761 lines
24 KiB
C
761 lines
24 KiB
C
/*
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* Floating point number functions.
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*
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* Copyright (C) 2001-2007 Peter Johnson
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*
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* Based on public-domain x86 assembly code by Randall Hyde (8/28/91).
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND OTHER CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR OTHER CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "util.h"
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#include <ctype.h>
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#include "coretype.h"
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#include "bitvect.h"
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#include "file.h"
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#include "errwarn.h"
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#include "floatnum.h"
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/* 97-bit internal floating point format:
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* 0000000s eeeeeeee eeeeeeee m.....................................m
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* Sign exponent mantissa (80 bits)
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* 79 0
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*
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* Only L.O. bit of Sign byte is significant. The rest is zero.
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* Exponent is bias 32767.
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* Mantissa does NOT have an implied one bit (it's explicit).
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*/
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struct yasm_floatnum {
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/*@only@*/ wordptr mantissa; /* Allocated to MANT_BITS bits */
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unsigned short exponent;
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unsigned char sign;
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unsigned char flags;
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};
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/* constants describing parameters of internal floating point format */
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#define MANT_BITS 80
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#define MANT_BYTES 10
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#define MANT_SIGDIGITS 24
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#define EXP_BIAS 0x7FFF
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#define EXP_INF 0xFFFF
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#define EXP_MAX 0xFFFE
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#define EXP_MIN 1
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#define EXP_ZERO 0
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/* Flag settings for flags field */
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#define FLAG_ISZERO 1<<0
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/* Note this structure integrates the floatnum structure */
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typedef struct POT_Entry_s {
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yasm_floatnum f;
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int dec_exponent;
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} POT_Entry;
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/* "Source" for POT_Entry. */
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typedef struct POT_Entry_Source_s {
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unsigned char mantissa[MANT_BYTES]; /* little endian mantissa */
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unsigned short exponent; /* Bias 32767 exponent */
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} POT_Entry_Source;
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/* Power of ten tables used by the floating point I/O routines.
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* The POT_Table? arrays are built from the POT_Table?_Source arrays at
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* runtime by POT_Table_Init().
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*/
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/* This table contains the powers of ten raised to negative powers of two:
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*
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* entry[12-n] = 10 ** (-2 ** n) for 0 <= n <= 12.
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* entry[13] = 1.0
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*/
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static /*@only@*/ POT_Entry *POT_TableN;
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static POT_Entry_Source POT_TableN_Source[] = {
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{{0xe3,0x2d,0xde,0x9f,0xce,0xd2,0xc8,0x04,0xdd,0xa6},0x4ad8}, /* 1e-4096 */
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{{0x25,0x49,0xe4,0x2d,0x36,0x34,0x4f,0x53,0xae,0xce},0x656b}, /* 1e-2048 */
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{{0xa6,0x87,0xbd,0xc0,0x57,0xda,0xa5,0x82,0xa6,0xa2},0x72b5}, /* 1e-1024 */
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{{0x33,0x71,0x1c,0xd2,0x23,0xdb,0x32,0xee,0x49,0x90},0x795a}, /* 1e-512 */
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{{0x91,0xfa,0x39,0x19,0x7a,0x63,0x25,0x43,0x31,0xc0},0x7cac}, /* 1e-256 */
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{{0x7d,0xac,0xa0,0xe4,0xbc,0x64,0x7c,0x46,0xd0,0xdd},0x7e55}, /* 1e-128 */
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{{0x24,0x3f,0xa5,0xe9,0x39,0xa5,0x27,0xea,0x7f,0xa8},0x7f2a}, /* 1e-64 */
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{{0xde,0x67,0xba,0x94,0x39,0x45,0xad,0x1e,0xb1,0xcf},0x7f94}, /* 1e-32 */
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{{0x2f,0x4c,0x5b,0xe1,0x4d,0xc4,0xbe,0x94,0x95,0xe6},0x7fc9}, /* 1e-16 */
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{{0xc2,0xfd,0xfc,0xce,0x61,0x84,0x11,0x77,0xcc,0xab},0x7fe4}, /* 1e-8 */
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{{0xc3,0xd3,0x2b,0x65,0x19,0xe2,0x58,0x17,0xb7,0xd1},0x7ff1}, /* 1e-4 */
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{{0x71,0x3d,0x0a,0xd7,0xa3,0x70,0x3d,0x0a,0xd7,0xa3},0x7ff8}, /* 1e-2 */
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{{0xcd,0xcc,0xcc,0xcc,0xcc,0xcc,0xcc,0xcc,0xcc,0xcc},0x7ffb}, /* 1e-1 */
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{{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x80},0x7fff}, /* 1e-0 */
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};
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/* This table contains the powers of ten raised to positive powers of two:
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*
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* entry[12-n] = 10 ** (2 ** n) for 0 <= n <= 12.
