Format s_atan.c

1 files changed, 246 insertions, 151 deletions

diff --git a/sysdeps/ieee754/dbl-64/s_atan.c b/sysdeps/ieee754/dbl-64/s_atan.c
index aa3564d560..dc1716f93a 100644
--- a/sysdeps/ieee754/dbl-64/s_atan.c
+++ b/sysdeps/ieee754/dbl-64/s_atan.c
@@ -43,177 +43,272 @@
 #include "atnat.h"
 #include <math.h>
 
-void __mpatan(mp_no *,mp_no *,int);          /* see definition in mpatan.c */
-static double atanMp(double,const int[]);
+void __mpatan (mp_no *, mp_no *, int);	/* see definition in mpatan.c */
+static double atanMp (double, const int[]);
 
   /* Fix the sign of y and return */
-static double  __signArctan(double x,double y){
-  return __copysign(y, x);
+static double
+__signArctan (double x, double y)
+{
+  return __copysign (y, x);
 }
 
 
 /* An ultimate atan() routine. Given an IEEE double machine number x,    */
 /* routine computes the correctly rounded (to nearest) value of atan(x). */
-double atan(double x) {
-
-
-  double cor,s1,ss1,s2,ss2,t1,t2,t3,t7,t8,t9,t10,u,u2,u3,
-	 v,vv,w,ww,y,yy,z,zz;
+double
+atan (double x)
+{
+  double cor, s1, ss1, s2, ss2, t1, t2, t3, t7, t8, t9, t10, u, u2, u3,
+    v, vv, w, ww, y, yy, z, zz;
 #ifndef DLA_FMS
-  double t4,t5,t6;
+  double t4, t5, t6;
 #endif
-  int i,ux,dx;
-  static const int pr[M]={6,8,10,32};
+  int i, ux, dx;
+  static const int pr[M] = { 6, 8, 10, 32 };
   number num;
 
-  num.d = x;  ux = num.i[HIGH_HALF];  dx = num.i[LOW_HALF];
+  num.d = x;
+  ux = num.i[HIGH_HALF];
+  dx = num.i[LOW_HALF];
 
   /* x=NaN */
-  if (((ux&0x7ff00000)==0x7ff00000) && (((ux&0x000fffff)|dx)!=0x00000000))
-    return x+x;
+  if (((ux & 0x7ff00000) == 0x7ff00000)
+      && (((ux & 0x000fffff) | dx) != 0x00000000))
+    return x + x;
 
