75f88ba495
.weak as gcc and g++ would like to use. This includes changes to other architectures mostly for completeness, I don't expect cross-assemblink would work but I could be wrong. Obtained from: NetBSD
438 lines
12 KiB
C
438 lines
12 KiB
C
/* atof_ns32k.c - turn a Flonum into a ns32k floating point number
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Copyright (C) 1987 Free Software Foundation, Inc.
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This file is part of GAS, the GNU Assembler.
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GAS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 1, or (at your option)
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any later version.
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GAS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GAS; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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/* this is atof-m68k.c hacked for ns32k */
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#include "as.h"
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extern FLONUM_TYPE generic_floating_point_number; /* Flonums returned here. */
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extern char EXP_CHARS[];
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/* Precision in LittleNums. */
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#define MAX_PRECISION (4)
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#define F_PRECISION (2)
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#define D_PRECISION (4)
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/* Length in LittleNums of guard bits. */
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#define GUARD (2)
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int /* Number of chars in flonum type 'letter'. */
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atof_sizeof (letter)
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char letter;
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{
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int return_value;
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/*
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* Permitting uppercase letters is probably a bad idea.
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* Please use only lower-cased letters in case the upper-cased
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* ones become unsupported!
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*/
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switch (letter)
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{
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case 'f':
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return_value = F_PRECISION;
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break;
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case 'd':
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return_value = D_PRECISION;
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break;
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default:
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return_value = 0;
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break;
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}
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return (return_value);
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}
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static unsigned long int mask[] = {
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0x00000000,
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0x00000001,
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0x00000003,
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0x00000007,
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0x0000000f,
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0x0000001f,
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0x0000003f,
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0x0000007f,
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0x000000ff,
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0x000001ff,
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0x000003ff,
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0x000007ff,
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0x00000fff,
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0x00001fff,
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0x00003fff,
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0x00007fff,
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0x0000ffff,
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0x0001ffff,
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0x0003ffff,
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0x0007ffff,
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0x000fffff,
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0x001fffff,
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0x003fffff,
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0x007fffff,
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0x00ffffff,
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0x01ffffff,
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0x03ffffff,
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0x07ffffff,
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0x0fffffff,
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0x1fffffff,
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0x3fffffff,
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0x7fffffff,
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0xffffffff
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};
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static int bits_left_in_littlenum;
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static int littlenums_left;
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static LITTLENUM_TYPE * littlenum_pointer;
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static int
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next_bits (number_of_bits)
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int number_of_bits;
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{
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int return_value;
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if (!littlenums_left)
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return 0;
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if (number_of_bits >= bits_left_in_littlenum)
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{
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return_value = mask[bits_left_in_littlenum] & *littlenum_pointer;
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number_of_bits -= bits_left_in_littlenum;
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return_value <<= number_of_bits;
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if (littlenums_left) {
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bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits;
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littlenum_pointer --;
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--littlenums_left;
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return_value |= (*littlenum_pointer>>bits_left_in_littlenum) & mask[number_of_bits];
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}
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}
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else
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{
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bits_left_in_littlenum -= number_of_bits;
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return_value = mask[number_of_bits] & (*littlenum_pointer>>bits_left_in_littlenum);
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}
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return (return_value);
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}
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static void
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make_invalid_floating_point_number (words)
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LITTLENUM_TYPE * words;
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{
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/* Zero the leftmost bit */
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words[0]= (LITTLENUM_TYPE) ((unsigned)-1)>>1;
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words[1]= (LITTLENUM_TYPE) -1;
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words[2]= (LITTLENUM_TYPE) -1;
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words[3]= (LITTLENUM_TYPE) -1;
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}
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/***********************************************************************\
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* *
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* Warning: this returns 16-bit LITTLENUMs, because that is *
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* what the VAX thinks in. It is up to the caller to figure *
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* out any alignment problems and to conspire for the bytes/word *
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* to be emitted in the right order. Bigendians beware! *
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* *
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\***********************************************************************/
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char * /* Return pointer past text consumed. */
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atof_ns32k (str, what_kind, words)
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char * str; /* Text to convert to binary. */
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char what_kind; /* 'd', 'f', 'g', 'h' */
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LITTLENUM_TYPE * words; /* Build the binary here. */
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{
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FLONUM_TYPE f;
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LITTLENUM_TYPE bits[MAX_PRECISION + MAX_PRECISION + GUARD];
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/* Extra bits for zeroed low-order bits. */
