/* atof_vax.c - turn a Flonum into a VAX floating point number Copyright (C) 1987, 1992 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 2, 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. */ /* JF added these two for md_atof() */ #include "as.h" /* Precision in LittleNums. */ #define MAX_PRECISION (8) #define H_PRECISION (8) #define G_PRECISION (4) #define D_PRECISION (4) #define F_PRECISION (2) /* Length in LittleNums of guard bits. */ #define GUARD (2) #if __STDC__ == 1 int flonum_gen2vax(int format_letter, FLONUM_TYPE *f, LITTLENUM_TYPE *words); #else /* not __STDC__ */ int flonum_gen2vax(); #endif /* not __STDC__ */ int /* Number of chars in flonum type 'letter'. */ atof_vax_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': case 'F': return_value = 4; break; case 'd': case 'D': case 'g': case 'G': return_value = 8; break; case 'h': case 'H': return_value = 16; break; default: return_value = 0; break; } return (return_value); } /* atof_vax_sizeof */ static const long 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 }; /* Shared between flonum_gen2vax and next_bits */ static int bits_left_in_littlenum; static LITTLENUM_TYPE * littlenum_pointer; static LITTLENUM_TYPE * littlenum_end; static int next_bits (number_of_bits) int number_of_bits; { int return_value; if (littlenum_pointer= 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; bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits; littlenum_pointer --; if (littlenum_pointer >= littlenum_end) 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 = 0x8000; /* Floating Reserved Operand Code */ } static int /* 0 means letter is OK. */ what_kind_of_float (letter, precisionP, exponent_bitsP) char letter; /* In: lowercase please. What kind of float? */ int * precisionP; /* Number of 16-bit words in the float. */ long * exponent_bitsP; /* Number of exponent bits. */ { int retval; /* 0: OK. */ retval = 0; switch (letter) { case 'f': * precisionP = F_PRECISION; * exponent_bitsP = 8; break; case 'd': * precisionP = D_PRECISION; * exponent_bitsP = 8; break; case 'g': * precisionP = G_PRECISION; * exponent_bitsP = 11; break; case 'h': * precisionP = H_PRECISION; * exponent_bitsP = 15; break; default: retval = 69; break; } return (retval); } /***********************************************************************\ * * * 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_vax(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 exponent_bits; return_value = str; f.low = bits + MAX_PRECISION; f.high = NULL; f.leader = NULL; f.exponent = NULL; f.sign = '\0'; if (what_kind_of_float (what_kind, & precision, & exponent_bits)) { return_value = NULL; /* We lost. */ make_invalid_floating_point_number (words); } if (return_value) { memset(bits, '\0', sizeof(LITTLENUM_TYPE) * MAX_PRECISION); /* Use more LittleNums than seems */ /* necessary: the highest flonum may have */ /* 15 leading 0 bits, so could be useless. */ f.high = f.low + precision - 1 + GUARD; if (atof_generic (& return_value, ".", "eE", & f)) { make_invalid_floating_point_number (words); return_value = NULL; /* we lost */ } else { if (flonum_gen2vax(what_kind, & f, words)) { return_value = NULL; } } } return(return_value); } /* atof_vax() */ /* * In: a flonum, a vax floating point format. * Out: a vax floating-point bit pattern. */ int /* 0: OK. */ flonum_gen2vax (format_letter, f, words) char format_letter; /* One of 'd' 'f' 'g' 'h'. */ FLONUM_TYPE *f; LITTLENUM_TYPE *words; /* Deliver answer here. */ { LITTLENUM_TYPE *lp; int precision; long exponent_bits; int return_value; /* 0 == OK. */ return_value = what_kind_of_float(format_letter, &precision, &exponent_bits); if (return_value != 0) { make_invalid_floating_point_number (words); } else { if (f->low > f->leader) { /* 0.0e0 seen. */ memset(words, '\0', sizeof(LITTLENUM_TYPE) * precision); } else { long exponent_1; long exponent_2; long exponent_3; long