+\f
+/* Support for converting target fp numbers into host DOUBLEST format. */
+
+/* XXX - This code should really be in libiberty/floatformat.c, however
+ configuration issues with libiberty made this very difficult to do in the
+ available time. */
+
+#include "floatformat.h"
+#include <math.h> /* ldexp */
+
+/* The odds that CHAR_BIT will be anything but 8 are low enough that I'm not
+ going to bother with trying to muck around with whether it is defined in
+ a system header, what we do if not, etc. */
+#define FLOATFORMAT_CHAR_BIT 8
+
+static unsigned long get_field (unsigned char *,
+ enum floatformat_byteorders,
+ unsigned int, unsigned int, unsigned int);
+
+/* Extract a field which starts at START and is LEN bytes long. DATA and
+ TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
+static unsigned long
+get_field (unsigned char *data, enum floatformat_byteorders order,
+ unsigned int total_len, unsigned int start, unsigned int len)
+{
+ unsigned long result;
+ unsigned int cur_byte;
+ int cur_bitshift;
+
+ /* Start at the least significant part of the field. */
+ if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ {
+ /* We start counting from the other end (i.e, from the high bytes
+ rather than the low bytes). As such, we need to be concerned
+ with what happens if bit 0 doesn't start on a byte boundary.
+ I.e, we need to properly handle the case where total_len is
+ not evenly divisible by 8. So we compute ``excess'' which
+ represents the number of bits from the end of our starting
+ byte needed to get to bit 0. */
+ int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT);
+ cur_byte = (total_len / FLOATFORMAT_CHAR_BIT)
+ - ((start + len + excess) / FLOATFORMAT_CHAR_BIT);
+ cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT)
+ - FLOATFORMAT_CHAR_BIT;
+ }
+ else
+ {
+ cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT;
+ cur_bitshift =
+ ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT;
+ }
+ if (cur_bitshift > -FLOATFORMAT_CHAR_BIT)
+ result = *(data + cur_byte) >> (-cur_bitshift);
+ else
+ result = 0;
+ cur_bitshift += FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ ++cur_byte;
+ else
+ --cur_byte;
+
+ /* Move towards the most significant part of the field. */
+ while (cur_bitshift < len)
+ {
+ result |= (unsigned long)*(data + cur_byte) << cur_bitshift;
+ cur_bitshift += FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ ++cur_byte;
+ else
+ --cur_byte;
+ }
+ if (len < sizeof(result) * FLOATFORMAT_CHAR_BIT)
+ /* Mask out bits which are not part of the field */
+ result &= ((1UL << len) - 1);
+ return result;
+}
+
+/* Convert from FMT to a DOUBLEST.
+ FROM is the address of the extended float.
+ Store the DOUBLEST in *TO. */
+
+void
+floatformat_to_doublest (const struct floatformat *fmt, char *from,
+ DOUBLEST *to)
+{
+ unsigned char *ufrom = (unsigned char *) from;
+ DOUBLEST dto;
+ long exponent;
+ unsigned long mant;
+ unsigned int mant_bits, mant_off;
+ int mant_bits_left;
+ int special_exponent; /* It's a NaN, denorm or zero */
+
+ /* If the mantissa bits are not contiguous from one end of the
+ mantissa to the other, we need to make a private copy of the
+ source bytes that is in the right order since the unpacking
+ algorithm assumes that the bits are contiguous.
