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Remove more redundant computations in s_sin.c

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Removed more redundant computations in the slow paths of the sin and
cos functions.  The notable change is the passing of the most
significant bits of X to the slow functions to check if X is positive
so that just the absolute value of x can be passed and the repeated
ABS() operation is avoided.
This commit is contained in:
Siddhesh Poyarekar
2013-12-20 15:58:19 +05:30
parent 975195e466
commit 84ba214c21
2 changed files with 40 additions and 42 deletions
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7
ChangeLog
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@@ -1,5 +1,12 @@
2013-12-20 Siddhesh Poyarekar <siddhesh@redhat.com> 2013-12-20 Siddhesh Poyarekar <siddhesh@redhat.com>
* sysdeps/ieee754/dbl-64/s_sin.c (sloww1): Add new argument M.
Use M to change sign of result instead of X. Assume X is
positive.
(csloww1): Likewise.
(__sin): Adjust.
(__cos): Adjust.
* sysdeps/ieee754/dbl-64/s_sin.c (reduce_and_compute): Remove * sysdeps/ieee754/dbl-64/s_sin.c (reduce_and_compute): Remove
arguments A and DA. arguments A and DA.
(__sin): Adjust. (__sin): Adjust.

75
sysdeps/ieee754/dbl-64/s_sin.c
View File

@@ -134,7 +134,7 @@ static double slow (double x);
static double slow1 (double x); static double slow1 (double x);
static double slow2 (double x); static double slow2 (double x);
static double sloww (double x, double dx, double orig); static double sloww (double x, double dx, double orig);
static double sloww1 (double x, double dx, double orig); static double sloww1 (double x, double dx, double orig, int m);
static double sloww2 (double x, double dx, double orig, int n); static double sloww2 (double x, double dx, double orig, int n);
static double bsloww (double x, double dx, double orig, int n); static double bsloww (double x, double dx, double orig, int n);
static double bsloww1 (double x, double dx, double orig, int n); static double bsloww1 (double x, double dx, double orig, int n);
@@ -142,7 +142,7 @@ static double bsloww2 (double x, double dx, double orig, int n);
int __branred (double x, double *a, double *aa); int __branred (double x, double *a, double *aa);
static double cslow2 (double x); static double cslow2 (double x);
static double csloww (double x, double dx, double orig); static double csloww (double x, double dx, double orig);
static double csloww1 (double x, double dx, double orig); static double csloww1 (double x, double dx, double orig, int m);
static double csloww2 (double x, double dx, double orig, int n); static double csloww2 (double x, double dx, double orig, int n);
/* Reduce range of X and compute sin of a + da. K is the amount by which to /* Reduce range of X and compute sin of a + da. K is the amount by which to
@@ -287,18 +287,15 @@ __sin (double x)
else else
{ {
if (a > 0) if (a > 0)
{ m = 1;
m = 1;
t = a;
}
else else
{ {
m = 0; m = 0;
t = -a; a = -a;
da = -da; da = -da;
