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Diffstat (limited to 'gas/config/atof-vax.c')
| -rw-r--r-- | gas/config/atof-vax.c | 517 |
1 files changed, 517 insertions, 0 deletions
diff --git a/gas/config/atof-vax.c b/gas/config/atof-vax.c new file mode 100644 index 00000000000..45b90a8cc24 --- /dev/null +++ b/gas/config/atof-vax.c @@ -0,0 +1,517 @@ +/* atof_vax.c - turn a Flonum into a VAX floating point number + Copyright (C) 1987, 1992, 93, 95, 1997, 1998 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, 59 Temple Place - Suite 330, Boston, MA + 02111-1307, USA. */ + +#include "as.h" + +static int atof_vax_sizeof PARAMS ((int)); +static int next_bits PARAMS ((int)); +static void make_invalid_floating_point_number PARAMS ((LITTLENUM_TYPE *)); +static int what_kind_of_float PARAMS ((int, int *, long *)); +static char *atof_vax PARAMS ((char *, int, LITTLENUM_TYPE *)); + +/* 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) + +int flonum_gen2vax PARAMS ((int format_letter, FLONUM_TYPE * f, + LITTLENUM_TYPE * words)); + +/* Number of chars in flonum type 'letter'. */ +static int +atof_vax_sizeof (letter) + int 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 < littlenum_end) + 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; + 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) + int 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! * + * * + \***********************************************************************/ + +static char * /* Return pointer past text consumed. */ +atof_vax (str, what_kind, words) + char *str; /* Text to convert to binary. */ + int 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 = 0; + 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 0. + * 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) + int 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 *littlenumP; + + 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 (littlenumP = words; littlenumP < limit; littlenumP++) + { + md_number_to_chars (literalP, *littlenumP, sizeof (LITTLENUM_TYPE)); + literalP += sizeof (LITTLENUM_TYPE); + }; + } + else + { + number_of_chars = 0; + }; + + *sizeP = number_of_chars; + return kind_of_float ? 0 : _("Bad call to md_atof()"); +} + +/* end of atof-vax.c */ |