Rev 266 | Go to most recent revision | Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 230 | cejka | 1 | /* |
| 2 | * Copyright (C) 2005 Josef Cejka |
||
| 3 | * All rights reserved. |
||
| 4 | * |
||
| 5 | * Redistribution and use in source and binary forms, with or without |
||
| 6 | * modification, are permitted provided that the following conditions |
||
| 7 | * are met: |
||
| 8 | * |
||
| 9 | * - Redistributions of source code must retain the above copyright |
||
| 10 | * notice, this list of conditions and the following disclaimer. |
||
| 11 | * - Redistributions in binary form must reproduce the above copyright |
||
| 12 | * notice, this list of conditions and the following disclaimer in the |
||
| 13 | * documentation and/or other materials provided with the distribution. |
||
| 14 | * - The name of the author may not be used to endorse or promote products |
||
| 15 | * derived from this software without specific prior written permission. |
||
| 16 | * |
||
| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
||
| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
||
| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
||
| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
||
| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
||
| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
||
| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
||
| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
||
| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
||
| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
||
| 27 | */ |
||
| 28 | |||
| 29 | #include <arch/fmath.h> |
||
| 30 | #include <print.h> |
||
| 31 | |||
| 32 | #define FMATH_MANTISA_MASK ( 0x000fffffffffffffLL ) |
||
| 33 | |||
| 34 | int fmath_is_negative(double num) |
||
| 35 | { |
||
| 36 | fmath_ld_union_t fmath_ld_union; |
||
| 37 | fmath_ld_union.bf = num; |
||
| 38 | return ((fmath_ld_union.ldd[7])&0x80)==0x80; /*first bit is sign, IA32 is little endian -> 8th byte*/ |
||
| 39 | |||
| 40 | } |
||
| 41 | |||
| 42 | signed short fmath_get_binary_exponent(double num) |
||
| 43 | { |
||
| 44 | fmath_ld_union_t fmath_ld_union; |
||
| 45 | fmath_ld_union.bf = num; |
||
| 46 | return (signed short)((((fmath_ld_union.ldd[7])&0x7f)<<4) + (((fmath_ld_union.ldd[6])&0xf0)>>4)) -FMATH_EXPONENT_BIAS; /* exponent is 11 bits lenght, so sevent bits is in 8th byte and 4 bits in 7th */ |
||
| 47 | } |
||
| 48 | |||
| 49 | double fmath_get_decimal_exponent(double num) |
||
| 50 | { |
||
| 51 | double value; |
||
| 52 | /* log10(2)*log2(x) => log10(x) */ |
||
| 53 | __asm__ __volatile__ ( \ |
||
| 54 | "fldlg2 #load log10(2) \n\t" \ |
||
| 55 | "fxch %%st(1) \n\t" \ |
||
| 56 | "fyl2x #count st(0)*log2(st(1))->st(1); pop st(0) \n\t" \ |
||
| 57 | : "=t" (value) : "0"(num) ); |
||
| 58 | return value; |
||
| 59 | } |
||
| 60 | |||
| 61 | __u64 fmath_get_binary_mantisa(double num) |
||
| 62 | { |
||
| 63 | union { __u64 _u; double _d;} un = { _d : num }; |
||
| 64 | un._u=un._u &(FMATH_MANTISA_MASK); /* mask 52 bits of mantisa*/ |
||
| 65 | return un._u; |
||
| 66 | } |
||
| 67 | |||
| 68 | double fmath_fint(double num, double *intp) |
||
| 69 | { |
||
| 70 | fmath_ld_union_t fmath_ld_union_num; |
||
| 71 | fmath_ld_union_t fmath_ld_union_int; |
||
| 72 | signed short exp; |
||
| 73 | __u64 mask,mantisa; |
||
| 74 | int i; |
||
| 75 | |||
| 76 | exp=fmath_get_binary_exponent(num); |
||
| 77 | |||
| 78 | if (exp<0) { |
||
| 79 | *intp = 0.0; |
||
| 80 | *intp = fmath_set_sign(0.0L,fmath_is_negative(num)); |
||
| 81 | return num; |
||
| 82 | } |
||
| 83 | |||
| 84 | |||
| 85 | if (exp>51) { |
||
| 86 | *intp=num; |
||
| 87 | num=0.0; |
||
| 88 | num= fmath_set_sign(0.0L,fmath_is_negative(*intp)); |
||
| 89 | return num; |
||
| 90 | } |
||
| 91 | |||
| 92 | fmath_ld_union_num.bf = num; |
||
| 93 | |||
| 94 | mask = FMATH_MANTISA_MASK>>exp; |
||
| 95 | //mantisa = (fmath_get-binary_mantisa(num))&(~mask); |
||
| 96 | |||
| 97 | for (i=0;i<7;i++) { |
||
| 98 | /* Ugly construction for obtain sign, exponent and integer part from num */ |
||
| 99 | fmath_ld_union_int.ldd[i]=fmath_ld_union_num.ldd[i]&(((~mask)>>(i*8))&0xff); |
||
| 100 | } |
||
| 101 | |||
| 102 | fmath_ld_union_int.ldd[6]|=((fmath_ld_union_num.ldd[6])&(0xf0)); |
||
| 103 | fmath_ld_union_int.ldd[7]=fmath_ld_union_num.ldd[7]; |
||
| 104 | |||
| 105 | *intp=fmath_ld_union_int.bf; |
||
| 106 | return fmath_ld_union_num.bf-fmath_ld_union_int.bf; |
||
| 107 | }; |
||
| 108 | |||
| 109 | double fmath_set_sign(double num,__u8 sign) |
||
| 110 | { |
||
| 111 | fmath_ld_union_t fmath_ld_union; |
||
| 112 | fmath_ld_union.bf = num; |
||
| 113 | fmath_ld_union.ldd[7]=((fmath_ld_union.ldd[7])&0x7f)|(sign<<7); /* change 64th bit (IA32 is a little endian)*/ |
||
| 114 | return fmath_ld_union.bf; |
||
| 115 | } |
||
| 116 | |||
| 117 | double fmath_abs(double num) |
||
| 118 | { |
||
| 119 | return fmath_set_sign(num,0); |
||
| 120 | } |
||
| 121 | |||
| 122 | double fmath_dpow(double base, double exponent) |
||
| 123 | { |
||
| 124 | double value=1.0; |
||
| 125 | if (base<=0.0) return base; |
||
| 126 | |||
| 127 | //2^(x*log2(10)) = 2^y = 10^x |
||
| 128 | |||
| 129 | __asm__ __volatile__ ( \ |
||
| 130 | "fyl2x # ST(1):=ST(1)*log2(ST(0)), pop st(0) \n\t " \ |
||
| 131 | "fld %%st(0) \n\t" \ |
||
| 132 | "frndint \n\t" \ |
||
| 133 | "fxch %%st(1) \n\t" \ |
||
| 134 | "fsub %%st(1),%%st(0) \n\t" \ |
||
| 135 | "f2xm1 # ST := 2^ST -1\n\t" \ |
||
| 136 | "fld1 \n\t" \ |
||
| 137 | "faddp %%st(0),%%st(1) \n\t" \ |
||
| 138 | "fscale #ST:=ST*2^(ST(1))\n\t" \ |
||
| 139 | "fstp %%st(1) \n\t" \ |
||
| 140 | "" : "=t" (value) : "0" (base), "u" (exponent) ); |
||
| 141 | return value; |
||
| 142 | } |
||
| 143 |