+/* atof_ieee.c - turn a Flonum into an IEEE 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. */
+
+#include "flonum.h"
+#ifdef USG
+#define bzero(s,n) memset(s,0,n)
+#define bcopy(from,to,n) memcpy((to),(from),(n))
+#endif
+
+extern FLONUM_TYPE generic_floating_point_number; /* Flonums returned here. */
+#define NULL (0)
+
+extern char EXP_CHARS[];
+ /* Precision in LittleNums. */
+#define MAX_PRECISION (6)
+#define F_PRECISION (2)
+#define D_PRECISION (4)
+#define X_PRECISION (6)
+#define P_PRECISION (6)
+
+ /* Length in LittleNums of guard bits. */
+#define GUARD (2)
+
+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
+ };
+\f
+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 --;
+ 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);
+}
+
+/* Num had better be less than LITTLENUM_NUMBER_OF_BITS */
+static int
+unget_bits(num)
+{
+ if(!littlenums_left) {
+ ++littlenum_pointer;
+ ++littlenums_left;
+ bits_left_in_littlenum=num;
+ } else if(bits_left_in_littlenum+num>LITTLENUM_NUMBER_OF_BITS) {
+ bits_left_in_littlenum= num-(LITTLENUM_NUMBER_OF_BITS-bits_left_in_littlenum);
+ ++littlenum_pointer;
+ ++littlenums_left;
+ } else
+ bits_left_in_littlenum+=num;
+}
+
+static void
+make_invalid_floating_point_number (words)
+ LITTLENUM_TYPE * words;
+{
+ as_warn("cannot create floating-point number");
+ words[0]= ((unsigned)-1)>>1; /* Zero the leftmost bit */
+ words[1]= -1;
+ words[2]= -1;
+ words[3]= -1;
+ words[4]= -1;
+ words[5]= -1;
+}
+\f
+/***********************************************************************\
+* Warning: this returns 16-bit LITTLENUMs. 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! *
+* *
+\***********************************************************************/
+
+/* Note that atof-ieee always has X and P precisions enabled. it is up
+ to md_atof to filter them out if the target machine does not support
+ them. */
+
+char * /* Return pointer past text consumed. */
+atof_ieee (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. */
+{
+ static 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;
+ generic_floating_point_number.low = bits + MAX_PRECISION;
+ generic_floating_point_number.high = NULL;
+ generic_floating_point_number.leader = NULL;
+ generic_floating_point_number.exponent = NULL;
+ generic_floating_point_number.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':
+ case 'F':
+ case 's':
+ case 'S':
+ precision = F_PRECISION;
+ exponent_bits = 8;
+ break;
+
+ case 'd':
+ case 'D':
+ case 'r':
+ case 'R':
+ precision = D_PRECISION;
+ exponent_bits = 11;
+ break;
+
+ case 'x':
+ case 'X':
+ case 'e':
+ case 'E':
+ precision = X_PRECISION;
+ exponent_bits = 15;
+ break;
+
+ case 'p':
+ case 'P':
+
+ precision = P_PRECISION;
+ exponent_bits= -1;
+ break;
+
+ default:
+ make_invalid_floating_point_number (words);
+ return NULL;
+ }
+
+ generic_floating_point_number.high = generic_floating_point_number.low + precision - 1 + GUARD;
+
+ if (atof_generic (& return_value, ".", EXP_CHARS, & generic_floating_point_number)) {
+ /* as_warn("Error converting floating point number (Exponent overflow?)"); */
+ make_invalid_floating_point_number (words);
+ return NULL;
+ }
+ gen_to_words(words, precision, exponent_bits);
+ return return_value;
+}
+
+/* Turn generic_floating_point_number into a real float/double/extended */
+gen_to_words(words,precision,exponent_bits)
+LITTLENUM_TYPE *words;
+long int exponent_bits;
+int precision;
+{
+ 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. */
+ if(generic_floating_point_number.sign=='+')
+ words[0]=0x0000;
+ else
+ words[0]=0x8000;
+ bzero (&words[1], sizeof(LITTLENUM_TYPE) * (precision-1));
+ return return_value;
+ }
+
+ /* NaN: Do the right thing */
+ if(generic_floating_point_number.sign==0) {
+ if(precision==F_PRECISION) {
+ words[0]=0x7fff;
+ words[1]=0xffff;
+ } else {
+ words[0]=0x7fff;
+ words[1]=0xffff;
+ words[2]=0xffff;
+ words[3]=0xffff;
+ }
+ return return_value;
+ } else if(generic_floating_point_number.sign=='P') {
+ /* +INF: Do the right thing */
+ if(precision==F_PRECISION) {
+ words[0]=0x7f80;
+ words[1]=0;
+ } else {
+ words[0]=0x7ff0;
+ words[1]=0;
+ words[2]=0;
+ words[3]=0;
+ }
+ return return_value;
+ } else if(generic_floating_point_number.sign=='N') {
+ /* Negative INF */
+ if(precision==F_PRECISION) {
+ words[0]=0xff80;
+ words[1]=0x0;
+ } else {
+ words[0]=0xfff0;
+ words[1]=0x0;
+ words[2]=0x0;
+ words[3]=0x0;
+ }
+ return return_value;
+ }
+ /*
+ * The floating point formats we support 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(s) are the next most significant bits.