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* entry[13] = 1.0
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* entry[-1] = entry[0];
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*
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* There is a -1 entry since it is possible for the algorithm to back up
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* before the table. This -1 entry is created at runtime by duplicating the
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* 0 entry.
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*/
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static /*@only@*/ POT_Entry *POT_TableP;
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static POT_Entry_Source POT_TableP_Source[] = {
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{{0x4c,0xc9,0x9a,0x97,0x20,0x8a,0x02,0x52,0x60,0xc4},0xb525}, /* 1e+4096 */
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{{0x4d,0xa7,0xe4,0x5d,0x3d,0xc5,0x5d,0x3b,0x8b,0x9e},0x9a92}, /* 1e+2048 */
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{{0x0d,0x65,0x17,0x0c,0x75,0x81,0x86,0x75,0x76,0xc9},0x8d48}, /* 1e+1024 */
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{{0x65,0xcc,0xc6,0x91,0x0e,0xa6,0xae,0xa0,0x19,0xe3},0x86a3}, /* 1e+512 */
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{{0xbc,0xdd,0x8d,0xde,0xf9,0x9d,0xfb,0xeb,0x7e,0xaa},0x8351}, /* 1e+256 */
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{{0x6f,0xc6,0xdf,0x8c,0xe9,0x80,0xc9,0x47,0xba,0x93},0x81a8}, /* 1e+128 */
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{{0xbf,0x3c,0xd5,0xa6,0xcf,0xff,0x49,0x1f,0x78,0xc2},0x80d3}, /* 1e+64 */
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{{0x20,0xf0,0x9d,0xb5,0x70,0x2b,0xa8,0xad,0xc5,0x9d},0x8069}, /* 1e+32 */
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{{0x00,0x00,0x00,0x00,0x00,0x04,0xbf,0xc9,0x1b,0x8e},0x8034}, /* 1e+16 */
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{{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x20,0xbc,0xbe},0x8019}, /* 1e+8 */
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{{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x40,0x9c},0x800c}, /* 1e+4 */
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{{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xc8},0x8005}, /* 1e+2 */
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{{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xa0},0x8002}, /* 1e+1 */
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{{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x80},0x7fff}, /* 1e+0 */
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};
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static void
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POT_Table_Init_Entry(/*@out@*/ POT_Entry *e, POT_Entry_Source *s, int dec_exp)
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{
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/* Save decimal exponent */
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e->dec_exponent = dec_exp;
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/* Initialize mantissa */
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e->f.mantissa = BitVector_Create(MANT_BITS, FALSE);
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BitVector_Block_Store(e->f.mantissa, s->mantissa, MANT_BYTES);
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/* Initialize exponent */
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e->f.exponent = s->exponent;
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/* Set sign to 0 (positive) */
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e->f.sign = 0;
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/* Clear flags */
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e->f.flags = 0;
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}
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/*@-compdef@*/
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void
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yasm_floatnum_initialize(void)
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/*@globals undef POT_TableN, undef POT_TableP, POT_TableP_Source,
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POT_TableN_Source @*/
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{
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int dec_exp = 1;
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int i;
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/* Allocate space for two POT tables */
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POT_TableN = yasm_xmalloc(14*sizeof(POT_Entry));
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POT_TableP = yasm_xmalloc(15*sizeof(POT_Entry)); /* note 1 extra for -1 */
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/* Initialize entry[0..12] */
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for (i=12; i>=0; i--) {
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POT_Table_Init_Entry(&POT_TableN[i], &POT_TableN_Source[i], 0-dec_exp);
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POT_Table_Init_Entry(&POT_TableP[i+1], &POT_TableP_Source[i], dec_exp);
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dec_exp *= 2; /* Update decimal exponent */
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}
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/* Initialize entry[13] */
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POT_Table_Init_Entry(&POT_TableN[13], &POT_TableN_Source[13], 0);
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POT_Table_Init_Entry(&POT_TableP[14], &POT_TableP_Source[13], 0);
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/* Initialize entry[-1] for POT_TableP */
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POT_Table_Init_Entry(&POT_TableP[0], &POT_TableP_Source[0], 4096);
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/* Offset POT_TableP so that [0] becomes [-1] */
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POT_TableP++;
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}
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/*@=compdef@*/
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/*@-globstate@*/
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void
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yasm_floatnum_cleanup(void)
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{
