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[RFC] Add support for VAX floating-point types
- From: Mark Kettenis <mark dot kettenis at xs4all dot nl>
- To: gdb-patches at sourceware dot org
- Date: Mon, 22 Aug 2005 00:09:25 +0200 (CEST)
- Subject: [RFC] Add support for VAX floating-point types
OK, I admit it, all this work on VAX is pointless ... but fun ;-).
And it actually improves the code too ;-). This patch depends on the
libiberty patch I just sent out. Any objections? If not I'll check
this in next weekend if possible.
Mark
Index: ChangeLog
from Mark Kettenis <kettenis@gnu.org>
* doublest.c (floatformat_normalize_byteorder): Handle
floatformat_vax.
(convert_doublest_to_floatformat): Use
floatformat_normalize_byteorder to swap bytes if necessary.
Index: doublest.c
===================================================================
RCS file: /cvs/src/src/gdb/doublest.c,v
retrieving revision 1.26
diff -u -p -r1.26 doublest.c
--- doublest.c 21 Aug 2005 16:53:05 -0000 1.26
+++ doublest.c 21 Aug 2005 22:04:40 -0000
@@ -1,8 +1,8 @@
/* Floating point routines for GDB, the GNU debugger.
Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
- 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005 Free Software
- Foundation, Inc.
+ 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005
+ Free Software Foundation, Inc.
This file is part of GDB.
@@ -110,9 +110,10 @@ get_field (const bfd_byte *data, enum fl
return result;
}
-/* Normalize the byte order of FROM into TO. If no normalization is needed
- then FMT->byteorder is returned and TO is not changed; otherwise the format
- of the normalized form in TO is returned. */
+/* Normalize the byte order of FROM into TO. If no normalization is
+ needed then FMT->byteorder is returned and TO is not changed;
+ otherwise the format of the normalized form in TO is returned. */
+
static enum floatformat_byteorders
floatformat_normalize_byteorder (const struct floatformat *fmt,
const void *from, void *to)
@@ -125,23 +126,40 @@ floatformat_normalize_byteorder (const s
|| fmt->byteorder == floatformat_big)
return fmt->byteorder;
- gdb_assert (fmt->byteorder == floatformat_littlebyte_bigword);
-
words = fmt->totalsize / FLOATFORMAT_CHAR_BIT;
words >>= 2;
swapout = (unsigned char *)to;
swapin = (const unsigned char *)from;
- while (words-- > 0)
+ if (fmt->byteorder == floatformat_vax)
+ {
+ while (words-- > 0)
+ {
+ *swapout++ = swapin[1];
+ *swapout++ = swapin[0];
+ *swapout++ = swapin[3];
+ *swapout++ = swapin[2];
+ swapin += 4;
+ }
+ /* This may look weird, since VAX is little-endian, but it is
+ easier to translate to big-endian than to little-endian. */
+ return floatformat_big;
+ }
+ else
{
- *swapout++ = swapin[3];
- *swapout++ = swapin[2];
- *swapout++ = swapin[1];
- *swapout++ = swapin[0];
- swapin += 4;
+ gdb_assert (fmt->byteorder == floatformat_littlebyte_bigword);
+
+ while (words-- > 0)
+ {
+ *swapout++ = swapin[3];
+ *swapout++ = swapin[2];
+ *swapout++ = swapin[1];
+ *swapout++ = swapin[0];
+ swapin += 4;
+ }
+ return floatformat_big;
}
- return floatformat_big;
}
/* Convert from FMT to a DOUBLEST.
@@ -337,14 +355,13 @@ ldfrexp (long double value, int *eptr)
#endif /* HAVE_LONG_DOUBLE */
-/* The converse: convert the DOUBLEST *FROM to an extended float
- and store where TO points. Neither FROM nor TO have any alignment
+/* The converse: convert the DOUBLEST *FROM to an extended float and
+ store where TO points. Neither FROM nor TO have any alignment
restrictions. */
static void
convert_doublest_to_floatformat (CONST struct floatformat *fmt,
- const DOUBLEST *from,
- void *to)
+ const DOUBLEST *from, void *to)
{
DOUBLEST dfrom;
int exponent;
@@ -353,10 +370,14 @@ convert_doublest_to_floatformat (CONST s
int mant_bits_left;
unsigned char *uto = (unsigned char *) to;
enum floatformat_byteorders order = fmt->byteorder;
+ unsigned char newto[FLOATFORMAT_LARGEST_BYTES];
- if (order == floatformat_littlebyte_bigword)
+ if (order != floatformat_little)
order = floatformat_big;
+ if (order != fmt->byteorder)
+ uto = newto;
+
memcpy (&dfrom, from, sizeof (dfrom));
memset (uto, 0, (fmt->totalsize + FLOATFORMAT_CHAR_BIT - 1)
/ FLOATFORMAT_CHAR_BIT);
@@ -447,24 +468,7 @@ convert_doublest_to_floatformat (CONST s
finalize_byteorder:
/* Do we need to byte-swap the words in the result? */
if (order != fmt->byteorder)
- {
- int words;
- unsigned char *curword = uto;
- unsigned char tmp;
-
- words = fmt->totalsize / FLOATFORMAT_CHAR_BIT;
- words >>= 2;
- while (words-- > 0)
- {
- tmp = curword[0];
- curword[0] = curword[3];
- curword[3] = tmp;
- tmp = curword[1];
- curword[1] = curword[2];
- curword[2] = tmp;
- curword += 4;
- }
- }
+ floatformat_normalize_byteorder (fmt, newto, to);
}
/* Check if VAL (which is assumed to be a floating point number whose