/* 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?)"); }