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int i;
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/* Un-offset POT_TableP */
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POT_TableP--;
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for (i=0; i<14; i++) {
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BitVector_Destroy(POT_TableN[i].f.mantissa);
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BitVector_Destroy(POT_TableP[i].f.mantissa);
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}
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BitVector_Destroy(POT_TableP[14].f.mantissa);
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yasm_xfree(POT_TableN);
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yasm_xfree(POT_TableP);
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}
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/*@=globstate@*/
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static void
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floatnum_normalize(yasm_floatnum *flt)
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{
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long norm_amt;
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if (BitVector_is_empty(flt->mantissa)) {
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flt->exponent = 0;
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return;
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}
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/* Look for the highest set bit, shift to make it the MSB, and adjust
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* exponent. Don't let exponent go negative. */
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norm_amt = (MANT_BITS-1)-Set_Max(flt->mantissa);
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if (norm_amt > (long)flt->exponent)
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norm_amt = (long)flt->exponent;
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BitVector_Move_Left(flt->mantissa, (N_int)norm_amt);
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flt->exponent -= (unsigned short)norm_amt;
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}
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/* acc *= op */
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static void
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floatnum_mul(yasm_floatnum *acc, const yasm_floatnum *op)
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{
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long expon;
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wordptr product, op1, op2;
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long norm_amt;
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/* Compute the new sign */
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acc->sign ^= op->sign;
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/* Check for multiply by 0 */
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if (BitVector_is_empty(acc->mantissa) || BitVector_is_empty(op->mantissa)) {
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BitVector_Empty(acc->mantissa);
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acc->exponent = EXP_ZERO;
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return;
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}
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/* Add exponents, checking for overflow/underflow. */
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expon = (((int)acc->exponent)-EXP_BIAS) + (((int)op->exponent)-EXP_BIAS);
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expon += EXP_BIAS;
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if (expon > EXP_MAX) {
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/* Overflow; return infinity. */
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BitVector_Empty(acc->mantissa);
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acc->exponent = EXP_INF;
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return;
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} else if (expon < EXP_MIN) {
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/* Underflow; return zero. */
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BitVector_Empty(acc->mantissa);
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acc->exponent = EXP_ZERO;
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return;
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}
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/* Add one to the final exponent, as the multiply shifts one extra time. */
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acc->exponent = (unsigned short)(expon+1);
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/* Allocate space for the multiply result */
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product = BitVector_Create((N_int)((MANT_BITS+1)*2), FALSE);
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/* Allocate 1-bit-longer fields to force the operands to be unsigned */
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op1 = BitVector_Create((N_int)(MANT_BITS+1), FALSE);
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op2 = BitVector_Create((N_int)(MANT_BITS+1), FALSE);
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/* Make the operands unsigned after copying from original operands */
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BitVector_Copy(op1, acc->mantissa);
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BitVector_MSB(op1, 0);
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BitVector_Copy(op2, op->mantissa);
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BitVector_MSB(op2, 0);
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/* Compute the product of the mantissas */
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BitVector_Multiply(product, op1, op2);
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/* Normalize the product. Note: we know the product is non-zero because
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* both of the original operands were non-zero.
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*
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* Look for the highest set bit, shift to make it the MSB, and adjust
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* exponent. Don't let exponent go negative.
