--- /dev/null
+
+/* atof_tahoe.c - turn a string into a Tahoe floating point number
+ Copyright (C) 1987 Free Software Foundation, Inc.
+ */
+
+/* This is really a simplified version of atof_vax.c. I glommed it wholesale
+ and then shaved it down. I don't even know how it works. (Don't you find
+ my honesty refreshing? bowen@cs.Buffalo.EDU (Devon E Bowen)
+
+ I don't allow uppercase letters in the precision descrpitors. Ie 'f' and
+ 'd' are allowed but 'F' and 'D' aren't */
+
+#include "as.h"
+
+/* Precision in LittleNums. */
+#define MAX_PRECISION (4)
+#define D_PRECISION (4)
+#define F_PRECISION (2)
+
+/* Precision in chars. */
+#define D_PRECISION_CHARS (8)
+#define F_PRECISION_CHARS (4)
+
+/* Length in LittleNums of guard bits. */
+#define GUARD (2)
+
+static const long int mask[] =
+{
+ 0x00000000,
+ 0x00000001,
+ 0x00000003,
+ 0x00000007,
+ 0x0000000f,
+ 0x0000001f,
+ 0x0000003f,
+ 0x0000007f,
+ 0x000000ff,
+ 0x000001ff,
+ 0x000003ff,
+ 0x000007ff,
+ 0x00000fff,
+ 0x00001fff,
+ 0x00003fff,
+ 0x00007fff,
+ 0x0000ffff,
+ 0x0001ffff,
+ 0x0003ffff,
+ 0x0007ffff,
+ 0x000fffff,
+ 0x001fffff,
+ 0x003fffff,
+ 0x007fffff,
+ 0x00ffffff,
+ 0x01ffffff,
+ 0x03ffffff,
+ 0x07ffffff,
+ 0x0fffffff,
+ 0x1fffffff,
+ 0x3fffffff,
+ 0x7fffffff,
+ 0xffffffff
+};
+\f
+
+/* Shared between flonum_gen2tahoe and next_bits */
+static int bits_left_in_littlenum;
+static LITTLENUM_TYPE *littlenum_pointer;
+static LITTLENUM_TYPE *littlenum_end;
+
+#if __STDC__ == 1
+
+int flonum_gen2tahoe (int format_letter, FLONUM_TYPE * f, LITTLENUM_TYPE * words);
+
+#else /* not __STDC__ */
+
+int flonum_gen2tahoe ();
+
+#endif /* not __STDC__ */
+
+
+static int
+next_bits (number_of_bits)
+ int number_of_bits;
+{
+ int return_value;
+
+ if (littlenum_pointer < littlenum_end)
+ return 0;
+ if (number_of_bits >= bits_left_in_littlenum)
+ {
+ return_value = mask[bits_left_in_littlenum] & *littlenum_pointer;
+ number_of_bits -= bits_left_in_littlenum;
+ return_value <<= number_of_bits;
+ bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits;
+ littlenum_pointer--;
+ if (littlenum_pointer >= littlenum_end)
+ return_value |= ((*littlenum_pointer) >> (bits_left_in_littlenum)) &
+ mask[number_of_bits];
+ }
+ else
+ {
+ bits_left_in_littlenum -= number_of_bits;
+ return_value = mask[number_of_bits] &
+ ((*littlenum_pointer) >> bits_left_in_littlenum);
+ }
+ return (return_value);
+}
+
+static void
+make_invalid_floating_point_number (words)
+ LITTLENUM_TYPE *words;
+{
+ *words = 0x8000; /* Floating Reserved Operand Code */
+}
+\f
+static int /* 0 means letter is OK. */
+what_kind_of_float (letter, precisionP, exponent_bitsP)
+ char letter; /* In: lowercase please. What kind of float? */
+ int *precisionP; /* Number of 16-bit words in the float. */
+ long int *exponent_bitsP; /* Number of exponent bits. */
+{
+ int retval; /* 0: OK. */
+
+ retval = 0;
+ switch (letter)
+ {
+ case 'f':
+ *precisionP = F_PRECISION;
+ *exponent_bitsP = 8;
+ break;
+
+ case 'd':
+ *precisionP = D_PRECISION;
+ *exponent_bitsP = 8;
+ break;
+
+ default:
+ retval = 69;
+ break;
+ }
+ return (retval);
+}
+\f
+/***********************************************************************\
+* *
+* Warning: this returns 16-bit LITTLENUMs, because that is *
+* what the VAX thinks in. It is up to the caller to figure *
+* out any alignment problems and to conspire for the bytes/word *
+* to be emitted in the right order. Bigendians beware! *
+* *
+\***********************************************************************/
+
+char * /* Return pointer past text consumed. */