+ *
+ * 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. */
+
+ lp = words;
+
+ /* Word 1. Sign, exponent and perhaps high bits. */
+ word1 = (generic_floating_point_number.sign == '+') ? 0 : (1<<(LITTLENUM_NUMBER_OF_BITS-1));
+
+ /* Assume 2's complement integers. */
+ if(exponent_4<1 && exponent_4>=-62) {
+ int prec_bits;
+ int num_bits;
+
+ unget_bits(1);
+ num_bits= -exponent_4;
+ prec_bits=LITTLENUM_NUMBER_OF_BITS*precision-(exponent_bits+1+num_bits);
+ if(precision==X_PRECISION && exponent_bits==15)
+ prec_bits-=LITTLENUM_NUMBER_OF_BITS+1;
+
+ if(num_bits>=LITTLENUM_NUMBER_OF_BITS-exponent_bits) {
+ /* Bigger than one littlenum */
+ num_bits-=(LITTLENUM_NUMBER_OF_BITS-1)-exponent_bits;
+ *lp++=word1;
+ if(num_bits+exponent_bits+1>=precision*LITTLENUM_NUMBER_OF_BITS) {
+ /* Exponent overflow */
+ make_invalid_floating_point_number(words);
+ return return_value;
+ }
+ if(precision==X_PRECISION && exponent_bits==15) {
+ *lp++=0;
+ *lp++=0;
+ num_bits-=LITTLENUM_NUMBER_OF_BITS-1;
+ }
+ while(num_bits>=LITTLENUM_NUMBER_OF_BITS) {
+ num_bits-=LITTLENUM_NUMBER_OF_BITS;
+ *lp++=0;
+ }
+ if(num_bits)
+ *lp++=next_bits(LITTLENUM_NUMBER_OF_BITS-(num_bits));
+ } else {
+ if(precision==X_PRECISION && exponent_bits==15) {
+ *lp++=word1;
+ *lp++=0;
+ if(num_bits==LITTLENUM_NUMBER_OF_BITS) {
+ *lp++=0;
+ *lp++=next_bits(LITTLENUM_NUMBER_OF_BITS-1);
+ } else if(num_bits==LITTLENUM_NUMBER_OF_BITS-1)
+ *lp++=0;
+ else
+ *lp++=next_bits(LITTLENUM_NUMBER_OF_BITS-1-num_bits);
+ num_bits=0;
+ } else {
+ word1|= next_bits ((LITTLENUM_NUMBER_OF_BITS-1) - (exponent_bits+num_bits));
+ *lp++=word1;
+ }
+ }
+ while(lp<words+precision)
+ *lp++=next_bits(LITTLENUM_NUMBER_OF_BITS);
+
+ /* Round the mantissa up, but don't change the number */
+ if(next_bits(1)) {
+ --lp;
+ if(prec_bits>LITTLENUM_NUMBER_OF_BITS) {
+ int n = 0;
+ int tmp_bits;
+
+ n=0;
+ tmp_bits=prec_bits;
+ while(tmp_bits>LITTLENUM_NUMBER_OF_BITS) {
+ if(lp[n]!=(LITTLENUM_TYPE)-1)
+ break;
+ --n;
+ tmp_bits-=LITTLENUM_NUMBER_OF_BITS;
+ }
+ if(tmp_bits>LITTLENUM_NUMBER_OF_BITS || (lp[n]&mask[tmp_bits])!=mask[tmp_bits]) {
+ unsigned long int carry;
+
+ for (carry = 1; carry && (lp >= words); lp --) {
+ carry = * lp + carry;
+ * lp = carry;
+ carry >>= LITTLENUM_NUMBER_OF_BITS;
+ }
+ }
+ } else if((*lp&mask[prec_bits])!=mask[prec_bits])
+ lp++;
+ }
+
+ return return_value;
+ } else 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;
+ } else {
+ word1 |= (exponent_4 << ((LITTLENUM_NUMBER_OF_BITS-1) - exponent_bits))
+ | next_bits ((LITTLENUM_NUMBER_OF_BITS-1) - exponent_bits);
+ }
+
+ * lp ++ = word1;
+
+ /* X_PRECISION is special: it has 16 bits of zero in the middle,
+ followed by a 1 bit. */
+ if(exponent_bits==15 && precision==X_PRECISION) {
+ *lp++=0;
+ *lp++= 1<<(LITTLENUM_NUMBER_OF_BITS)|next_bits(LITTLENUM_NUMBER_OF_BITS-1);
+ }
+
+ /* The rest of the words are just mantissa bits. */
+ while(lp < words + precision)
+ *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.
+ */
+ *words&= ~ (1 << (LITTLENUM_NUMBER_OF_BITS - 1));
+ /* 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?)");
+}
+
+#ifdef TEST
+char *
+print_gen(gen)
+FLONUM_TYPE *gen;
+{
+ FLONUM_TYPE f;
+ LITTLENUM_TYPE arr[10];
+ double dv;
+ float fv;
+ static char sbuf[40];
+
+ if(gen) {
+ f=generic_floating_point_number;
+ generic_floating_point_number= *gen;
+ }
+ gen_to_words(&arr[0],4,11);
+ bcopy(&arr[0],&dv,sizeof(double));
+ sprintf(sbuf,"%x %x %x %x %.14G ",arr[0],arr[1],arr[2],arr[3],dv);
+ gen_to_words(&arr[0],2,8);
+ bcopy(&arr[0],&fv,sizeof(float));
+ sprintf(sbuf+strlen(sbuf),"%x %x %.12g\n",arr[0],arr[1],fv);
+ if(gen)
+ generic_floating_point_number=f;
+ return sbuf;
+}
+#endif
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