436 lines
12 KiB
C
436 lines
12 KiB
C
/* 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 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?)");
|
||
}
|