+atof_tahoe (str, what_kind, words)
+ char *str; /* Text to convert to binary. */
+ char what_kind; /* 'd', 'f', 'g', 'h' */
+ LITTLENUM_TYPE *words; /* Build the binary here. */
+{
+ FLONUM_TYPE f;
+ LITTLENUM_TYPE bits[MAX_PRECISION + MAX_PRECISION + GUARD];
+ /* Extra bits for zeroed low-order bits. */
+ /* The 1st MAX_PRECISION are zeroed, */
+ /* the last contain flonum bits. */
+ char *return_value;
+ int precision; /* Number of 16-bit words in the format. */
+ long int exponent_bits;
+
+ return_value = str;
+ f.low = bits + MAX_PRECISION;
+ f.high = NULL;
+ f.leader = NULL;
+ f.exponent = NULL;
+ f.sign = '\0';
+
+ if (what_kind_of_float (what_kind, &precision, &exponent_bits))
+ {
+ return_value = NULL; /* We lost. */
+ make_invalid_floating_point_number (words);
+ }
+ if (return_value)
+ {
+ memset (bits, '\0', sizeof (LITTLENUM_TYPE) * MAX_PRECISION);
+
+ /* Use more LittleNums than seems */
+ /* necessary: the highest flonum may have */
+ /* 15 leading 0 bits, so could be useless. */
+ f.high = f.low + precision - 1 + GUARD;
+
+ if (atof_generic (&return_value, ".", "eE", &f))
+ {
+ make_invalid_floating_point_number (words);
+ return_value = NULL; /* we lost */
+ }
+ else
+ {
+ if (flonum_gen2tahoe (what_kind, &f, words))
+ {
+ return_value = NULL;
+ }
+ }
+ }
+ return (return_value);
+}
+\f
+/*
+ * In: a flonum, a Tahoe floating point format.
+ * Out: a Tahoe floating-point bit pattern.
+ */
+
+int /* 0: OK. */
+flonum_gen2tahoe (format_letter, f, words)
+ char format_letter; /* One of 'd' 'f'. */
+ FLONUM_TYPE *f;
+ LITTLENUM_TYPE *words; /* Deliver answer here. */
+{
+ LITTLENUM_TYPE *lp;
+ int precision;
+ long int exponent_bits;
+ int return_value; /* 0 == OK. */
+
+ return_value = what_kind_of_float (format_letter, &precision, &exponent_bits);
+ if (return_value != 0)
+ {
+ make_invalid_floating_point_number (words);
+ }
+ else
+ {
+ if (f->low > f->leader)
+ {
+ /* 0.0e0 seen. */
+ memset (words, '\0', sizeof (LITTLENUM_TYPE) * precision);
+ }
+ else
+ {
+ long int exponent_1;
+ long int exponent_2;
+ long int exponent_3;
+ long int exponent_4;
+ int exponent_skippage;
+ LITTLENUM_TYPE word1;
+
+ /* JF: Deal with new Nan, +Inf and -Inf codes */
+ if (f->sign != '-' && f->sign != '+')
+ {
+ make_invalid_floating_point_number (words);
+ return return_value;
+ }
+ /*
+ * All tahoe floating_point formats have:
+ * Bit 15 is sign bit.
+ * Bits 14:n are excess-whatever exponent.
+ * Bits n-1:0 (if any) are most significant bits of fraction.
+ * Bits 15:0 of the next word are the next most significant bits.
+ * And so on for each other word.
+ *
+ * So we need: number of bits of exponent, number of bits of
+ * mantissa.
+ */
+
+ bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS;
+ littlenum_pointer = f->leader;
+ littlenum_end = f->low;
+ /* Seek (and forget) 1st significant bit */
+ for (exponent_skippage = 0;
+ !next_bits (1);
+ exponent_skippage++)
+ {
+ }
+ exponent_1 = f->exponent + f->leader + 1 - f->low;
+ /* Radix LITTLENUM_RADIX, point just higher than f -> leader. */
+ exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS;
+ /* Radix 2. */
+ exponent_3 = exponent_2 - exponent_skippage;
+ /* Forget leading zeros, forget 1st bit. */
+ exponent_4 = exponent_3 + (1 << (exponent_bits - 1));
+ /* Offset exponent. */
+
+ if (exponent_4 & ~mask[exponent_bits])
+ {
+ /*
+ * Exponent overflow. Lose immediately.
+ */
+
+ make_invalid_floating_point_number (words);
+
+ /*
+ * We leave return_value alone: admit we read the
+ * number, but return a floating exception
+ * because we can't encode the number.