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*/
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norm_amt = (MANT_BITS*2-1)-Set_Max(product);
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if (norm_amt > (long)acc->exponent)
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norm_amt = (long)acc->exponent;
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BitVector_Move_Left(product, (N_int)norm_amt);
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acc->exponent -= (unsigned short)norm_amt;
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/* Store the highest bits of the result */
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BitVector_Interval_Copy(acc->mantissa, product, 0, MANT_BITS, MANT_BITS);
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/* Free allocated variables */
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BitVector_Destroy(product);
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BitVector_Destroy(op1);
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BitVector_Destroy(op2);
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}
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yasm_floatnum *
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yasm_floatnum_create(const char *str)
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{
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yasm_floatnum *flt;
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int dec_exponent, dec_exp_add; /* decimal (powers of 10) exponent */
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int POT_index;
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wordptr operand[2];
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int sig_digits;
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int decimal_pt;
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boolean carry;
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flt = yasm_xmalloc(sizeof(yasm_floatnum));
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flt->mantissa = BitVector_Create(MANT_BITS, TRUE);
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/* allocate and initialize calculation variables */
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operand[0] = BitVector_Create(MANT_BITS, TRUE);
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operand[1] = BitVector_Create(MANT_BITS, TRUE);
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dec_exponent = 0;
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sig_digits = 0;
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decimal_pt = 1;
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/* set initial flags to 0 */
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flt->flags = 0;
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/* check for + or - character and skip */
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if (*str == '-') {
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flt->sign = 1;
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str++;
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} else if (*str == '+') {
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flt->sign = 0;
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str++;
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} else
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flt->sign = 0;
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/* eliminate any leading zeros (which do not count as significant digits) */
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while (*str == '0')
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str++;
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/* When we reach the end of the leading zeros, first check for a decimal
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* point. If the number is of the form "0---0.0000" we need to get rid
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* of the zeros after the decimal point and not count them as significant
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* digits.
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*/
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if (*str == '.') {
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str++;
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while (*str == '0') {
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str++;
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dec_exponent--;
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}
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} else {
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/* The number is of the form "yyy.xxxx" (where y <> 0). */
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while (isdigit(*str)) {
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/* See if we've processed more than the max significant digits: */
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if (sig_digits < MANT_SIGDIGITS) {
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/* Multiply mantissa by 10 [x = (x<<1)+(x<<3)] */
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BitVector_shift_left(flt->mantissa, 0);
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BitVector_Copy(operand[0], flt->mantissa);
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BitVector_Move_Left(flt->mantissa, 2);
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carry = 0;
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BitVector_add(operand[1], operand[0], flt->mantissa, &carry);
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/* Add in current digit */
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BitVector_Empty(operand[0]);
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BitVector_Chunk_Store(operand[0], 4, 0, (N_long)(*str-'0'));
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carry = 0;
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BitVector_add(flt->mantissa, operand[1], operand[0], &carry);
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} else {
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/* Can't integrate more digits with mantissa, so instead just
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* raise by a power of ten.
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*/
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dec_exponent++;
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}
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sig_digits++;
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str++;
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}
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if (*str == '.')
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str++;
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else
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decimal_pt = 0;
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}
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if (decimal_pt) {
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/* Process the digits to the right of the decimal point. */
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while (isdigit(*str)) {
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/* See if we've processed more than 19 significant digits: */
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if (sig_digits < 19) {
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/* Raise by a power of ten */
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dec_exponent--;
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/* Multiply mantissa by 10 [x = (x<<1)+(x<<3)] */
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BitVector_shift_left(flt->mantissa, 0);
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BitVector_Copy(operand[0], flt->mantissa);
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BitVector_Move_Left(flt->mantissa, 2);
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carry = 0;
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BitVector_add(operand[1], operand[0], flt->mantissa, &carry);
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/* Add in current digit */
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BitVector_Empty(operand[0]);
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BitVector_Chunk_Store(operand[0], 4, 0, (N_long)(*str-'0'));
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carry = 0;
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BitVector_add(flt->mantissa, operand[1], operand[0], &carry);
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}
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sig_digits++;
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str++;
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}
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}
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if (*str == 'e' || *str == 'E') {
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str++;
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/* We just saw the "E" character, now read in the exponent value and
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* add it into dec_exponent.
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*/
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dec_exp_add = 0;
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sscanf(str, "%d", &dec_exp_add);
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dec_exponent += dec_exp_add;
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}
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/* Free calculation variables. */
|
|
BitVector_Destroy(operand[1]);
|
|
BitVector_Destroy(operand[0]);
|
|
|
|
/* Normalize the number, checking for 0 first. */
|
|
if (BitVector_is_empty(flt->mantissa)) {
|
|
/* Mantissa is 0, zero exponent too. */
|
|
flt->exponent = 0;
|
|
/* Set zero flag so output functions don't see 0 value as underflow. */
|
|
flt->flags |= FLAG_ISZERO;
|
|
/* Return 0 value. */
|
|
return flt;
|
|
}
|
|
/* Exponent if already norm. */
|
|
flt->exponent = (unsigned short)(0x7FFF+(MANT_BITS-1));
|
|
floatnum_normalize(flt);
|
|
|
|
/* The number is normalized. Now multiply by 10 the number of times
|
|
* specified in DecExponent. This uses the power of ten tables to speed
|
|
* up this operation (and make it more accurate).
