *memset(void *dest, int v, unsigned int n);
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#endif
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