+
+ Swap the bytes individually rather than accessing them through
+ "long *" since we have no guarantee that they start on a long
+ alignment, and also sizeof(long) for the host could be different
+ than sizeof(long) for the target. FIXME: Assumes sizeof(long)
+ for the target is 4. */
+
+ if (fmt->byteorder == floatformat_littlebyte_bigword)
+ {
+ static unsigned char *newfrom;
+ unsigned char *swapin, *swapout;
+ int longswaps;
+
+ longswaps = fmt->totalsize / FLOATFORMAT_CHAR_BIT;
+ longswaps >>= 3;
+
+ if (newfrom == NULL)
+ {
+ newfrom = (unsigned char *) xmalloc (fmt->totalsize);
+ }
+ swapout = newfrom;
+ swapin = ufrom;
+ ufrom = newfrom;
+ while (longswaps-- > 0)
+ {
+ /* This is ugly, but efficient */
+ *swapout++ = swapin[4];
+ *swapout++ = swapin[5];
+ *swapout++ = swapin[6];
+ *swapout++ = swapin[7];
+ *swapout++ = swapin[0];
+ *swapout++ = swapin[1];
+ *swapout++ = swapin[2];
+ *swapout++ = swapin[3];
+ swapin += 8;
+ }
+ }
+
+ exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize,
+ fmt->exp_start, fmt->exp_len);
+ /* Note that if exponent indicates a NaN, we can't really do anything useful
+ (not knowing if the host has NaN's, or how to build one). So it will
+ end up as an infinity or something close; that is OK. */
+
+ mant_bits_left = fmt->man_len;
+ mant_off = fmt->man_start;
+ dto = 0.0;
+
+ special_exponent = exponent == 0 || exponent == fmt->exp_nan;
+
+/* Don't bias NaNs. Use minimum exponent for denorms. For simplicity,
+ we don't check for zero as the exponent doesn't matter. */
+ if (!special_exponent)
+ exponent -= fmt->exp_bias;
+ else if (exponent == 0)
+ exponent = 1 - fmt->exp_bias;
+
+ /* Build the result algebraically. Might go infinite, underflow, etc;
+ who cares. */
+
+/* If this format uses a hidden bit, explicitly add it in now. Otherwise,
+ increment the exponent by one to account for the integer bit. */
+
+ if (!special_exponent)
+ {
+ if (fmt->intbit == floatformat_intbit_no)
+ dto = ldexp (1.0, exponent);
+ else
+ exponent++;
+ }
+
+ while (mant_bits_left > 0)
+ {
+ mant_bits = min (mant_bits_left, 32);
+
+ mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
+ mant_off, mant_bits);
+
+ dto += ldexp ((double) mant, exponent - mant_bits);
+ exponent -= mant_bits;
+ mant_off += mant_bits;
+ mant_bits_left -= mant_bits;
+ }
+
+ /* Negate it if negative. */
+ if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1))
+ dto = -dto;
+ *to = dto;
+}
+\f
+static void put_field (unsigned char *, enum floatformat_byteorders,
+ unsigned int,
+ unsigned int, unsigned int, unsigned long);
+
+/* Set a field which starts at START and is LEN bytes long. DATA and
+ TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
+static void
+put_field (unsigned char *data, enum floatformat_byteorders order,
+ unsigned int total_len, unsigned int start, unsigned int len,
+ unsigned long stuff_to_put)
+{
+ unsigned int cur_byte;
+ int cur_bitshift;
+
+ /* Start at the least significant part of the field. */
+ if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ {
+ int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT);
+ cur_byte = (total_len / FLOATFORMAT_CHAR_BIT)
+ - ((start + len + excess) / FLOATFORMAT_CHAR_BIT);
+ cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT)
+ - FLOATFORMAT_CHAR_BIT;
+ }
+ else
+ {
+ cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT;
+ cur_bitshift =
+ ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT;
+ }
+ if (cur_bitshift > -FLOATFORMAT_CHAR_BIT)
+ {
+ *(data + cur_byte) &=
+ ~(((1 << ((start + len) % FLOATFORMAT_CHAR_BIT)) - 1)
+ << (-cur_bitshift));
+ *(data + cur_byte) |=
+ (stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift);
+ }
+ cur_bitshift += FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ ++cur_byte;
+ else
+ --cur_byte;
+
+ /* Move towards the most significant part of the field. */
+ while (cur_bitshift < len)
+ {
+ if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT)
+ {
+ /* This is the last byte. */
+ *(data + cur_byte) &=
+ ~((1 << (len - cur_bitshift)) - 1);
+ *(data + cur_byte) |= (stuff_to_put >> cur_bitshift);
+ }
+ else
+ *(data + cur_byte) = ((stuff_to_put >> cur_bitshift)
+ & ((1 << FLOATFORMAT_CHAR_BIT) - 1));
+ cur_bitshift += FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ ++cur_byte;
+ else
+ --cur_byte;
+ }
+}
+
+#ifdef HAVE_LONG_DOUBLE
+/* Return the fractional part of VALUE, and put the exponent of VALUE in *EPTR.
+ The range of the returned value is >= 0.5 and < 1.0. This is equivalent to
+ frexp, but operates on the long double data type. */
+
+static long double ldfrexp (long double value, int *eptr);
+
+static long double
+ldfrexp (long double value, int *eptr)
+{
+ long double tmp;
+ int exp;
+
+ /* Unfortunately, there are no portable functions for extracting the exponent
+ of a long double, so we have to do it iteratively by multiplying or dividing
+ by two until the fraction is between 0.5 and 1.0. */