   /* Regular values of x, including denormals +-0 and +-INF */
-  u = (x<ZERO) ? -x : x;
-  if (u<C) {
-    if (u<B) {
-      if (u<A) {                                           /* u < A */
-	 return x; }
-      else {                                               /* A <= u < B */
-	v=x*x;  yy=x*v*(d3.d+v*(d5.d+v*(d7.d+v*(d9.d+v*(d11.d+v*d13.d)))));
-	if ((y=x+(yy-U1*x)) == x+(yy+U1*x))  return y;
-
-	EMULV(x,x,v,vv,t1,t2,t3,t4,t5)                       /* v+vv=x^2 */
-	s1=v*(f11.d+v*(f13.d+v*(f15.d+v*(f17.d+v*f19.d))));
-	ADD2(f9.d,ff9.d,s1,ZERO,s2,ss2,t1,t2)
-	MUL2(v,vv,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-	ADD2(f7.d,ff7.d,s1,ss1,s2,ss2,t1,t2)
-	MUL2(v,vv,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-	ADD2(f5.d,ff5.d,s1,ss1,s2,ss2,t1,t2)
-	MUL2(v,vv,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-	ADD2(f3.d,ff3.d,s1,ss1,s2,ss2,t1,t2)
-	MUL2(v,vv,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-	MUL2(x,ZERO,s1,ss1,s2,ss2,t1,t2,t3,t4,t5,t6,t7,t8)
-	ADD2(x,ZERO,s2,ss2,s1,ss1,t1,t2)
-	if ((y=s1+(ss1-U5*s1)) == s1+(ss1+U5*s1))  return y;
-
-	return atanMp(x,pr);
-      } }
-    else {  /* B <= u < C */
-      i=(TWO52+TWO8*u)-TWO52;  i-=16;
-      z=u-cij[i][0].d;
-      yy=z*(cij[i][2].d+z*(cij[i][3].d+z*(cij[i][4].d+
-			z*(cij[i][5].d+z* cij[i][6].d))));
-      t1=cij[i][1].d;
-      if (i<112) {
-	if (i<48)  u2=U21;    /* u < 1/4        */
-	else       u2=U22; }  /* 1/4 <= u < 1/2 */
-      else {
-	if (i<176) u2=U23;    /* 1/2 <= u < 3/4 */
-	else       u2=U24; }  /* 3/4 <= u <= 1  */
-      if ((y=t1+(yy-u2*t1)) == t1+(yy+u2*t1))  return __signArctan(x,y);
-
-      z=u-hij[i][0].d;
-      s1=z*(hij[i][11].d+z*(hij[i][12].d+z*(hij[i][13].d+
-	 z*(hij[i][14].d+z* hij[i][15].d))));
-      ADD2(hij[i][9].d,hij[i][10].d,s1,ZERO,s2,ss2,t1,t2)
-      MUL2(z,ZERO,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-      ADD2(hij[i][7].d,hij[i][8].d,s1,ss1,s2,ss2,t1,t2)
-      MUL2(z,ZERO,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-      ADD2(hij[i][5].d,hij[i][6].d,s1,ss1,s2,ss2,t1,t2)
-      MUL2(z,ZERO,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-      ADD2(hij[i][3].d,hij[i][4].d,s1,ss1,s2,ss2,t1,t2)
-      MUL2(z,ZERO,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-      ADD2(hij[i][1].d,hij[i][2].d,s1,ss1,s2,ss2,t1,t2)
-      if ((y=s2+(ss2-U6*s2)) == s2+(ss2+U6*s2))  return __signArctan(x,y);
-
-      return atanMp(x,pr);
-    }
-  }
-  else {
-    if (u<D) { /* C <= u < D */
-      w=ONE/u;
-      EMULV(w,u,t1,t2,t3,t4,t5,t6,t7)
-      ww=w*((ONE-t1)-t2);
-      i=(TWO52+TWO8*w)-TWO52;  i-=16;
-      z=(w-cij[i][0].d)+ww;
-      yy=HPI1-z*(cij[i][2].d+z*(cij[i][3].d+z*(cij[i][4].d+
-			     z*(cij[i][5].d+z* cij[i][6].d))));
-      t1=HPI-cij[i][1].d;
-      if (i<112)  u3=U31;  /* w <  1/2 */
-      else        u3=U32;  /* w >= 1/2 */
-      if ((y=t1+(yy-u3)) == t1+(yy+u3))  return __signArctan(x,y);
-
-      DIV2(ONE,ZERO,u,ZERO,w,ww,t1,t2,t3,t4,t5,t6,t7,t8,t9,t10)
-      t1=w-hij[i][0].d;
-      EADD(t1,ww,z,zz)
-      s1=z*(hij[i][11].d+z*(hij[i][12].d+z*(hij[i][13].d+
-	 z*(hij[i][14].d+z* hij[i][15].d))));
-      ADD2(hij[i][9].d,hij[i][10].d,s1,ZERO,s2,ss2,t1,t2)
-      MUL2(z,zz,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-      ADD2(hij[i][7].d,hij[i][8].d,s1,ss1,s2,ss2,t1,t2)
-      MUL2(z,zz,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-      ADD2(hij[i][5].d,hij[i][6].d,s1,ss1,s2,ss2,t1,t2)
-      MUL2(z,zz,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-      ADD2(hij[i][3].d,hij[i][4].d,s1,ss1,s2,ss2,t1,t2)
-      MUL2(z,zz,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-      ADD2(hij[i][1].d,hij[i][2].d,s1,ss1,s2,ss2,t1,t2)
-      SUB2(HPI,HPI1,s2,ss2,s1,ss1,t1,t2)
-      if ((y=s1+(ss1-U7)) == s1+(ss1+U7))  return __signArctan(x,y);
-
-    return atanMp(x,pr);
-    }
-    else {
-      if (u<E) { /* D <= u < E */
-	w=ONE/u;   v=w*w;
-	EMULV(w,u,t1,t2,t3,t4,t5,t6,t7)
-	yy=w*v*(d3.d+v*(d5.d+v*(d7.d+v*(d9.d+v*(d11.d+v*d13.d)))));
-	ww=w*((ONE-t1)-t2);
-	ESUB(HPI,w,t3,cor)
-	yy=((HPI1+cor)-ww)-yy;
-	if ((y=t3+(yy-U4)) == t3+(yy+U4))  return __signArctan(x,y);
-