} }
u.x = big + t; u.x = big + a;
y = t - (u.x - big); y = a - (u.x - big);
xx = y * y; xx = y * y;
s = y + (da + y * xx * (sn3 + xx * sn5)); s = y + (da + y * xx * (sn3 + xx * sn5));
c = y * da + xx * (cs2 + xx * (cs4 + xx * cs6)); c = y * da + xx * (cs2 + xx * (cs4 + xx * cs6));
@@ -308,7 +305,7 @@ __sin (double x)
cor = (sn - res) + cor; cor = (sn - res) + cor;
cor = (cor > 0) ? 1.035 * cor + eps : 1.035 * cor - eps; cor = (cor > 0) ? 1.035 * cor + eps : 1.035 * cor - eps;
retval = ((res == res + cor) ? ((m) ? res : -res) retval = ((res == res + cor) ? ((m) ? res : -res)
: sloww1 (a, da, x)); : sloww1 (a, da, x, m));
} }
break; break;
@@ -375,17 +372,16 @@ __sin (double x)
if (a > 0) if (a > 0)
{ {
m = 1; m = 1;
t = a;
db = da; db = da;
} }
else else
{ {
m = 0; m = 0;
t = -a; a = -a;
db = -da; db = -da;
} }
u.x = big + t; u.x = big + a;
y = t - (u.x - big); y = a - (u.x - big);
xx = y * y; xx = y * y;
s = y + (db + y * xx * (sn3 + xx * sn5)); s = y + (db + y * xx * (sn3 + xx * sn5));
c = y * db + xx * (cs2 + xx * (cs4 + xx * cs6)); c = y * db + xx * (cs2 + xx * (cs4 + xx * cs6));
@@ -496,16 +492,15 @@ __cos (double x)
if (a > 0) if (a > 0)
{ {
m = 1; m = 1;
t = a;
} }
else else
{ {
m = 0; m = 0;
t = -a; a = -a;
da = -da; da = -da;
} }
u.x = big + t; u.x = big + a;
y = t - (u.x - big); y = a - (u.x - big);
xx = y * y; xx = y * y;
s = y + (da + y * xx * (sn3 + xx * sn5)); s = y + (da + y * xx * (sn3 + xx * sn5));
c = y * da + xx * (cs2 + xx * (cs4 + xx * cs6)); c = y * da + xx * (cs2 + xx * (cs4 + xx * cs6));
@@ -515,7 +510,7 @@ __cos (double x)
cor = (sn - res) + cor; cor = (sn - res) + cor;
cor = (cor > 0) ? 1.035 * cor + 1.0e-31 : 1.035 * cor - 1.0e-31; cor = (cor > 0) ? 1.035 * cor + 1.0e-31 : 1.035 * cor - 1.0e-31;
retval = ((res == res + cor) ? ((m) ? res : -res) retval = ((res == res + cor) ? ((m) ? res : -res)
: csloww1 (a, da, x)); : csloww1 (a, da, x, m));
} }
} /* else if (k < 0x400368fd) */ } /* else if (k < 0x400368fd) */
@@ -554,16 +549,15 @@ __cos (double x)
if (a > 0) if (a > 0)
{ {
m = 1; m = 1;
t = a;
} }
else else
{ {
m = 0; m = 0;
t = -a; a = -a;
da = -da; da = -da;
} }
u.x = big + t; u.x = big + a;
y = t - (u.x - big); y = a - (u.x - big);
xx = y * y; xx = y * y;
s = y + (da + y * xx * (sn3 + xx * sn5)); s = y + (da + y * xx * (sn3 + xx * sn5));
c = y * da + xx * (cs2 + xx * (cs4 + xx * cs6)); c = y * da + xx * (cs2 + xx * (cs4 + xx * cs6));
@@ -573,7 +567,7 @@ __cos (double x)
cor = (sn - res) + cor; cor = (sn - res) + cor;
cor = (cor > 0) ? 1.035 * cor + eps : 1.035 * cor - eps; cor = (cor > 0) ? 1.035 * cor + eps : 1.035 * cor - eps;
retval = ((res == res + cor) ? ((m) ? res : -res) retval = ((res == res + cor) ? ((m) ? res : -res)
: csloww1 (a, da, x)); : csloww1 (a, da, x, m));
} }
break; break;
@@ -638,17 +632,16 @@ __cos (double x)
if (a > 0) if (a > 0)
{ {
m = 1; m = 1;
t = a;
db = da; db = da;
} }
else else
{ {
m = 0; m = 0;
t = -a; a = -a;
db = -da; db = -da;
} }
u.x = big + t; u.x = big + a;
