};
\f
-/* IEEE extended double precision format. This comes in three
- flavors: Intel's as a 12 byte image, Intel's as a 16 byte image,
- and Motorola's. */
-
-static void encode_ieee_extended (const struct real_format *fmt,
- long *, const REAL_VALUE_TYPE *);
-static void decode_ieee_extended (const struct real_format *,
- REAL_VALUE_TYPE *, const long *);
-
-static void encode_ieee_extended_128 (const struct real_format *fmt,
- long *, const REAL_VALUE_TYPE *);
-static void decode_ieee_extended_128 (const struct real_format *,
- REAL_VALUE_TYPE *, const long *);
-
+/* IEEE extended real format. This comes in three flavors: Intel's as
+ a 12 byte image, Intel's as a 16 byte image, and Motorola's. Intel
+ 12- and 16-byte images may be big- or little endian; Motorola's is
+ always big endian. */
+
+/* Helper subroutine which converts from the internal format to the
+ 12-byte little-endian Intel format. Functions below adjust this
+ for the other possible formats. */
static void
encode_ieee_extended (const struct real_format *fmt, long *buf,
const REAL_VALUE_TYPE *r)
abort ();
}
+ buf[0] = sig_lo, buf[1] = sig_hi, buf[2] = image_hi;
+}
+
+/* Convert from the internal format to the 12-byte Motorola format
+ for an IEEE extended real. */
+static void
+encode_ieee_extended_motorola (const struct real_format *fmt, long *buf,
+ const REAL_VALUE_TYPE *r)
+{
+ long intermed[3];
+ encode_ieee_extended (fmt, intermed, r);
+
+ /* Motorola chips are assumed always to be big-endian. Also, the
+ padding in a Motorola extended real goes between the exponent and
+ the mantissa. At this point the mantissa is entirely within
+ elements 0 and 1 of intermed, and the exponent entirely within
+ element 2, so all we have to do is swap the order around, and
+ shift element 2 left 16 bits. */
+ buf[0] = intermed[2] << 16;
+ buf[1] = intermed[1];
+ buf[2] = intermed[0];
+}
+
+/* Convert from the internal format to the 12-byte Intel format for
+ an IEEE extended real. */
+static void
+encode_ieee_extended_intel_96 (const struct real_format *fmt, long *buf,
+ const REAL_VALUE_TYPE *r)
+{
if (FLOAT_WORDS_BIG_ENDIAN)
- buf[0] = image_hi << 16, buf[1] = sig_hi, buf[2] = sig_lo;
+ {
+ /* All the padding in an Intel-format extended real goes at the high
+ end, which in this case is after the mantissa, not the exponent.
+ Therefore we must shift everything down 16 bits. */
+ long intermed[3];
+ encode_ieee_extended (fmt, intermed, r);
+ buf[0] = ((intermed[2] << 16) | ((unsigned long)(intermed[1] & 0xFFFF0000) >> 16));
+ buf[1] = ((intermed[1] << 16) | ((unsigned long)(intermed[0] & 0xFFFF0000) >> 16));
+ buf[2] = (intermed[0] << 16);
+ }
else
- buf[0] = sig_lo, buf[1] = sig_hi, buf[2] = image_hi;
+ /* encode_ieee_extended produces what we want directly. */
+ encode_ieee_extended (fmt, buf, r);
}
+/* Convert from the internal format to the 16-byte Intel format for
+ an IEEE extended real. */
static void
-encode_ieee_extended_128 (const struct real_format *fmt, long *buf,
- const REAL_VALUE_TYPE *r)
+encode_ieee_extended_intel_128 (const struct real_format *fmt, long *buf,
+ const REAL_VALUE_TYPE *r)
{
- buf[3 * !FLOAT_WORDS_BIG_ENDIAN] = 0;
- encode_ieee_extended (fmt, buf+!!FLOAT_WORDS_BIG_ENDIAN, r);
+ /* All the padding in an Intel-format extended real goes at the high end. */
