static DEC_TYPE
IEEE_FUNCTION_NAME (DEC_TYPE x)
{
decContext context;
decNumber dn_result;
DEC_TYPE result;
decNumber dn_x;
decNumber dn_two;
DEC_TYPE two = DFP_CONSTANT(2.0);
FUNC_CONVERT_TO_DN (&two, &dn_two);
FUNC_CONVERT_TO_DN (&x, &dn_x);
if (decNumberIsNaN (&dn_x))
return x+x;
if (decNumberIsInfinite (&dn_x) )
return decNumberIsNegative (&dn_x) ? DFP_CONSTANT(0.0) : x;
decContextDefault (&context, DEFAULT_CONTEXT);
/* decNumberPow (&dn_result, &dn_two, &dn_x, &context); */
decNumberPower (&dn_result, &dn_two, &dn_x, &context);
FUNC_CONVERT_FROM_DN (&dn_result, &result, &context);
if(context.status & DEC_Overflow)
DFP_EXCEPT (FE_OVERFLOW);
return result;
}
void zetadk(decNumber *dk, int n, int k, decContext *ctx) {
int i;
decNumber t, r, s, v, sum, const_4;
int_to_dn(&const_4, 4, ctx);
decNumberZero(&sum);
for (i=0; i<=k; i++) {
int_to_dn(&t, n+i-1, ctx);
decNumberFactorial(&s, &t, ctx);
int_to_dn(&t, i, ctx);
decNumberPower(&r, &const_4, &t, ctx);
decNumberMultiply(&v, &s, &r, ctx);
int_to_dn(&t, n-i, ctx);
decNumberFactorial(&s, &t, ctx);
int_to_dn(&t, 2*i, ctx);
decNumberFactorial(&r, &t, ctx);
decNumberMultiply(&t, &r, &s, ctx);
decNumberDivide(&r, &v, &t, ctx);
decNumberAdd(&sum, &sum, &r, ctx);
}
int_to_dn(&t, n, ctx);
#if 1
// Don't bother rounding to int, the conversion in compile_consts
// will do this if required due to the extra precision being carries.
decNumberMultiply(dk, &t, &sum, ctx);
#else
// We can round this to integers this way....
decNumberMultiply(&s, &t, &sum, ctx);
decNumberToIntegralValue(dk, &s, ctx);
#endif
}
DecimalDecNumber power(const DecimalDecNumber &val, int32 exponent)
{
decNumber dExponent;
decNumberFromInt32(&dExponent, exponent);
DecimalDecNumber result;
decNumberPower(&result.m_value, &val.m_value, &dExponent, &val.m_context);
return result;
}
void* decSinglePower (void* _0, const void* _1, const void* _2, decContext* ctx) noexcept
{
decNumber _0num;
decNumber _1num;
decNumber _2num;
decSingleToNumber (_1, &_1num);
decSingleToNumber (_2, &_2num);
decNumberPower (&_0num, &_1num, &_2num, ctx);
return decSingleFromNumber (_0, &_0num, ctx);
}
int main(int argc, char *argv[]) {
{ // excerpt for User's Guide starts here--------------------------|
decNumber one, mtwo, hundred; // constants
decNumber start, rate, years; // parameters
decNumber total; // result
decContext set; // working context
uint8_t startpack[]={0x01, 0x00, 0x00, 0x0C}; // investment=100000
int32_t startscale=0;
uint8_t ratepack[]={0x06, 0x5C}; // rate=6.5%
int32_t ratescale=1;
uint8_t yearspack[]={0x02, 0x0C}; // years=20
int32_t yearsscale=0;
uint8_t respack[16]; // result, packed
int32_t resscale; // ..