|
|
*/
|
|
if (dec_exponent > 0) {
|
|
POT_index = 0;
|
|
/* Until we hit 1.0 or finish exponent or overflow */
|
|
while ((POT_index < 14) && (dec_exponent != 0) &&
|
|
(flt->exponent != EXP_INF)) {
|
|
/* Find the first power of ten in the table which is just less than
|
|
* the exponent.
|
|
*/
|
|
while (dec_exponent < POT_TableP[POT_index].dec_exponent)
|
|
POT_index++;
|
|
|
|
if (POT_index < 14) {
|
|
/* Subtract out what we're multiplying in from exponent */
|
|
dec_exponent -= POT_TableP[POT_index].dec_exponent;
|
|
|
|
/* Multiply by current power of 10 */
|
|
floatnum_mul(flt, &POT_TableP[POT_index].f);
|
|
}
|
|
}
|
|
} else if (dec_exponent < 0) {
|
|
POT_index = 0;
|
|
/* Until we hit 1.0 or finish exponent or underflow */
|
|
while ((POT_index < 14) && (dec_exponent != 0) &&
|
|
(flt->exponent != EXP_ZERO)) {
|
|
/* Find the first power of ten in the table which is just less than
|
|
* the exponent.
|
|
*/
|
|
while (dec_exponent > POT_TableN[POT_index].dec_exponent)
|
|
POT_index++;
|
|
|
|
if (POT_index < 14) {
|
|
/* Subtract out what we're multiplying in from exponent */
|
|
dec_exponent -= POT_TableN[POT_index].dec_exponent;
|
|
|
|
/* Multiply by current power of 10 */
|
|
floatnum_mul(flt, &POT_TableN[POT_index].f);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Round the result. (Don't round underflow or overflow). Also don't
|
|
* increment if this would cause the mantissa to wrap.
|
|
*/
|
|
if ((flt->exponent != EXP_INF) && (flt->exponent != EXP_ZERO) &&
|
|
!BitVector_is_full(flt->mantissa))
|
|
BitVector_increment(flt->mantissa);
|
|
|
|
return flt;
|
|
}
|
|
|
|
yasm_floatnum *
|
|
yasm_floatnum_copy(const yasm_floatnum *flt)
|
|
{
|
|
yasm_floatnum *f = yasm_xmalloc(sizeof(yasm_floatnum));
|
|
|
|
f->mantissa = BitVector_Clone(flt->mantissa);
|
|
f->exponent = flt->exponent;
|
|
f->sign = flt->sign;
|
|
f->flags = flt->flags;
|
|
|
|
return f;
|
|
}
|
|
|
|
void
|
|
yasm_floatnum_destroy(yasm_floatnum *flt)
|
|
{
|
|
BitVector_Destroy(flt->mantissa);
|
|
yasm_xfree(flt);
|
|
}
|
|
|
|
int
|
|
yasm_floatnum_calc(yasm_floatnum *acc, yasm_expr_op op,
|
|
/*@unused@*/ yasm_floatnum *operand)
|
|
{
|
|
if (op != YASM_EXPR_NEG) {
|
|
yasm_error_set(YASM_ERROR_FLOATING_POINT,
|
|
N_("Unsupported floating-point arithmetic operation"));
|
|
return 1;
|
|
}
|
|
acc->sign ^= 1;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
yasm_floatnum_get_int(const yasm_floatnum *flt, unsigned long *ret_val)
|
|
{
|
|
unsigned char t[4];
|
|
|
|
if (yasm_floatnum_get_sized(flt, t, 4, 32, 0, 0, 0)) {
|
|
*ret_val = 0xDEADBEEFUL; /* Obviously incorrect return value */
|
|
return 1;
|
|
}
|
|
|
|
YASM_LOAD_32_L(*ret_val, &t[0]);
|
|
return 0;
|
|
}
|
|
|
|
/* Function used by conversion routines to actually perform the conversion.
|
|
*
|
|
* ptr -> the array to return the little-endian floating point value into.
|
|
* flt -> the floating point value to convert.
|
|
* byte_size -> the size in bytes of the output format.
