WebSVN – HelenOS – Diff – /SPARTAN/trunk/arch/ia32/src/fmath.c

 /*
  * Copyright (C) 2005 Josef Cejka
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
+ *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  * - Redistributions in binary form must reproduce the above copyright
  *   notice, this list of conditions and the following disclaimer in the
  *   documentation and/or other materials provided with the distribution.
  * - The name of the author may not be used to endorse or promote products
  *   derived from this software without specific prior written permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include <arch/fmath.h>
 #include <print.h>
 #define FMATH_MANTISA_MASK ( 0x000fffffffffffffLL )
-int fmath_is_negative(double num)
+#define FMATH_NAN ( 0x0001000000000001LL )
-{
-    fmath_ld_union_t fmath_ld_union;
-    fmath_ld_union.bf = num;
-    return ((fmath_ld_union.ldd[7])&0x80)==0x80; /*first bit is sign, IA32 is little endian -> 8th byte*/
-}
 signed short fmath_get_binary_exponent(double num)
+{
     fmath_ld_union_t fmath_ld_union;
     fmath_ld_union.bf = num;
     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 */
+}
 double fmath_get_decimal_exponent(double num)
+{
     double value;
     /* log10(2)*log2(x) => log10(x) */
     __asm__ __volatile__ ( \
     "fldlg2     #load log10(2)  \n\t"   \
     "fxch %%st(1)       \n\t" \
     "fyl2x      #count st(0)*log2(st(1))->st(1); pop st(0)  \n\t" \
     : "=t" (value) : "0"(num) );
     return value;
+}
 __u64 fmath_get_binary_mantisa(double num)
+{
     union { __u64 _u; double _d;} un = { _d : num };
     un._u=un._u &(FMATH_MANTISA_MASK); /* mask 52 bits of mantisa*/
     return un._u;
+}
 double fmath_fint(double num, double *intp)
+{
     fmath_ld_union_t fmath_ld_union_num;
     fmath_ld_union_t fmath_ld_union_int;
     signed short exp;
     __u64 mask,mantisa;
     int i;
     exp=fmath_get_binary_exponent(num);
     if (exp<0) {
         *intp = 0.0;
-        *intp = fmath_set_sign(0.0L,fmath_is_negative(num));
         return num;
+        }
     if (exp>51) {
         *intp=num;
         num=0.0;
-        num= fmath_set_sign(0.0L,fmath_is_negative(*intp));
         return num;
+    }
     fmath_ld_union_num.bf = num;
     mask = FMATH_MANTISA_MASK>>exp;
     //mantisa = (fmath_get-binary_mantisa(num))&(~mask);
     for (i=0;i<7;i++) {
         /* Ugly construction for obtain sign, exponent and integer part from num */
         fmath_ld_union_int.ldd[i]=fmath_ld_union_num.ldd[i]&(((~mask)>>(i*8))&0xff);
+    }
     fmath_ld_union_int.ldd[6]|=((fmath_ld_union_num.ldd[6])&(0xf0));
     fmath_ld_union_int.ldd[7]=fmath_ld_union_num.ldd[7];
     *intp=fmath_ld_union_int.bf;
     return fmath_ld_union_num.bf-fmath_ld_union_int.bf;
 };
-double fmath_set_sign(double num,__u8 sign)
-{
-    fmath_ld_union_t fmath_ld_union;
-    fmath_ld_union.bf = num;
-    fmath_ld_union.ldd[7]=((fmath_ld_union.ldd[7])&0x7f)|(sign<<7); /* change 64th bit (IA32 is a little endian)*/
-    return fmath_ld_union.bf;
-}
-double fmath_abs(double num)
-{
-    return fmath_set_sign(num,0);
-}
 double fmath_dpow(double base, double exponent)
+{
     double value=1.0;
     if (base<=0.0) return base;
     //2^(x*log2(10)) = 2^y = 10^x
     __asm__ __volatile__ (      \
         "fyl2x # ST(1):=ST(1)*log2(ST(0)), pop st(0) \n\t "     \
         "fld    %%st(0) \n\t"   \
         "frndint \n\t"      \
         "fxch %%st(1) \n\t"     \
         "fsub %%st(1),%%st(0) \n\t" \
         "f2xm1  # ST := 2^ST -1\n\t"            \
         "fld1 \n\t"         \
         "faddp %%st(0),%%st(1) \n\t"    \
         "fscale #ST:=ST*2^(ST(1))\n\t"      \
         "fstp %%st(1) \n\t"     \
     "" : "=t" (value) :  "0" (base), "u" (exponent) );
     return value;
+}
+int fmath_is_nan(double num)
+{
+    __u16 exp;
+    fmath_ld_union_t fmath_ld_union;
+    fmath_ld_union.bf = num;
+    exp=(((fmath_ld_union.ldd[7])&0x7f)<<4) + (((fmath_ld_union.ldd[6])&0xf0)>>4); /* exponent is 11 bits lenght, so sevent bits is in 8th byte and 4 bits in 7th */
+    if (exp!=0x07ff) return 0;
+    if (fmath_get_binary_mantisa(num)>=FMATH_NAN) return 1;
+    return 0;
+}
+int fmath_is_infinity(double num)
+{
+    __u16 exp;
+    fmath_ld_union_t fmath_ld_union;
+    fmath_ld_union.bf = num;
+    exp=(((fmath_ld_union.ldd[7])&0x7f)<<4) + (((fmath_ld_union.ldd[6])&0xf0)>>4); /* exponent is 11 bits lenght, so sevent bits is in 8th byte and 4 bits in 7th */
+    if (exp!=0x07ff) return 0;
+    if (fmath_get_binary_mantisa(num)==0x0) return 1;
+    return 0;
+}

Subversion Repositories HelenOS

(root)/SPARTAN/trunk/arch/ia32/src/fmath.c @ 302 – Rev 230 → 266