-	DIV2(ONE,ZERO,u,ZERO,w,ww,t1,t2,t3,t4,t5,t6,t7,t8,t9,t10)
-	MUL2(w,ww,w,ww,v,vv,t1,t2,t3,t4,t5,t6,t7,t8)
-	s1=v*(f11.d+v*(f13.d+v*(f15.d+v*(f17.d+v*f19.d))));
-	ADD2(f9.d,ff9.d,s1,ZERO,s2,ss2,t1,t2)
-	MUL2(v,vv,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-	ADD2(f7.d,ff7.d,s1,ss1,s2,ss2,t1,t2)
-	MUL2(v,vv,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-	ADD2(f5.d,ff5.d,s1,ss1,s2,ss2,t1,t2)
-	MUL2(v,vv,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-	ADD2(f3.d,ff3.d,s1,ss1,s2,ss2,t1,t2)
-	MUL2(v,vv,s2,ss2,s1,ss1,t1,t2,t3,t4,t5,t6,t7,t8)
-	MUL2(w,ww,s1,ss1,s2,ss2,t1,t2,t3,t4,t5,t6,t7,t8)
-	ADD2(w,ww,s2,ss2,s1,ss1,t1,t2)
-	SUB2(HPI,HPI1,s1,ss1,s2,ss2,t1,t2)
-	if ((y=s2+(ss2-U8)) == s2+(ss2+U8))  return __signArctan(x,y);
-
-      return atanMp(x,pr);
-      }
-      else {
-	/* u >= E */
-	if (x>0) return  HPI;
-	else     return MHPI; }
+  u = (x < ZERO) ? -x : x;
+  if (u < C)
+    {
+      if (u < B)
+	{
+	  if (u < A)
+	    return x;
+	  else
+	    {			/* A <= u < B */
+	      v = x * x;
+	      yy = d11.d + v * d13.d;
+	      yy = d9.d + v * yy;
+	      yy = d7.d + v * yy;
+	      yy = d5.d + v * yy;
+	      yy = d3.d + v * yy;
+	      yy *= x * v;
+
+	      if ((y = x + (yy - U1 * x)) == x + (yy + U1 * x))
+		return y;
+
+	      EMULV (x, x, v, vv, t1, t2, t3, t4, t5);	/* v+vv=x^2 */
+
+	      s1 = f17.d + v * f19.d;
+	      s1 = f15.d + v * s1;
+	      s1 = f13.d + v * s1;
+	      s1 = f11.d + v * s1;
+	      s1 *= v;
+
+	      ADD2 (f9.d, ff9.d, s1, ZERO, s2, ss2, t1, t2);
+	      MUL2 (v, vv, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	      ADD2 (f7.d, ff7.d, s1, ss1, s2, ss2, t1, t2);
+	      MUL2 (v, vv, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	      ADD2 (f5.d, ff5.d, s1, ss1, s2, ss2, t1, t2);
+	      MUL2 (v, vv, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	      ADD2 (f3.d, ff3.d, s1, ss1, s2, ss2, t1, t2);
+	      MUL2 (v, vv, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	      MUL2 (x, ZERO, s1, ss1, s2, ss2, t1, t2, t3, t4, t5, t6, t7,
+		    t8);
+	      ADD2 (x, ZERO, s2, ss2, s1, ss1, t1, t2);
+	      if ((y = s1 + (ss1 - U5 * s1)) == s1 + (ss1 + U5 * s1))
+		return y;
+
+	      return atanMp (x, pr);
+	    }
+	}
+      else
+	{			/* B <= u < C */
+	  i = (TWO52 + TWO8 * u) - TWO52;
+	  i -= 16;
+	  z = u - cij[i][0].d;
+	  yy = cij[i][5].d + z * cij[i][6].d;
+	  yy = cij[i][4].d + z * yy;
+	  yy = cij[i][3].d + z * yy;
+	  yy = cij[i][2].d + z * yy;
+	  yy *= z;
+
+	  t1 = cij[i][1].d;
+	  if (i < 112)
+	    {
+	      if (i < 48)
+		u2 = U21;	/* u < 1/4        */
+	      else
+		u2 = U22;
+	    }			/* 1/4 <= u < 1/2 */
+	  else
+	    {
+	      if (i < 176)
+		u2 = U23;	/* 1/2 <= u < 3/4 */
+	      else
+		u2 = U24;
+	    }			/* 3/4 <= u <= 1  */
+	  if ((y = t1 + (yy - u2 * t1)) == t1 + (yy + u2 * t1))
+	    return __signArctan (x, y);
+
+	  z = u - hij[i][0].d;
+
+	  s1 = hij[i][14].d + z * hij[i][15].d;
+	  s1 = hij[i][13].d + z * s1;
+	  s1 = hij[i][12].d + z * s1;
+	  s1 = hij[i][11].d + z * s1;
+	  s1 *= z;
+
+	  ADD2 (hij[i][9].d, hij[i][10].d, s1, ZERO, s2, ss2, t1, t2);
+	  MUL2 (z, ZERO, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	  ADD2 (hij[i][7].d, hij[i][8].d, s1, ss1, s2, ss2, t1, t2);
+	  MUL2 (z, ZERO, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	  ADD2 (hij[i][5].d, hij[i][6].d, s1, ss1, s2, ss2, t1, t2);
+	  MUL2 (z, ZERO, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	  ADD2 (hij[i][3].d, hij[i][4].d, s1, ss1, s2, ss2, t1, t2);
+	  MUL2 (z, ZERO, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	  ADD2 (hij[i][1].d, hij[i][2].d, s1, ss1, s2, ss2, t1, t2);
+	  if ((y = s2 + (ss2 - U6 * s2)) == s2 + (ss2 + U6 * s2))
+	    return __signArctan (x, y);
+
+	  return atanMp (x, pr);
+	}
     }
-  }
+  else
+    {
+      if (u < D)
+	{			/* C <= u < D */
+	  w = ONE / u;
+	  EMULV (w, u, t1, t2, t3, t4, t5, t6, t7);
+	  ww = w * ((ONE - t1) - t2);
+	  i = (TWO52 + TWO8 * w) - TWO52;
+	  i -= 16;
+	  z = (w - cij[i][0].d) + ww;
+
+	  yy = cij[i][5].d + z * cij[i][6].d;
+	  yy = cij[i][4].d + z * yy;
+	  yy = cij[i][3].d + z * yy;
+	  yy = cij[i][2].d + z * yy;
+	  yy  = HPI1 - z * yy;
 