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/* The 1st MAX_PRECISION are zeroed, */
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/* the last contain flonum bits. */
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char * return_value;
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int precision; /* Number of 16-bit words in the format. */
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long int exponent_bits;
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long int exponent_1;
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long int exponent_2;
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long int exponent_3;
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long int exponent_4;
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int exponent_skippage;
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LITTLENUM_TYPE word1;
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LITTLENUM_TYPE * lp;
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return_value = str;
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f.low = bits + MAX_PRECISION;
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f.high = NULL;
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f.leader = NULL;
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f.exponent = NULL;
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f.sign = '\0';
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/* Use more LittleNums than seems */
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/* necessary: the highest flonum may have */
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/* 15 leading 0 bits, so could be useless. */
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bzero (bits, sizeof(LITTLENUM_TYPE) * MAX_PRECISION);
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switch (what_kind) {
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case 'f':
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precision = F_PRECISION;
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exponent_bits = 8;
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break;
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case 'd':
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precision = D_PRECISION;
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exponent_bits = 11;
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break;
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default:
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make_invalid_floating_point_number (words);
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return NULL;
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}
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f.high = f.low + precision - 1 + GUARD;
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if (atof_generic (& return_value, ".", EXP_CHARS, & f)) {
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as_warn("Error converting floating point number (Exponent overflow?)");
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make_invalid_floating_point_number (words);
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return NULL;
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}
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if (f.low > f.leader) {
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/* 0.0e0 seen. */
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bzero (words, sizeof(LITTLENUM_TYPE) * precision);
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return return_value;
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}
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if (f.sign != '+' && f.sign != '-') {
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make_invalid_floating_point_number(words);
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return NULL;
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}
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/*
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* All vaxen floating_point formats (so far) have:
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* Bit 15 is sign bit.
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* Bits 14:n are excess-whatever exponent.
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* Bits n-1:0 (if any) are most significant bits of fraction.
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* Bits 15:0 of the next word are the next most significant bits.
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* And so on for each other word.
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*
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* So we need: number of bits of exponent, number of bits of
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* mantissa.
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*/
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bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS;
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littlenum_pointer = f.leader;
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littlenums_left = 1 + f.leader-f.low;
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/* Seek (and forget) 1st significant bit */
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for (exponent_skippage = 0;! next_bits(1); exponent_skippage ++)
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;
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exponent_1 = f.exponent + f.leader + 1 - f.low;
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/* Radix LITTLENUM_RADIX, point just higher than f.leader. */
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exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS;
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/* Radix 2. */
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exponent_3 = exponent_2 - exponent_skippage;
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/* Forget leading zeros, forget 1st bit. */
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exponent_4 = exponent_3 + ((1 << (exponent_bits - 1)) - 2);
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/* Offset exponent. */
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if (exponent_4 & ~ mask[exponent_bits]) {
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/*
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* Exponent overflow. Lose immediately.
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*/
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/*
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* We leave return_value alone: admit we read the
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* number, but return a floating exception
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* because we can't encode the number.
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*/
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as_warn("Exponent overflow in floating-point number");
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make_invalid_floating_point_number (words);
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return return_value;
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}
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lp = words;
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/* Word 1. Sign, exponent and perhaps high bits. */
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/* Assume 2's complement integers. */
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word1 = ((exponent_4 & mask[exponent_bits]) << (15 - exponent_bits)) |
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((f.sign == '+') ? 0 : 0x8000) | next_bits (15 - exponent_bits);
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* lp ++ = word1;
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/* The rest of the words are just mantissa bits. */
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for (; lp < words + precision; lp++)
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* lp = next_bits (LITTLENUM_NUMBER_OF_BITS);
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if (next_bits (1)) {
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unsigned long int carry;
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/*
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* Since the NEXT bit is a 1, round UP the mantissa.
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* The cunning design of these hidden-1 floats permits
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* us to let the mantissa overflow into the exponent, and
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* it 'does the right thing'. However, we lose if the
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* highest-order bit of the lowest-order word flips.
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* Is that clear?
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*/
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/* #if (sizeof(carry)) < ((sizeof(bits[0]) * BITS_PER_CHAR) + 2)
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Please allow at least 1 more bit in carry than is in a LITTLENUM.
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We need that extra bit to hold a carry during a LITTLENUM carry
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propagation. Another extra bit (kept 0) will assure us that we
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don't get a sticky sign bit after shifting right, and that
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permits us to propagate the carry without any masking of bits.
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#endif */
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for (carry = 1, lp --; carry && (lp >= words); lp --) {
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carry = * lp + carry;
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* lp = carry;
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carry >>= LITTLENUM_NUMBER_OF_BITS;
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}
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if ( (word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1)) ) {
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/* We leave return_value alone: admit we read the
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* number, but return a floating exception
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* because we can't encode the number.
