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/* atof_ns32k.c - turn a Flonum into a ns32k floating point number
Copyright (C) 1987 Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
GAS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.
GAS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GAS; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
/* this is atof-m68k.c hacked for ns32k */
#include "as.h"
extern FLONUM_TYPE generic_floating_point_number; /* Flonums returned here. */
extern const char EXP_CHARS[];
/* Precision in LittleNums. */
#define MAX_PRECISION (4)
#define F_PRECISION (2)
#define D_PRECISION (4)
/* Length in LittleNums of guard bits. */
#define GUARD (2)
int /* Number of chars in flonum type 'letter'. */
atof_sizeof (letter)
char letter;
{
int return_value;
/*
* Permitting uppercase letters is probably a bad idea.
* Please use only lower-cased letters in case the upper-cased
* ones become unsupported!
*/
switch (letter)
{
case 'f':
return_value = F_PRECISION;
break;
case 'd':
return_value = D_PRECISION;
break;
default:
return_value = 0;
break;
}
return (return_value);
}
static unsigned 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
};
static int bits_left_in_littlenum;
static int littlenums_left;
static LITTLENUM_TYPE *littlenum_pointer;
static int
next_bits (number_of_bits)
int number_of_bits;
{
int return_value;
if (!littlenums_left)
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;
if (littlenums_left)
{
bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits;
littlenum_pointer--;
--littlenums_left;
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[0] = ((unsigned) -1) >> 1; /* Zero the leftmost bit */
words[1] = -1;
words[2] = -1;
words[3] = -1;
}
/***********************************************************************\
* *
* 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_ns32k (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;
long int exponent_1;
long int exponent_2;
long int exponent_3;
long int exponent_4;
int exponent_skippage;
LITTLENUM_TYPE word1;
LITTLENUM_TYPE *lp;
return_value = str;
f.low = bits + MAX_PRECISION;
f.high = NULL;
f.leader = NULL;
f.exponent = NULL;
f.sign = '\0';
/* Use more LittleNums than seems */
/* necessary: the highest flonum may have */
/* 15 leading 0 bits, so could be useless. */
bzero (bits, sizeof (LITTLENUM_TYPE) * MAX_PRECISION);
switch (what_kind)
{
case 'f':
precision = F_PRECISION;
exponent_bits = 8;
break;
case 'd':
precision = D_PRECISION;
exponent_bits = 11;
break;
default:
make_invalid_floating_point_number (words);
return NULL;
}
f.high = f.low + precision - 1 + GUARD;
if (atof_generic (&return_value, ".", EXP_CHARS, &f))
{
as_warn ("Error converting floating point number (Exponent overflow?)");
make_invalid_floating_point_number (words);
return NULL;
}
if (f.low > f.leader)
{
/* 0.0e0 seen. */
bzero (words, sizeof (LITTLENUM_TYPE) * precision);
return return_value;
}
if (f.sign != '+' && f.sign != '-')
{
make_invalid_floating_point_number (words);
return NULL;
}
/*
* All vaxen floating_point formats (so far) 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;
littlenums_left = 1 + f.leader - 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)) - 2);
/* Offset exponent. */
if (exponent_4 & ~mask[exponent_bits])
{
/*
* Exponent overflow. Lose immediately.
*/
/*
* We leave return_value alone: admit we read the
* number, but return a floating exception
* because we can't encode the number.
*/
as_warn ("Exponent overflow in floating-point number");
make_invalid_floating_point_number (words);
return return_value;
}
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))
{
unsigned long int carry;
/*
* 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?
*/
/* #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)))
{
/* We leave return_value alone: admit we read the
* number, but return a floating exception
* because we can't encode the number.
*/
make_invalid_floating_point_number (words);
return return_value;
}
}
return (return_value);
}
/* This is really identical to atof_ns32k except for some details */
gen_to_words (words, precision, exponent_bits)
LITTLENUM_TYPE *words;
long int exponent_bits;
{
int return_value = 0;
long int exponent_1;
long int exponent_2;
long int exponent_3;
long int exponent_4;
int exponent_skippage;
LITTLENUM_TYPE word1;
LITTLENUM_TYPE *lp;
if (generic_floating_point_number.low > generic_floating_point_number.leader)
{
/* 0.0e0 seen. */
bzero (words, sizeof (LITTLENUM_TYPE) * precision);
return return_value;
}
/*
* All vaxen floating_point formats (so far) 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 = generic_floating_point_number.leader;
littlenums_left = 1 + generic_floating_point_number.leader - generic_floating_point_number.low;
/* Seek (and forget) 1st significant bit */
for (exponent_skippage = 0; !next_bits (1); exponent_skippage++)
;
exponent_1 = generic_floating_point_number.exponent + generic_floating_point_number.leader + 1 -
generic_floating_point_number.low;
/* Radix LITTLENUM_RADIX, point just higher than generic_floating_point_number.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)) - 2);
/* Offset exponent. */
if (exponent_4 & ~mask[exponent_bits])
{
/*
* Exponent overflow. Lose immediately.
*/
/*
* We leave return_value alone: admit we read the
* number, but return a floating exception
* because we can't encode the number.
*/
make_invalid_floating_point_number (words);
return return_value;
}
lp = words;
/* Word 1. Sign, exponent and perhaps high bits. */
/* Assume 2's complement integers. */
word1 = ((exponent_4 & mask[exponent_bits]) << (15 - exponent_bits)) |
((generic_floating_point_number.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))
{
unsigned long int carry;
/*
* 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?
*/
/* #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)))
{
/* We leave return_value alone: admit we read the
* number, but return a floating exception
* because we can't encode the number.
*/
make_invalid_floating_point_number (words);
return return_value;
}
}
return (return_value);
}
/* This routine is a real kludge. Someone really should do it better, but
I'm too lazy, and I don't understand this stuff all too well anyway
(JF)
*/
void
int_to_gen (x)
long x;
{
char buf[20];
char *bufp;
sprintf (buf, "%ld", x);
bufp = &buf[0];
if (atof_generic (&bufp, ".", EXP_CHARS, &generic_floating_point_number))
as_warn ("Error converting number to floating point (Exponent overflow?)");
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.