+	  t1 = HPI - cij[i][1].d;
+	  if (i < 112)
+	    u3 = U31;		/* w <  1/2 */
+	  else
+	    u3 = U32;		/* w >= 1/2 */
+	  if ((y = t1 + (yy - u3)) == t1 + (yy + u3))
+	    return __signArctan (x, y);
+
+	  DIV2 (ONE, ZERO, u, ZERO, w, ww, t1, t2, t3, t4, t5, t6, t7, t8, t9,
+		t10);
+	  t1 = w - hij[i][0].d;
+	  EADD (t1, ww, z, zz);
+
+	  s1 = hij[i][14].d + z * hij[i][15].d;
+	  s1 = hij[i][13].d + z * s1;
+	  s1 = hij[i][12].d + z * s1;
+	  s1 = hij[i][11].d + z * s1;
+	  s1 *= z;
+
+	  ADD2 (hij[i][9].d, hij[i][10].d, s1, ZERO, s2, ss2, t1, t2);
+	  MUL2 (z, zz, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	  ADD2 (hij[i][7].d, hij[i][8].d, s1, ss1, s2, ss2, t1, t2);
+	  MUL2 (z, zz, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	  ADD2 (hij[i][5].d, hij[i][6].d, s1, ss1, s2, ss2, t1, t2);
+	  MUL2 (z, zz, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	  ADD2 (hij[i][3].d, hij[i][4].d, s1, ss1, s2, ss2, t1, t2);
+	  MUL2 (z, zz, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	  ADD2 (hij[i][1].d, hij[i][2].d, s1, ss1, s2, ss2, t1, t2);
+	  SUB2 (HPI, HPI1, s2, ss2, s1, ss1, t1, t2);
+	  if ((y = s1 + (ss1 - U7)) == s1 + (ss1 + U7))
+	    return __signArctan (x, y);
+
+	  return atanMp (x, pr);
+	}
+      else
+	{
+	  if (u < E)
+	    {			/* D <= u < E */
+	      w = ONE / u;
+	      v = w * w;
+	      EMULV (w, u, t1, t2, t3, t4, t5, t6, t7);
+
+	      yy = d11.d + v * d13.d;
+	      yy = d9.d + v * yy;
+	      yy = d7.d + v * yy;
+	      yy = d5.d + v * yy;
+	      yy = d3.d + v * yy;
+	      yy *= w * v;
+
+	      ww = w * ((ONE - t1) - t2);
+	      ESUB (HPI, w, t3, cor);
+	      yy = ((HPI1 + cor) - ww) - yy;
+	      if ((y = t3 + (yy - U4)) == t3 + (yy + U4))
+		return __signArctan (x, y);
+
+	      DIV2 (ONE, ZERO, u, ZERO, w, ww, t1, t2, t3, t4, t5, t6, t7, t8,
+		    t9, t10);
+	      MUL2 (w, ww, w, ww, v, vv, t1, t2, t3, t4, t5, t6, t7, t8);
+
+	      s1 = f17.d + v * f19.d;
+	      s1 = f15.d + v * s1;
+	      s1 = f13.d + v * s1;
+	      s1 = f11.d + v * s1;
+	      s1 *= v;
+
+	      ADD2 (f9.d, ff9.d, s1, ZERO, s2, ss2, t1, t2);
+	      MUL2 (v, vv, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	      ADD2 (f7.d, ff7.d, s1, ss1, s2, ss2, t1, t2);
+	      MUL2 (v, vv, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	      ADD2 (f5.d, ff5.d, s1, ss1, s2, ss2, t1, t2);
+	      MUL2 (v, vv, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	      ADD2 (f3.d, ff3.d, s1, ss1, s2, ss2, t1, t2);
+	      MUL2 (v, vv, s2, ss2, s1, ss1, t1, t2, t3, t4, t5, t6, t7, t8);
+	      MUL2 (w, ww, s1, ss1, s2, ss2, t1, t2, t3, t4, t5, t6, t7, t8);
+	      ADD2 (w, ww, s2, ss2, s1, ss1, t1, t2);
+	      SUB2 (HPI, HPI1, s1, ss1, s2, ss2, t1, t2);
+
+	      if ((y = s2 + (ss2 - U8)) == s2 + (ss2 + U8))
+		return __signArctan (x, y);
+
+	      return atanMp (x, pr);
+	    }
+	  else
+	    {
+	      /* u >= E */
+	      if (x > 0)
+		return HPI;
+	      else
+		return MHPI;
+	    }
+	}
+    }
 }
 