char hexes[49]; // for packed->hex
int i; // counter
if (argc<0) printf("%s", argv[1]); // noop for warning
decContextDefault(&set, DEC_INIT_BASE); // initialize
set.traps=0; // no traps
set.digits=25; // precision 25
decNumberFromString(&one, "1", &set); // set constants
decNumberFromString(&mtwo, "-2", &set);
decNumberFromString(&hundred, "100", &set);
decPackedToNumber(startpack, sizeof(startpack), &startscale, &start);
decPackedToNumber(ratepack, sizeof(ratepack), &ratescale, &rate);
decPackedToNumber(yearspack, sizeof(yearspack), &yearsscale, &years);
decNumberDivide(&rate, &rate, &hundred, &set); // rate=rate/100
decNumberAdd(&rate, &rate, &one, &set); // rate=rate+1
decNumberPower(&rate, &rate, &years, &set); // rate=rate^years
decNumberMultiply(&total, &rate, &start, &set); // total=rate*start
decNumberRescale(&total, &total, &mtwo, &set); // two digits please
decPackedFromNumber(respack, sizeof(respack), &resscale, &total);
// lay out the total as sixteen hexadecimal pairs
for (i=0; i<16; i++) {
sprintf(&hexes[i*3], "%02x ", respack[i]);
}
printf("Result: %s (scale=%ld)\n", hexes, (long int)resscale);
} //---------------------------------------------------------------|
return 0;
} // main
int main(int argc, char *argv[]) {
int need=3;
if (argc<need+1) { // not enough words
printf("Please supply %d number(s).\n", need);
return 1;
}
{ // excerpt for User's Guide starts here--------------------------|
decNumber one, mtwo, hundred; // constants
decNumber start, rate, years; // parameters
decNumber total; // result
decContext set; // working context
char string[DECNUMDIGITS+14]; // conversion buffer
decContextDefault(&set, DEC_INIT_BASE); // initialize
set.traps=0; // no traps
set.digits=25; // precision 25
decNumberFromString(&one, "1", &set); // set constants
decNumberFromString(&mtwo, "-2", &set);
decNumberFromString(&hundred, "100", &set);
decNumberFromString(&start, argv[1], &set); // parameter words
decNumberFromString(&rate, argv[2], &set);
decNumberFromString(&years, argv[3], &set);
decNumberDivide(&rate, &rate, &hundred, &set); // rate=rate/100
decNumberAdd(&rate, &rate, &one, &set); // rate=rate+1
decNumberPower(&rate, &rate, &years, &set); // rate=rate^years
decNumberMultiply(&total, &rate, &start, &set); // total=rate*start
decNumberRescale(&total, &total, &mtwo, &set); // two digits please
decNumberToString(&total, string);
printf("%s at %s%% for %s years => %s\n",
argv[1], argv[2], argv[3], string);
} //---------------------------------------------------------------|
return 0;
} // main
int main(int argc, char *argv[]) {
decQuad a; // working decQuad
decNumber numa, numb; // working decNumbers
decContext set; // working context
char string[DECQUAD_String]; // number->string buffer
if (argc<3) { // not enough words
printf("Please supply two numbers for power(2*a, b).\n");
return 1;
}
decContextDefault(&set, DEC_INIT_DECQUAD); // initialize
decQuadFromString(&a, argv[1], &set); // get a
decQuadAdd(&a, &a, &a, &set); // double a
decQuadToNumber(&a, &numa); // convert to decNumber
decNumberFromString(&numb, argv[2], &set);
decNumberPower(&numa, &numa, &numb, &set); // numa=numa**numb
decQuadFromNumber(&a, &numa, &set); // back via a Quad
decQuadToString(&a, string); // ..