y = t - (u.x - big); y = a - (u.x - big);
xx = y * y; xx = y * y;
s = y + (db + y * xx * (sn3 + xx * sn5)); s = y + (db + y * xx * (sn3 + xx * sn5));
c = y * db + xx * (cs2 + xx * (cs4 + xx * cs6)); c = y * db + xx * (cs2 + xx * (cs4 + xx * cs6));
@@ -888,14 +881,13 @@ sloww (double x, double dx, double orig)
static double static double
SECTION SECTION
sloww1 (double x, double dx, double orig) sloww1 (double x, double dx, double orig, int m)
{ {
mynumber u; mynumber u;
double sn, ssn, cs, ccs, s, c, w[2], y, y1, y2, c1, c2, xx, cor, res; double sn, ssn, cs, ccs, s, c, w[2], y, y1, y2, c1, c2, xx, cor, res;
y = ABS (x); u.x = big + x;
u.x = big + y; y = x - (u.x - big);
y = y - (u.x - big);
xx = y * y; xx = y * y;
s = y * xx * (sn3 + xx * sn5); s = y * xx * (sn3 + xx * sn5);
c = xx * (cs2 + xx * (cs4 + xx * cs6)); c = xx * (cs2 + xx * (cs4 + xx * cs6));
@@ -916,10 +908,10 @@ sloww1 (double x, double dx, double orig)
cor = 1.0005 * cor - 3.1e-30 * ABS (orig); cor = 1.0005 * cor - 3.1e-30 * ABS (orig);
if (res == res + cor) if (res == res + cor)
return (x > 0) ? res : -res; return (m > 0) ? res : -res;
else else
{ {
__dubsin (ABS (x), dx, w); __dubsin (x, dx, w);
if (w[1] > 0) if (w[1] > 0)
cor = 1.000000005 * w[1] + 1.1e-30 * ABS (orig); cor = 1.000000005 * w[1] + 1.1e-30 * ABS (orig);
@@ -927,7 +919,7 @@ sloww1 (double x, double dx, double orig)
cor = 1.000000005 * w[1] - 1.1e-30 * ABS (orig); cor = 1.000000005 * w[1] - 1.1e-30 * ABS (orig);
if (w[0] == w[0] + cor) if (w[0] == w[0] + cor)
return (x > 0) ? w[0] : -w[0]; return (m > 0) ? w[0] : -w[0];
else else
return __mpsin (orig, 0, true); return __mpsin (orig, 0, true);
} }
@@ -1240,14 +1232,13 @@ csloww (double x, double dx, double orig)
static double static double
SECTION SECTION
csloww1 (double x, double dx, double orig) csloww1 (double x, double dx, double orig, int m)
{ {
mynumber u; mynumber u;
double sn, ssn, cs, ccs, s, c, w[2], y, y1, y2, c1, c2, xx, cor, res; double sn, ssn, cs, ccs, s, c, w[2], y, y1, y2, c1, c2, xx, cor, res;
y = ABS (x); u.x = big + x;
u.x = big + y; y = x - (u.x - big);
y = y - (u.x - big);
xx = y * y; xx = y * y;
s = y * xx * (sn3 + xx * sn5); s = y * xx * (sn3 + xx * sn5);
c = xx * (cs2 + xx * (cs4 + xx * cs6)); c = xx * (cs2 + xx * (cs4 + xx * cs6));
@@ -1268,16 +1259,16 @@ csloww1 (double x, double dx, double orig)
cor = 1.0005 * cor - 3.1e-30 * ABS (orig); cor = 1.0005 * cor - 3.1e-30 * ABS (orig);
if (res == res + cor) if (res == res + cor)
return (x > 0) ? res : -res; return (m > 0) ? res : -res;
else else
{ {
__dubsin (ABS (x), dx, w); __dubsin (x, dx, w);
if (w[1] > 0) if (w[1] > 0)
cor = 1.000000005 * w[1] + 1.1e-30 * ABS (orig); cor = 1.000000005 * w[1] + 1.1e-30 * ABS (orig);
else else
cor = 1.000000005 * w[1] - 1.1e-30 * ABS (orig); cor = 1.000000005 * w[1] - 1.1e-30 * ABS (orig);
if (w[0] == w[0] + cor) if (w[0] == w[0] + cor)
return (x > 0) ? w[0] : -w[0]; return (m > 0) ? w[0] : -w[0];
else else
return __mpcos (orig, 0, true); return __mpcos (orig, 0, true);
} }