  /* Final stages. Compute atan(x) by multiple precision arithmetic */
-static double atanMp(double x,const int pr[]){
-  mp_no mpx,mpy,mpy2,mperr,mpt1,mpy1;
-  double y1,y2;
-  int i,p;
-
-for (i=0; i<M; i++) {
-    p = pr[i];
-    __dbl_mp(x,&mpx,p);          __mpatan(&mpx,&mpy,p);
-    __dbl_mp(u9[i].d,&mpt1,p);   __mul(&mpy,&mpt1,&mperr,p);
-    __add(&mpy,&mperr,&mpy1,p);  __sub(&mpy,&mperr,&mpy2,p);
-    __mp_dbl(&mpy1,&y1,p);       __mp_dbl(&mpy2,&y2,p);
-    if (y1==y2)   return y1;
-  }
-  return y1; /*if unpossible to do exact computing */
+static double
+atanMp (double x, const int pr[])
+{
+  mp_no mpx, mpy, mpy2, mperr, mpt1, mpy1;
+  double y1, y2;
+  int i, p;
+
+  for (i = 0; i < M; i++)
+    {
+      p = pr[i];
+      __dbl_mp (x, &mpx, p);
+      __mpatan (&mpx, &mpy, p);
+      __dbl_mp (u9[i].d, &mpt1, p);
+      __mul (&mpy, &mpt1, &mperr, p);
+      __add (&mpy, &mperr, &mpy1, p);
+      __sub (&mpy, &mperr, &mpy2, p);
+      __mp_dbl (&mpy1, &y1, p);
+      __mp_dbl (&mpy2, &y2, p);
+      if (y1 == y2)
+	return y1;
+    }
+  return y1;			/*if impossible to do exact computing */
 }
 
 #ifdef NO_LONG_DOUBLE