exponent_4; int exponent_skippage; LITTLENUM_TYPE word1; /* JF: Deal with new Nan, +Inf and -Inf codes */ if (f->sign != '-' && f->sign != '+') { make_invalid_floating_point_number(words); 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. * * All this to be compatible with a KF11?? (Which is still faster * than lots of vaxen I can think of, but it also has higher * maintenance costs ... sigh). * * So we need: number of bits of exponent, number of bits of * mantissa. */ #ifdef NEVER /******* This zeroing seems redundant - Dean 3may86 **********/ /* * No matter how few bits we got back from the atof() * routine, add enough zero littlenums so the rest of the * code won't run out of "significant" bits in the mantissa. */ { LITTLENUM_TYPE *ltp; for (ltp = f->leader + 1; ltp <= f->low + precision; ltp++) { *ltp = 0; } } #endif bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS; littlenum_pointer = f->leader; littlenum_end = 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)); /* Offset exponent. */ if (exponent_4 & ~mask[exponent_bits]) { /* * Exponent overflow. Lose immediately. */ make_invalid_floating_point_number (words); /* * We leave return_value alone: admit we read the * number, but return a floating exception * because we can't encode the number. */ } else { 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)) { /* * 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? */ unsigned long carry; /* #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))) { make_invalid_floating_point_number(words); /* * We leave return_value alone: admit we read the * number, but return a floating exception * because we can't encode the number. */ } } /* if (we needed to round up) */ } /* if (exponent overflow) */ } /* if (0.0e0) */ } /* if (float_type was OK) */ return(return_value); } /* flonum_gen2vax() */ /* JF this used to be in vax.c but this looks like a better place for it */ /* * md_atof() * * In: input_line_pointer->the 1st character of a floating-point * number. * 1 letter denoting the type of statement that wants a * binary floating point number returned. * Address of where to build floating point literal. * Assumed to be 'big enough'. * Address of where to return size of literal (in chars). * * Out: Input_line_pointer->of next char after floating number. * Error message, or "". * Floating point literal. * Number of chars we used for the literal. */ #define MAXIMUM_NUMBER_OF_LITTLENUMS (8) /* For .hfloats. */ char * md_atof (what_statement_type, literalP, sizeP) char what_statement_type; char * literalP; int * sizeP; { LITTLENUM_TYPE words[MAXIMUM_NUMBER_OF_LITTLENUMS]; register char kind_of_float; register int number_of_chars; register LITTLENUM_TYPE * littlenum_pointer; switch (what_statement_type) { case 'F': /* .float */ case 'f': /* .ffloat */ kind_of_float = 'f'; break; case 'D': /* .double */ case 'd': /* .dfloat */ kind_of_float = 'd'; break; case 'g': /* .gfloat */ kind_of_float = 'g'; break; case 'h': /* .hfloat */ kind_of_float = 'h'; break; default: kind_of_float = 0; break; }; if (kind_of_float) { register LITTLENUM_TYPE * limit; input_line_pointer = atof_vax (input_line_pointer, kind_of_float, words); /* * The atof_vax() builds up 16-bit numbers. * Since the assembler may not be running on * a little-endian machine, be very careful about * converting words to chars. */ number_of_chars = atof_vax_sizeof (kind_of_float); know( number_of_chars <= MAXIMUM_NUMBER_OF_LITTLENUMS * sizeof(LITTLENUM_TYPE) ); limit = words + (number_of_chars / sizeof(LITTLENUM_TYPE)); for (littlenum_pointer = words; littlenum_pointer < limit; littlenum_pointer ++) { md_number_to_chars (literalP, * littlenum_pointer, sizeof(LITTLENUM_TYPE)); literalP += sizeof(LITTLENUM_TYPE); }; } else { number_of_chars = 0; }; * sizeP = number_of_chars; return (kind_of_float ? "" : "Bad call to md_atof()"); } /* md_atof() */ /* end of atof-vax.c */