printf("power(2*%s, %s) => %s\n", argv[1], argv[2], string);
return 0;
} // main
static DEC_TYPE
IEEE_FUNCTION_NAME (DEC_TYPE x, DEC_TYPE y)
{
decContext context;
decNumber dn_result;
DEC_TYPE result;
DEC_TYPE absx;
decNumber dn_x;
decNumber dn_absx;
decNumber dn_y;
decNumber dn_one;
decNumber dn_two;
decNumber dn_temp;
decNumber dn_temp2;
decNumber dn_temp3;
int y_is_int;
int y_is_oddint=0;
int abs_x_vs_1;
DEC_TYPE one = DFP_CONSTANT(1.0);
DEC_TYPE two = DFP_CONSTANT(2.0);
FUNC_CONVERT_TO_DN (&x, &dn_x);
FUNC_CONVERT_TO_DN (&y, &dn_y);
FUNC_CONVERT_TO_DN (&one, &dn_one);
decContextDefault (&context, DEFAULT_CONTEXT);
if (decNumberIsZero (&dn_y))
return one;
if (decNumberIsNaN (&dn_x))
return x+x;
decNumberAbs (&dn_absx, &dn_x, &context);
FUNC_CONVERT_FROM_DN (&dn_absx, &absx, &context);
if(absx<one)
abs_x_vs_1 = -1;
else if (absx==one)
abs_x_vs_1 = 0;
else
abs_x_vs_1 = 1;
/* abs_x_vs_1 = decCompare(&dn_absx, &dn_one); */
if(abs_x_vs_1 == 0 && !decNumberIsNegative (&dn_x)) /* If x == +1 */
return one;
if (decNumberIsNaN (&dn_y))
return y+y;
/* Detect if y is odd/an integer */
decNumberToIntegralValue (&dn_temp, &dn_y, &context);
decNumberSubtract (&dn_temp2, &dn_temp, &dn_y, &context);
y_is_int = decNumberIsZero (&dn_temp2);
if (y_is_int)
{
FUNC_CONVERT_TO_DN (&two, &dn_two);
decNumberDivide (&dn_temp, &dn_y, &dn_two, &context);
decNumberToIntegralValue (&dn_temp2, &dn_temp, &context);
decNumberSubtract (&dn_temp3, &dn_temp2, &dn_temp, &context);
y_is_oddint = !decNumberIsZero (&dn_temp3);
}
/* Handle all special cases for which x = +-0 */
if (decNumberIsZero (&dn_x))
{
if(decNumberIsNegative (&dn_y))
{
if (decNumberIsInfinite (&dn_y)) /* +-0^-Inf = +Inf */
return -y;
/* Pole Error for x = +-0, y < 0 */
DFP_EXCEPT (FE_DIVBYZERO);
return decNumberIsNegative(&dn_x) && y_is_oddint ?
-DFP_HUGE_VAL : DFP_HUGE_VAL;
}
return decNumberIsNegative(&dn_x) && y_is_oddint ?
-DFP_CONSTANT(0.0) : DFP_CONSTANT(0.0);
}
/* Handle remaining special cases for x = +-Inf or y = +-Inf */
if (decNumberIsInfinite (&dn_x) || decNumberIsInfinite (&dn_y))
{
if (abs_x_vs_1 == 0) /* If (-1)^(+-Inf) */
return one;
if (abs_x_vs_1 < 0) /* x^(+-Inf), where 0<x<1 */
return decNumberIsNegative (&dn_y) ? DFP_HUGE_VAL
: DFP_CONSTANT(0.0);
if (decNumberIsNegative (&dn_y))
result = DFP_CONSTANT(0.0);
else
result = (DEC_TYPE)DEC_INFINITY;
if (y_is_oddint && decNumberIsNegative(&dn_x))
result = -result;
return result;
}
/* Domain Error: x < 0 && y is a finite non-int */
if (decNumberIsNegative (&dn_x) && !y_is_int)
{
DFP_EXCEPT (FE_INVALID);
return DFP_NAN;
}
decNumberPower (&dn_result, &dn_x, &dn_y, &context);
FUNC_CONVERT_FROM_DN (&dn_result, &result, &context);
if (context.status & DEC_Overflow)
DFP_EXCEPT (FE_OVERFLOW);
if (context.status & DEC_Underflow)
DFP_EXCEPT (FE_UNDERFLOW);
return result;
}
DecimalDecNumber power(const DecimalDecNumber &val, const DecimalDecNumber &exponent)
{
DecimalDecNumber result;
decNumberPower(&result.m_value, &val.m_value, &exponent.m_value, &val.m_context);
return result;
}