|
|
* mant_bits -> the size in bits of the output mantissa.
|
|
* implicit1 -> does the output format have an implicit 1? 1=yes, 0=no.
|
|
* exp_bits -> the size in bits of the output exponent.
|
|
*
|
|
* Returns 0 on success, 1 if overflow, -1 if underflow.
|
|
*/
|
|
static int
|
|
floatnum_get_common(const yasm_floatnum *flt, /*@out@*/ unsigned char *ptr,
|
|
N_int byte_size, N_int mant_bits, int implicit1,
|
|
N_int exp_bits)
|
|
{
|
|
long exponent = (long)flt->exponent;
|
|
wordptr output;
|
|
charptr buf;
|
|
unsigned int len;
|
|
unsigned int overflow = 0, underflow = 0;
|
|
int retval = 0;
|
|
long exp_bias = (1<<(exp_bits-1))-1;
|
|
long exp_inf = (1<<exp_bits)-1;
|
|
|
|
output = BitVector_Create(byte_size*8, TRUE);
|
|
|
|
/* copy mantissa */
|
|
BitVector_Interval_Copy(output, flt->mantissa, 0,
|
|
(N_int)((MANT_BITS-implicit1)-mant_bits),
|
|
mant_bits);
|
|
|
|
/* round mantissa */
|
|
if (BitVector_bit_test(flt->mantissa, (MANT_BITS-implicit1)-(mant_bits+1)))
|
|
BitVector_increment(output);
|
|
|
|
if (BitVector_bit_test(output, mant_bits)) {
|
|
/* overflowed, so zero mantissa (and set explicit bit if necessary) */
|
|
BitVector_Empty(output);
|
|
BitVector_Bit_Copy(output, mant_bits-1, !implicit1);
|
|
/* and up the exponent (checking for overflow) */
|
|
if (exponent+1 >= EXP_INF)
|
|
overflow = 1;
|
|
else
|
|
exponent++;
|
|
}
|
|
|
|
/* adjust the exponent to the output bias, checking for overflow */
|
|
exponent -= EXP_BIAS-exp_bias;
|
|
if (exponent >= exp_inf)
|
|
overflow = 1;
|
|
else if (exponent <= 0)
|
|
underflow = 1;
|
|
|
|
/* underflow and overflow both set!? */
|
|
if (underflow && overflow)
|
|
yasm_internal_error(N_("Both underflow and overflow set"));
|
|
|
|
/* check for underflow or overflow and set up appropriate output */
|
|
if (underflow) {
|
|
BitVector_Empty(output);
|
|
exponent = 0;
|
|
if (!(flt->flags & FLAG_ISZERO))
|
|
retval = -1;
|
|
} else if (overflow) {
|
|
BitVector_Empty(output);
|
|
exponent = exp_inf;
|
|
retval = 1;
|
|
}
|
|
|
|
/* move exponent into place */
|
|
BitVector_Chunk_Store(output, exp_bits, mant_bits, (N_long)exponent);
|
|
|
|
/* merge in sign bit */
|
|
BitVector_Bit_Copy(output, byte_size*8-1, flt->sign);
|
|
|
|
/* get little-endian bytes */
|
|
buf = BitVector_Block_Read(output, &len);
|
|
if (len < byte_size)
|
|
yasm_internal_error(
|
|
N_("Byte length of BitVector does not match bit length"));
|
|
|
|
/* copy to output */
|
|
memcpy(ptr, buf, byte_size*sizeof(unsigned char));
|
|
|
|
/* free allocated resources */
|
|
yasm_xfree(buf);
|
|
|
|
BitVector_Destroy(output);
|
|
|
|
return retval;
|
|
}
|
|
|
|
/* IEEE-754r "half precision" format:
|
|
* 16 bits:
|
|
* 15 9 Bit 0
|
|
* | | |
|
|
* seee eemm mmmm mmmm
|
|
*
|
|
* e = bias 15 exponent
|
|
* s = sign bit
|
|
* m = mantissa bits, bit 10 is an implied one bit.
|
|
*
|
|
* IEEE-754 (Intel) "single precision" format:
|
|
* 32 bits:
|
|
* Bit 31 Bit 22 Bit 0
|
|
* | | |
|
|
* seeeeeee emmmmmmm mmmmmmmm mmmmmmmm
|
|
*
|
|
* e = bias 127 exponent
|
|
* s = sign bit
|
|
* m = mantissa bits, bit 23 is an implied one bit.