+ */
+ }
+ else
+ {
+ lp = words;
+
+ /* Word 1. Sign, exponent and perhaps high bits. */
+ /* Assume 2's complement integers. */
+ word1 = ((exponent_4 & mask[exponent_bits]) << (15 - exponent_bits))
+ | ((f->sign == '+') ? 0 : 0x8000)
+ | next_bits (15 - exponent_bits);
+ *lp++ = word1;
+
+ /* The rest of the words are just mantissa bits. */
+ for (; lp < words + precision; lp++)
+ {
+ *lp = next_bits (LITTLENUM_NUMBER_OF_BITS);
+ }
+
+ if (next_bits (1))
+ {
+ /*
+ * Since the NEXT bit is a 1, round UP the mantissa.
+ * The cunning design of these hidden-1 floats permits
+ * us to let the mantissa overflow into the exponent, and
+ * it 'does the right thing'. However, we lose if the
+ * highest-order bit of the lowest-order word flips.
+ * Is that clear?
+ */
+
+ unsigned long int carry;
+
+ /*
+ #if (sizeof(carry)) < ((sizeof(bits[0]) * BITS_PER_CHAR) + 2)
+ Please allow at least 1 more bit in carry than is in a LITTLENUM.
+ We need that extra bit to hold a carry during a LITTLENUM carry
+ propagation. Another extra bit (kept 0) will assure us that we
+ don't get a sticky sign bit after shifting right, and that
+ permits us to propagate the carry without any masking of bits.
+ #endif
+ */
+ for (carry = 1, lp--;
+ carry && (lp >= words);
+ lp--)
+ {
+ carry = *lp + carry;
+ *lp = carry;
+ carry >>= LITTLENUM_NUMBER_OF_BITS;
+ }
+
+ if ((word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1)))
+ {
+ make_invalid_floating_point_number (words);
+ /*
+ * We leave return_value alone: admit we read the
+ * number, but return a floating exception
+ * because we can't encode the number.
+ */
+ }
+ } /* if (we needed to round up) */
+ } /* if (exponent overflow) */
+ } /* if (0.0e0) */
+ } /* if (float_type was OK) */
+ return (return_value);
+}
+\f
+/*
+ * md_atof()
+ *
+ * In: input_line_pointer -> the 1st character of a floating-point
+ * number.
+ * 1 letter denoting the type of statement that wants a
+ * binary floating point number returned.
+ * Address of where to build floating point literal.
+ * Assumed to be 'big enough'.
+ * Address of where to return size of literal (in chars).
+ *
+ * Out: Input_line_pointer -> of next char after floating number.
+ * Error message, or "".
+ * Floating point literal.
+ * Number of chars we used for the literal.
+ */
+
+char *
+md_atof (what_statement_type, literalP, sizeP)
+ char what_statement_type;
+ char *literalP;
+ int *sizeP;
+{
+ LITTLENUM_TYPE words[MAX_PRECISION];
+ register char kind_of_float;
+ register int number_of_chars;
+ register LITTLENUM_TYPE *littlenum_pointer;
+
+ switch (what_statement_type)
+ {
+ case 'f': /* .ffloat */
+ case 'd': /* .dfloat */
+ kind_of_float = what_statement_type;
+ break;
+
+ default:
+ kind_of_float = 0;
+ break;
+ };
+
+ if (kind_of_float)
+ {
+ register LITTLENUM_TYPE *limit;
+
+ input_line_pointer = atof_tahoe (input_line_pointer,
+ kind_of_float,
+ words);
+ /*
+ * The atof_tahoe() builds up 16-bit numbers.
+ * Since the assembler may not be running on
+ * a different-endian machine, be very careful about
+ * converting words to chars.
+ */
+ number_of_chars = (kind_of_float == 'f' ? F_PRECISION_CHARS :
+ (kind_of_float == 'd' ? D_PRECISION_CHARS : 0));
+ know (number_of_chars <= MAX_PRECISION * sizeof (LITTLENUM_TYPE));
+ limit = words + (number_of_chars / sizeof (LITTLENUM_TYPE));
+ for (littlenum_pointer = words;
+ littlenum_pointer < limit;
+ littlenum_pointer++)
+ {
+ md_number_to_chars (literalP, *littlenum_pointer,
+ sizeof (LITTLENUM_TYPE));
+ literalP += sizeof (LITTLENUM_TYPE);
+ };
+ }
+ else
+ {
+ number_of_chars = 0;
+ };
+
+ *sizeP = number_of_chars;
+ return (kind_of_float ? "" : "Bad call to md_atof()");
+} /* md_atof() */
+
+/* atof_tahoe.c */
projects / deliverable / binutils-gdb.git / commitdiff
