diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-96/e_jnl.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-96/e_jnl.c | 137 |
1 files changed, 74 insertions, 63 deletions
diff --git a/sysdeps/ieee754/ldbl-96/e_jnl.c b/sysdeps/ieee754/ldbl-96/e_jnl.c index 11d097c271..95ff24201b 100644 --- a/sysdeps/ieee754/ldbl-96/e_jnl.c +++ b/sysdeps/ieee754/ldbl-96/e_jnl.c @@ -57,6 +57,7 @@ */ #include <errno.h> +#include <float.h> #include <math.h> #include <math_private.h> @@ -293,7 +294,7 @@ __ieee754_ynl (int n, long double x) u_int32_t se, i0, i1; int32_t i, ix; int32_t sign; - long double a, b, temp; + long double a, b, temp, ret; GET_LDOUBLE_WORDS (se, i0, i1, x); @@ -314,69 +315,79 @@ __ieee754_ynl (int n, long double x) } if (n == 0) return (__ieee754_y0l (x)); - if (n == 1) - return (sign * __ieee754_y1l (x)); - if (__glibc_unlikely (ix == 0x7fff)) - return zero; - if (ix >= 0x412D) - { /* x > 2**302 */ + { + SET_RESTORE_ROUNDL (FE_TONEAREST); + if (n == 1) + { + ret = sign * __ieee754_y1l (x); + goto out; + } + if (__glibc_unlikely (ix == 0x7fff)) + return zero; + if (ix >= 0x412D) + { /* x > 2**302 */ - /* ??? See comment above on the possible futility of this. */ + /* ??? See comment above on the possible futility of this. */ - /* (x >> n**2) - * Jn(x) = cos(x-(2n+1)*pi/4)*sqrt(2/x*pi) - * Yn(x) = sin(x-(2n+1)*pi/4)*sqrt(2/x*pi) - * Let s=sin(x), c=cos(x), - * xn=x-(2n+1)*pi/4, sqt2 = sqrt(2),then - * - * n sin(xn)*sqt2 cos(xn)*sqt2 - * ---------------------------------- - * 0 s-c c+s - * 1 -s-c -c+s - * 2 -s+c -c-s - * 3 s+c c-s - */ - long double s; - long double c; - __sincosl (x, &s, &c); - switch (n & 3) - { - case 0: - temp = s - c; - break; - case 1: - temp = -s - c; - break; - case 2: - temp = -s + c; - break; - case 3: - temp = s + c; - break; - } - b = invsqrtpi * temp / __ieee754_sqrtl (x); - } - else - { - a = __ieee754_y0l (x); - b = __ieee754_y1l (x); - /* quit if b is -inf */ - GET_LDOUBLE_WORDS (se, i0, i1, b); - /* Use 0xffffffff since GET_LDOUBLE_WORDS sign-extends SE. */ - for (i = 1; i < n && se != 0xffffffff; i++) - { - temp = b; - b = ((long double) (i + i) / x) * b - a; - GET_LDOUBLE_WORDS (se, i0, i1, b); - a = temp; - } - } - /* If B is +-Inf, set up errno accordingly. */ - if (! __finitel (b)) - __set_errno (ERANGE); - if (sign > 0) - return b; - else - return -b; + /* (x >> n**2) + * Jn(x) = cos(x-(2n+1)*pi/4)*sqrt(2/x*pi) + * Yn(x) = sin(x-(2n+1)*pi/4)*sqrt(2/x*pi) + * Let s=sin(x), c=cos(x), + * xn=x-(2n+1)*pi/4, sqt2 = sqrt(2),then + * + * n sin(xn)*sqt2 cos(xn)*sqt2 + * ---------------------------------- + * 0 s-c c+s + * 1 -s-c -c+s + * 2 -s+c -c-s + * 3 s+c c-s + */ + long double s; + long double c; + __sincosl (x, &s, &c); + switch (n & 3) + { + case 0: + temp = s - c; + break; + case 1: + temp = -s - c; + break; + case 2: + temp = -s + c; + break; + case 3: + temp = s + c; + break; + } + b = invsqrtpi * temp / __ieee754_sqrtl (x); + } + else + { + a = __ieee754_y0l (x); + b = __ieee754_y1l (x); + /* quit if b is -inf */ + GET_LDOUBLE_WORDS (se, i0, i1, b); + /* Use 0xffffffff since GET_LDOUBLE_WORDS sign-extends SE. */ + for (i = 1; i < n && se != 0xffffffff; i++) + { + temp = b; + b = ((long double) (i + i) / x) * b - a; + GET_LDOUBLE_WORDS (se, i0, i1, b); + a = temp; + } + } + /* If B is +-Inf, set up errno accordingly. */ + if (! __finitel (b)) + __set_errno (ERANGE); + if (sign > 0) + ret = b; + else + ret = -b; + } + out: + if (__isinfl (ret)) + ret = __copysignl (LDBL_MAX, ret) * LDBL_MAX; + return ret; } strong_alias (__ieee754_ynl, __ynl_finite) |