|
|
*
|
|
* IEEE-754 (Intel) "double precision" format:
|
|
* 64 bits:
|
|
* bit 63 bit 51 bit 0
|
|
* | | |
|
|
* seeeeeee eeeemmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm
|
|
*
|
|
* e = bias 1023 exponent.
|
|
* s = sign bit.
|
|
* m = mantissa bits. Bit 52 is an implied one bit.
|
|
*
|
|
* IEEE-754 (Intel) "extended precision" format:
|
|
* 80 bits:
|
|
* bit 79 bit 63 bit 0
|
|
* | | |
|
|
* seeeeeee eeeeeeee mmmmmmmm m...m m...m m...m m...m m...m
|
|
*
|
|
* e = bias 16383 exponent
|
|
* m = 64 bit mantissa with NO implied bit!
|
|
* s = sign (for mantissa)
|
|
*/
|
|
int
|
|
yasm_floatnum_get_sized(const yasm_floatnum *flt, unsigned char *ptr,
|
|
size_t destsize, size_t valsize, size_t shift,
|
|
int bigendian, int warn)
|
|
{
|
|
int retval;
|
|
if (destsize*8 != valsize || shift>0 || bigendian) {
|
|
/* TODO */
|
|
yasm_internal_error(N_("unsupported floatnum functionality"));
|
|
}
|
|
switch (destsize) {
|
|
case 2:
|
|
retval = floatnum_get_common(flt, ptr, 2, 10, 1, 5);
|
|
break;
|
|
case 4:
|
|
retval = floatnum_get_common(flt, ptr, 4, 23, 1, 8);
|
|
break;
|
|
case 8:
|
|
retval = floatnum_get_common(flt, ptr, 8, 52, 1, 11);
|
|
break;
|
|
case 10:
|
|
retval = floatnum_get_common(flt, ptr, 10, 64, 0, 15);
|
|
break;
|
|
default:
|
|
yasm_internal_error(N_("Invalid float conversion size"));
|
|
/*@notreached@*/
|
|
return 1;
|
|
}
|
|
if (warn) {
|
|
if (retval < 0)
|
|
yasm_warn_set(YASM_WARN_GENERAL,
|
|
N_("underflow in floating point expression"));
|
|
else if (retval > 0)
|
|
yasm_warn_set(YASM_WARN_GENERAL,
|
|
N_("overflow in floating point expression"));
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
/* 1 if the size is valid, 0 if it isn't */
|
|
int
|
|
yasm_floatnum_check_size(/*@unused@*/ const yasm_floatnum *flt, size_t size)
|
|
{
|
|
switch (size) {
|
|
case 16:
|
|
case 32:
|
|
case 64:
|
|
case 80:
|
|
return 1;
|
|
default:
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
void
|
|
yasm_floatnum_print(const yasm_floatnum *flt, FILE *f)
|
|
{
|
|
unsigned char out[10];
|
|
unsigned char *str;
|
|
int i;
|
|
|
|
/* Internal format */
|
|
str = BitVector_to_Hex(flt->mantissa);
|
|
fprintf(f, "%c %s *2^%04x\n", flt->sign?'-':'+', (char *)str,
|
|
flt->exponent);
|
|
yasm_xfree(str);
|
|
|
|
/* 32-bit (single precision) format */
|
|
fprintf(f, "32-bit: %d: ",
|
|
yasm_floatnum_get_sized(flt, out, 4, 32, 0, 0, 0));
|
|
for (i=0; i<4; i++)
|
|
fprintf(f, "%02x ", out[i]);
|
|
fprintf(f, "\n");
|
|
|
|
/* 64-bit (double precision) format */
|
|
fprintf(f, "64-bit: %d: ",
|
|
yasm_floatnum_get_sized(flt, out, 8, 64, 0, 0, 0));
|
|
for (i=0; i<8; i++)
|
|
fprintf(f, "%02x ", out[i]);
|
|
fprintf(f, "\n");
|
|
|
|
/* 80-bit (extended precision) format */
|
|
fprintf(f, "80-bit: %d: ",
|
|
yasm_floatnum_get_sized(flt, out, 10, 80, 0, 0, 0));
|
|
for (i=0; i<10; i++)
|
|
fprintf(f, "%02x ", out[i]);
|
|
fprintf(f, "\n");
|
|
}
|