+ encode_ieee_extended_intel_96 (fmt, buf, r);
+ buf[3] = 0;
}
+/* As above, we have a helper function which converts from 12-byte
+ little-endian Intel format to internal format. Functions below
+ adjust for the other possible formats. */
static void
decode_ieee_extended (const struct real_format *fmt, REAL_VALUE_TYPE *r,
const long *buf)
bool sign;
int exp;
- if (FLOAT_WORDS_BIG_ENDIAN)
- image_hi = buf[0] >> 16, sig_hi = buf[1], sig_lo = buf[2];
- else
- sig_lo = buf[0], sig_hi = buf[1], image_hi = buf[2];
+ sig_lo = buf[0], sig_hi = buf[1], image_hi = buf[2];
sig_lo &= 0xffffffff;
sig_hi &= 0xffffffff;
image_hi &= 0xffffffff;
}
}
+/* Convert from the internal format to the 12-byte Motorola format
+ for an IEEE extended real. */
+static void
+decode_ieee_extended_motorola (const struct real_format *fmt, REAL_VALUE_TYPE *r,
+ const long *buf)
+{
+ long intermed[3];
+
+ /* Motorola chips are assumed always to be big-endian. Also, the
+ padding in a Motorola extended real goes between the exponent and
+ the mantissa; remove it. */
+ intermed[0] = buf[2];
+ intermed[1] = buf[1];
+ intermed[2] = (unsigned long)buf[0] >> 16;
+
+ decode_ieee_extended (fmt, r, intermed);
+}
+
+/* Convert from the internal format to the 12-byte Intel format for
+ an IEEE extended real. */
+static void
+decode_ieee_extended_intel_96 (const struct real_format *fmt, REAL_VALUE_TYPE *r,
+ const long *buf)
+{
+ if (FLOAT_WORDS_BIG_ENDIAN)
+ {
+ /* All the padding in an Intel-format extended real goes at the high
+ end, which in this case is after the mantissa, not the exponent.
+ Therefore we must shift everything up 16 bits. */
+ long intermed[3];
+
+ intermed[0] = (((unsigned long)buf[2] >> 16) | (buf[1] << 16));
+ intermed[1] = (((unsigned long)buf[1] >> 16) | (buf[0] << 16));
+ intermed[2] = ((unsigned long)buf[0] >> 16);
+
+ decode_ieee_extended (fmt, r, intermed);
+ }
+ else
+ /* decode_ieee_extended produces what we want directly. */
+ decode_ieee_extended (fmt, r, buf);
+}
+
+/* Convert from the internal format to the 16-byte Intel format for
+ an IEEE extended real. */
static void
-decode_ieee_extended_128 (const struct real_format *fmt, REAL_VALUE_TYPE *r,
- const long *buf)
+decode_ieee_extended_intel_128 (const struct real_format *fmt, REAL_VALUE_TYPE *r,
+ const long *buf)
{
- decode_ieee_extended (fmt, r, buf+!!FLOAT_WORDS_BIG_ENDIAN);
+ /* All the padding in an Intel-format extended real goes at the high end. */
+ decode_ieee_extended_intel_96 (fmt, r, buf);
}
const struct real_format ieee_extended_motorola_format =
{
- encode_ieee_extended,
- decode_ieee_extended,
+ encode_ieee_extended_motorola,
+ decode_ieee_extended_motorola,
2,
1,
64,
const struct real_format ieee_extended_intel_96_format =
{
- encode_ieee_extended,
- decode_ieee_extended,
+ encode_ieee_extended_intel_96,
+ decode_ieee_extended_intel_96,
2,
1,
64,
const struct real_format ieee_extended_intel_128_format =
{
- encode_ieee_extended_128,
- decode_ieee_extended_128,
+ encode_ieee_extended_intel_128,
+ decode_ieee_extended_intel_128,
2,
1,
64,
to 53 bits instead of 64, e.g. FreeBSD. */
const struct real_format ieee_extended_intel_96_round_53_format =
{
- encode_ieee_extended,
- decode_ieee_extended,
+ encode_ieee_extended_intel_96,
+ decode_ieee_extended_intel_96,
2,
1,
53,
OSDN Git Service
