-
/* atof_tahoe.c - turn a string into a Tahoe floating point number
- Copyright (C) 1987, 1998 Free Software Foundation, Inc.
- */
+ Copyright 1987, 1993, 2000 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)
+ my honesty refreshing? Devon E Bowen <bowen@cs.buffalo.edu>
- I don't allow uppercase letters in the precision descrpitors. Ie 'f' and
- 'd' are allowed but 'F' and 'D' aren't */
+ I don't allow uppercase letters in the precision descrpitors.
+ i.e. 'f' and 'd' are allowed but 'F' and 'D' aren't. */
#include "as.h"
-/* Precision in LittleNums. */
+/* Precision in LittleNums. */
#define MAX_PRECISION (4)
#define D_PRECISION (4)
#define F_PRECISION (2)
-/* Precision in chars. */
+/* Precision in chars. */
#define D_PRECISION_CHARS (8)
#define F_PRECISION_CHARS (4)
-/* Length in LittleNums of guard bits. */
+/* Length in LittleNums of guard bits. */
#define GUARD (2)
static const long int mask[] =
0xffffffff
};
\f
-
-/* Shared between flonum_gen2tahoe and next_bits */
+/* 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);
+int flonum_gen2tahoe (int format_letter, FLONUM_TYPE * f,
+ LITTLENUM_TYPE * words);
-#else /* not __STDC__ */
+#else /* not __STDC__ */
int flonum_gen2tahoe ();
-#endif /* not __STDC__ */
-
+#endif /* not __STDC__ */
static int
next_bits (number_of_bits)
return_value = mask[number_of_bits] &
((*littlenum_pointer) >> bits_left_in_littlenum);
}
- return (return_value);
+ return return_value;
}
static void
make_invalid_floating_point_number (words)
LITTLENUM_TYPE *words;
{
- *words = 0x8000; /* Floating Reserved Operand Code */
+ /* Floating Reserved Operand Code. */
+ *words = 0x8000;
}
\f
-static int /* 0 means letter is OK. */
+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. */
+ /* In: lowercase please. What kind of float? */
+ char letter;
+
+ /* Number of 16-bit words in the float. */
+ int *precisionP;
+
+ /* Number of exponent bits. */
+ long int *exponent_bitsP;
{
- int retval; /* 0: OK. */
+ int retval; /* 0: OK. */
retval = 0;
switch (letter)
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. */
+/* 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 *str; /* Text to convert to binary. */
char what_kind; /* 'd', 'f', 'g', 'h' */
- LITTLENUM_TYPE *words; /* Build the binary here. */
+ 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. */
+ /* 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. */
+ int precision; /* Number of 16-bit words in the format. */
long int exponent_bits;
return_value = str;
if (what_kind_of_float (what_kind, &precision, &exponent_bits))
{
- return_value = NULL; /* We lost. */
+ /* We lost. */
+ return_value = NULL;
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. */
+ /* 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 */
+ /* We lost. */
+ return_value = NULL;
}
else
{
if (flonum_gen2tahoe (what_kind, &f, words))
- {
- return_value = NULL;
- }
+ return_value = NULL;
}
}
- return (return_value);
+ return return_value;
}
\f
-/*
- * In: a flonum, a Tahoe floating point format.
- * Out: a Tahoe floating-point bit pattern.
- */
+/* In: a flonum, a Tahoe floating point format.
+ Out: a Tahoe floating-point bit pattern. */
-int /* 0: OK. */
+int /* 0: OK. */
flonum_gen2tahoe (format_letter, f, words)
- char format_letter; /* One of 'd' 'f'. */
+ char format_letter; /* One of 'd' 'f'. */
FLONUM_TYPE *f;
- LITTLENUM_TYPE *words; /* Deliver answer here. */
+ LITTLENUM_TYPE *words; /* Deliver answer here. */
{
LITTLENUM_TYPE *lp;
int precision;
long int exponent_bits;
- int return_value; /* 0 == OK. */
+ int return_value; /* 0 == OK. */
- return_value = what_kind_of_float (format_letter, &precision, &exponent_bits);
+ return_value =
+ what_kind_of_float (format_letter, &precision, &exponent_bits);
if (return_value != 0)
{
make_invalid_floating_point_number (words);
{
if (f->low > f->leader)
{
- /* 0.0e0 seen. */
+ /* 0.0e0 seen. */
memset (words, '\0', sizeof (LITTLENUM_TYPE) * precision);
}
else
int exponent_skippage;
LITTLENUM_TYPE word1;
- /* JF: Deal with new Nan, +Inf and -Inf codes */
+ /* 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.
- */
+ /* 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 */
+
+ /* 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. */
+
+ /* Radix LITTLENUM_RADIX, point just higher than f -> leader. */
exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS;
- /* Radix 2. */
+
+ /* Radix 2. */
exponent_3 = exponent_2 - exponent_skippage;
- /* Forget leading zeros, forget 1st bit. */
+
+ /* Forget leading zeros, forget 1st bit. */
exponent_4 = exponent_3 + (1 << (exponent_bits - 1));
- /* Offset exponent. */
+
+ /* Offset exponent. */
if (exponent_4 & ~mask[exponent_bits])
{
- /*
- * Exponent overflow. Lose immediately.
- */
+ /* 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.
- */
+ /* 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))
+ /* 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. */
+ /* The rest of the words are just mantissa bits. */
for (; lp < words + precision; lp++)
- {
- *lp = next_bits (LITTLENUM_NUMBER_OF_BITS);
- }
+ *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?
- */
+ /* 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
- */
+ /* #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 >>= LITTLENUM_NUMBER_OF_BITS;
}
- if ((word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1)))
+ 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.
- */
+ /* 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);
+ } /* 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
+/* 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.
* Out: Input_line_pointer -> of next char after floating number.
* Error message, or 0.
* Floating point literal.
- * Number of chars we used for the literal.
- */
+ * Number of chars we used for the literal. */
char *
md_atof (what_statement_type, literalP, sizeP)
switch (what_statement_type)
{
- case 'f': /* .ffloat */
- case 'd': /* .dfloat */
+ case 'f': /* .ffloat */
+ case 'd': /* .dfloat */
kind_of_float = what_statement_type;
break;
default:
kind_of_float = 0;
break;
- };
+ }
if (kind_of_float)
{
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.
- */
+ /* 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));
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 ? 0 : _("Bad call to md_atof()");
}
-
-/* atof_tahoe.c */
projects / deliverable / binutils-gdb.git / blobdiff