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New shift module, comment fixes

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git-svn-id: svn://svn.cc65.org/cc65/trunk@2636 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2003-11-11 09:41:07 +00:00
parent 1db1c7cabc
commit 7e9b389428
6 changed files with 218 additions and 2 deletions
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2
src/common/addrsize.c
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@ -6,7 +6,7 @@
/* */ /* */
/* */ /* */
/* */ /* */
/* (C) 1998-2003 Ullrich von Bassewitz */ /* (C) 2003 Ullrich von Bassewitz */
/* Römerstraße 52 */ /* Römerstraße 52 */
/* D-70794 Filderstadt */ /* D-70794 Filderstadt */
/* EMail: uz@cc65.org */ /* EMail: uz@cc65.org */

2
src/common/addrsize.h
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@ -6,7 +6,7 @@
/* */ /* */
/* */ /* */
/* */ /* */
/* (C) 1998-2003 Ullrich von Bassewitz */ /* (C) 2003 Ullrich von Bassewitz */
/* Römerstraße 52 */ /* Römerstraße 52 */
/* D-70794 Filderstadt */ /* D-70794 Filderstadt */
/* EMail: uz@cc65.org */ /* EMail: uz@cc65.org */

1
src/common/make/gcc.mak
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@ -29,6 +29,7 @@ OBJS = abend.o \
searchpath.o \ searchpath.o \
segdefs.o \ segdefs.o \
segnames.o \ segnames.o \
shift.o \
strbuf.o \ strbuf.o \
strpool.o \ strpool.o \
strutil.o \ strutil.o \

1
src/common/make/watcom.mak
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@ -74,6 +74,7 @@ OBJS = abend.obj \
searchpath.obj \ searchpath.obj \
segdefs.obj \ segdefs.obj \
segnames.obj \ segnames.obj \
shift.obj \
strbuf.obj \ strbuf.obj \
strpool.obj \ strpool.obj \
strutil.obj \ strutil.obj \

130
src/common/shift.c Normal file
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@ -0,0 +1,130 @@
/*****************************************************************************/
/* */
/* shift.c */
/* */
/* Safe shift routines */
/* */
/* */
/* */
/* (C) 2003 Ullrich von Bassewitz */
/* Römerstraße 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
/* According to the C standard, shifting a data type by the number of bits it
* has causes undefined behaviour. So
*
* unsigned long l = 1;
* unsigned u =32;
* l <<= u;
*
* maybe illegal. The functions in this module behave safely in this respect,
* and they use proper casting to distinguish signed from unsigned shifts.
* They are not a general purpose replacement for the shift operator!
*/
#include <limits.h>
/* common */
#include "shift.h"
/*****************************************************************************/
/* Code */
/*****************************************************************************/
long asl_l (long l, unsigned count)
/* Arithmetic shift left l by count. */
{
while (1) {
if (count >= CHAR_BIT * sizeof (l)) {
l <<= (CHAR_BIT * sizeof (l) - 1);
count -= (CHAR_BIT * sizeof (l) - 1);
} else {
l <<= count;
break;
}
}
return l;
}
long asr_l (long l, unsigned count)
/* Arithmetic shift right l by count */
{
while (1) {
if (count >= CHAR_BIT * sizeof (l)) {
l >>= (CHAR_BIT * sizeof (l) - 1);
count -= (CHAR_BIT * sizeof (l) - 1);
} else {
l >>= count;
break;
}
}
return l;
}
unsigned long shl_l (unsigned long l, unsigned count)
/* Logical shift left l by count */
{
while (1) {
if (count >= CHAR_BIT * sizeof (l)) {
l <<= (CHAR_BIT * sizeof (l) - 1);
count -= (CHAR_BIT * sizeof (l) - 1);
} else {
l <<= count;
break;
}
}
return l;
}
unsigned long shr_l (unsigned long l, unsigned count)
/* Logical shift right l by count */
{
while (1) {
if (count >= CHAR_BIT * sizeof (l)) {
l >>= (CHAR_BIT * sizeof (l) - 1);
count -= (CHAR_BIT * sizeof (l) - 1);
} else {
l >>= count;
break;
}
}
return l;
}

84
src/common/shift.h Normal file
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@ -0,0 +1,84 @@
/*****************************************************************************/
/* */
/* shift.h */
/* */
/* Safe shift routines */
/* */
/* */
/* */
/* (C) 2003 Ullrich von Bassewitz */
/* Römerstraße 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
/* According to the C standard, shifting a data type by the number of bits it
* has causes undefined behaviour. So
*
* unsigned long l = 1;
* unsigned u =32;
* l <<= u;
*
* maybe illegal. The functions in this module behave safely in this respect,
* and they use proper casting to distinguish signed from unsigned shifts.
* They are not a general purpose replacement for the shift operator!
*/
#ifndef SHIFT_H
#define SHIFT_H
#include <limits.h>
/*****************************************************************************/
/* Code */
/*****************************************************************************/
long asl_l (long l, unsigned count);
/* Arithmetic shift left l by count. */
long asr_l (long l, unsigned count);
/* Arithmetic shift right l by count */
unsigned long shl_l (unsigned long l, unsigned count);
/* Logical shift left l by count */
unsigned long shr_l (unsigned long l, unsigned count);
/* Logical shift right l by count */
/* End of shift.h */
#endif