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*/
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make_invalid_floating_point_number (words);
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return return_value;
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}
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}
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return (return_value);
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}
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/* This is really identical to atof_ns32k except for some details */
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gen_to_words(words,precision,exponent_bits)
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LITTLENUM_TYPE *words;
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long int exponent_bits;
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{
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int return_value=0;
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long int exponent_1;
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long int exponent_2;
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long int exponent_3;
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long int exponent_4;
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int exponent_skippage;
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LITTLENUM_TYPE word1;
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LITTLENUM_TYPE * lp;
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if (generic_floating_point_number.low > generic_floating_point_number.leader) {
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/* 0.0e0 seen. */
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bzero (words, sizeof(LITTLENUM_TYPE) * precision);
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return return_value;
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}
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/*
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* All vaxen floating_point formats (so far) have:
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* Bit 15 is sign bit.
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* Bits 14:n are excess-whatever exponent.
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* Bits n-1:0 (if any) are most significant bits of fraction.
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* Bits 15:0 of the next word are the next most significant bits.
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* And so on for each other word.
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*
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* So we need: number of bits of exponent, number of bits of
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* mantissa.
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*/
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bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS;
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littlenum_pointer = generic_floating_point_number.leader;
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littlenums_left = 1+generic_floating_point_number.leader - generic_floating_point_number.low;
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/* Seek (and forget) 1st significant bit */
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for (exponent_skippage = 0;! next_bits(1); exponent_skippage ++)
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;
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exponent_1 = generic_floating_point_number.exponent + generic_floating_point_number.leader + 1 -
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generic_floating_point_number.low;
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/* Radix LITTLENUM_RADIX, point just higher than generic_floating_point_number.leader. */
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exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS;
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/* Radix 2. */
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exponent_3 = exponent_2 - exponent_skippage;
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/* Forget leading zeros, forget 1st bit. */
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exponent_4 = exponent_3 + ((1 << (exponent_bits - 1)) - 2);
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/* Offset exponent. */
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if (exponent_4 & ~ mask[exponent_bits]) {
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/*
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* Exponent overflow. Lose immediately.
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*/
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/*
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* We leave return_value alone: admit we read the
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* number, but return a floating exception
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* because we can't encode the number.
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*/
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make_invalid_floating_point_number (words);
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return return_value;
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}
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lp = words;
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/* Word 1. Sign, exponent and perhaps high bits. */
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/* Assume 2's complement integers. */
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word1 = ((exponent_4 & mask[exponent_bits]) << (15 - exponent_bits)) |
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((generic_floating_point_number.sign == '+') ? 0 : 0x8000) | next_bits (15 - exponent_bits);
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* lp ++ = word1;
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/* The rest of the words are just mantissa bits. */
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for (; lp < words + precision; lp++)
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* lp = next_bits (LITTLENUM_NUMBER_OF_BITS);
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if (next_bits (1)) {
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unsigned long int carry;
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/*
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* Since the NEXT bit is a 1, round UP the mantissa.
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* The cunning design of these hidden-1 floats permits
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* us to let the mantissa overflow into the exponent, and
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* it 'does the right thing'. However, we lose if the
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* highest-order bit of the lowest-order word flips.
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* Is that clear?
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*/
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/* #if (sizeof(carry)) < ((sizeof(bits[0]) * BITS_PER_CHAR) + 2)
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Please allow at least 1 more bit in carry than is in a LITTLENUM.
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We need that extra bit to hold a carry during a LITTLENUM carry
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propagation. Another extra bit (kept 0) will assure us that we
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don't get a sticky sign bit after shifting right, and that
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permits us to propagate the carry without any masking of bits.
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#endif */
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for (carry = 1, lp --; carry && (lp >= words); lp --) {
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carry = * lp + carry;
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* lp = carry;
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carry >>= LITTLENUM_NUMBER_OF_BITS;
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}
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if ( (word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1)) ) {
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/* We leave return_value alone: admit we read the
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* number, but return a floating exception
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* because we can't encode the number.
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*/
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make_invalid_floating_point_number (words);
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return return_value;
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}
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}
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return (return_value);
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}
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/* This routine is a real kludge. Someone really should do it better, but
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I'm too lazy, and I don't understand this stuff all too well anyway
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(JF)
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*/
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void int_to_gen(x)
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long x;
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{
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char buf[20];
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char *bufp;
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sprintf(buf,"%ld",x);
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bufp= &buf[0];
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if (atof_generic(&bufp,".", EXP_CHARS, &generic_floating_point_number))
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as_warn("Error converting number to floating point (Exponent overflow?)");
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}
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