From f7953c44d545c91442f123300288853284501dab Mon Sep 17 00:00:00 2001 From: Siddhesh Poyarekar Date: Mon, 21 Dec 2015 10:41:46 +0530 Subject: Consolidate sin and cos code for 105414350 <|x|< 281474976710656 The sin and cos computation for this range of input is identical except for a difference in quadrants by 1. Exploit that fact and the common argument reduction to reduce computations for sincos. --- sysdeps/ieee754/dbl-64/s_sin.c | 253 ++++++++++++++++++----------------------- 1 file changed, 108 insertions(+), 145 deletions(-) (limited to 'sysdeps/ieee754/dbl-64/s_sin.c') diff --git a/sysdeps/ieee754/dbl-64/s_sin.c b/sysdeps/ieee754/dbl-64/s_sin.c index b619905..3b26a61 100644 --- a/sysdeps/ieee754/dbl-64/s_sin.c +++ b/sysdeps/ieee754/dbl-64/s_sin.c @@ -276,6 +276,104 @@ reduce_and_compute (double x, unsigned int k) return retval; } +static inline int4 +__always_inline +reduce_sincos_2 (double x, double *a, double *da) +{ + mynumber v; + + double t = (x * hpinv + toint); + double xn = t - toint; + v.x = t; + double xn1 = (xn + 8.0e22) - 8.0e22; + double xn2 = xn - xn1; + double y = ((((x - xn1 * mp1) - xn1 * mp2) - xn2 * mp1) - xn2 * mp2); + int4 n = v.i[LOW_HALF] & 3; + double db = xn1 * pp3; + t = y - db; + db = (y - t) - db; + db = (db - xn2 * pp3) - xn * pp4; + double b = t + db; + db = (t - b) + db; + + *a = b; + *da = db; + + return n; +} + +/* Compute sin (A + DA). cos can be computed by shifting the quadrant N + clockwise. */ +static double +__always_inline +do_sincos_2 (double a, double da, double x, int4 n, int4 k) +{ + double res, retval, cor, xx; + mynumber u; + + double eps = 1.0e-24; + + k = (n + k) & 3; + + switch (k) + { + case 2: + a = -a; + da = -da; + /* Fall through. */ + case 0: + xx = a * a; + if (xx < 0.01588) + { + /* Taylor series. */ + res = TAYLOR_SIN (xx, a, da, cor); + cor = (cor > 0) ? 1.02 * cor + eps : 1.02 * cor - eps; + retval = (res == res + cor) ? res : bsloww (a, da, x, n); + } + else + { + double t, db, y; + int m; + if (a > 0) + { + m = 1; + t = a; + db = da; + } + else + { + m = 0; + t = -a; + db = -da; + } + u.x = big + t; + y = t - (u.x - big); + res = do_sin (u, y, db, &cor); + cor = (cor > 0) ? 1.035 * cor + eps : 1.035 * cor - eps; + retval = ((res == res + cor) ? ((m) ? res : -res) + : bsloww1 (a, da, x, n)); + } + break; + + case 1: + case 3: + if (a < 0) + { + a = -a; + da = -da; + } + u.x = big + a; + double y = a - (u.x - big) + da; + res = do_cos (u, y, &cor); + cor = (cor > 0) ? 1.025 * cor + eps : 1.025 * cor - eps; + retval = ((res == res + cor) ? ((n & 2) ? -res : res) + : bsloww2 (a, da, x, n)); + break; + } + + return retval; +} + /*******************************************************************/ /* An ultimate sin routine. Given an IEEE double machine number x */ /* it computes the correctly rounded (to nearest) value of sin(x) */ @@ -288,8 +386,7 @@ SECTION #endif __sin (double x) { - double xx, res, t, cor, y, s, c, sn, ssn, cs, ccs, xn, a, da, db, eps, xn1, - xn2; + double xx, res, t, cor, y, s, c, sn, ssn, cs, ccs, xn, a, da, eps; mynumber u, v; int4 k, m, n; double retval = 0; @@ -421,83 +518,16 @@ __sin (double x) } } /* else if (k < 0x419921FB ) */ +#ifndef IN_SINCOS /*---------------------105414350 <|x|< 281474976710656 --------------------*/ else if (k < 0x42F00000) { - t = (x * hpinv + toint); - xn = t - toint; - v.x = t; - xn1 = (xn + 8.0e22) - 8.0e22; - xn2 = xn - xn1; - y = ((((x - xn1 * mp1) - xn1 * mp2) - xn2 * mp1) - xn2 * mp2); - n = v.i[LOW_HALF] & 3; - da = xn1 * pp3; - t = y - da; - da = (y - t) - da; - da = (da - xn2 * pp3) - xn * pp4; - a = t + da; - da = (t - a) + da; - eps = 1.0e-24; + double a, da; - switch (n) - { - case 0: - case 2: - xx = a * a; - if (n) - { - a = -a; - da = -da; - } - if (xx < 0.01588) - { - /* Taylor series. */ - res = TAYLOR_SIN (xx, a, da, cor); - cor = (cor > 0) ? 1.02 * cor + eps : 1.02 * cor - eps; - retval = (res == res + cor) ? res : bsloww (a, da, x, n); - } - else - { - double t; - if (a > 0) - { - m = 1; - t = a; - db = da; - } - else - { - m = 0; - t = -a; - db = -da; - } - u.x = big + t; - y = t - (u.x - big); - res = do_sin (u, y, db, &cor); - cor = (cor > 0) ? 1.035 * cor + eps : 1.035 * cor - eps; - retval = ((res == res + cor) ? ((m) ? res : -res) - : bsloww1 (a, da, x, n)); - } - break; - - case 1: - case 3: - if (a < 0) - { - a = -a; - da = -da; - } - u.x = big + a; - y = a - (u.x - big) + da; - res = do_cos (u, y, &cor); - cor = (cor > 0) ? 1.025 * cor + eps : 1.025 * cor - eps; - retval = ((res == res + cor) ? ((n & 2) ? -res : res) - : bsloww2 (a, da, x, n)); - break; - } + int4 n = reduce_sincos_2 (x, &a, &da); + retval = do_sincos_2 (a, da, x, n, 0); } /* else if (k < 0x42F00000 ) */ -#ifndef IN_SINCOS /* -----------------281474976710656 <|x| <2^1024----------------------------*/ else if (k < 0x7ff00000) retval = reduce_and_compute (x, 0); @@ -528,8 +558,7 @@ SECTION #endif __cos (double x) { - double y, xx, res, t, cor, xn, a, da, db, eps, xn1, - xn2; + double y, xx, res, t, cor, xn, a, da, eps; mynumber u, v; int4 k, m, n; @@ -657,81 +686,15 @@ __cos (double x) } } /* else if (k < 0x419921FB ) */ +#ifndef IN_SINCOS else if (k < 0x42F00000) { - t = (x * hpinv + toint); - xn = t - toint; - v.x = t; - xn1 = (xn + 8.0e22) - 8.0e22; - xn2 = xn - xn1; - y = ((((x - xn1 * mp1) - xn1 * mp2) - xn2 * mp1) - xn2 * mp2); - n = v.i[LOW_HALF] & 3; - da = xn1 * pp3; - t = y - da; - da = (y - t) - da; - da = (da - xn2 * pp3) - xn * pp4; - a = t + da; - da = (t - a) + da; - eps = 1.0e-24; - - switch (n) - { - case 1: - case 3: - xx = a * a; - if (n == 1) - { - a = -a; - da = -da; - } - if (xx < 0.01588) - { - res = TAYLOR_SIN (xx, a, da, cor); - cor = (cor > 0) ? 1.02 * cor + eps : 1.02 * cor - eps; - retval = (res == res + cor) ? res : bsloww (a, da, x, n); - } - else - { - double t; - if (a > 0) - { - m = 1; - t = a; - db = da; - } - else - { - m = 0; - t = -a; - db = -da; - } - u.x = big + t; - y = t - (u.x - big); - res = do_sin (u, y, db, &cor); - cor = (cor > 0) ? 1.035 * cor + eps : 1.035 * cor - eps; - retval = ((res == res + cor) ? ((m) ? res : -res) - : bsloww1 (a, da, x, n)); - } - break; + double a, da; - case 0: - case 2: - if (a < 0) - { - a = -a; - da = -da; - } - u.x = big + a; - y = a - (u.x - big) + da; - res = do_cos (u, y, &cor); - cor = (cor > 0) ? 1.025 * cor + eps : 1.025 * cor - eps; - retval = ((res == res + cor) ? ((n) ? -res : res) - : bsloww2 (a, da, x, n)); - break; - } + int4 n = reduce_sincos_2 (x, &a, &da); + retval = do_sincos_2 (a, da, x, n, 1); } /* else if (k < 0x42F00000 ) */ -#ifndef IN_SINCOS /* 281474976710656 <|x| <2^1024 */ else if (k < 0x7ff00000) retval = reduce_and_compute (x, 1); -- cgit v1.1