libm/math: Make yx functions set errno=ERANGE for x=0

The y0, y1 and yn functions need separate conditions when x is zero as
that returns ERANGE instead of EDOM.

Also stop adjusting the return value from the __ieee754_y* functions
as that is already correct and we were just breaking it.

Signed-off-by: Keith Packard <keithp@keithp.com>

newlib/libm/math/w_j0.c

@@ -128,17 +128,19 @@ None of the Bessel functions are in ANSI C.
 	double z;
 	z = __ieee754_y0(x);
 	if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z;
-        if(x <= 0.0){
+        if(x < 0.0){
-	    /* y0(0) = -inf or y0(x<0) = NaN */
+	    /* y0(x<0) = NaN */
 	    errno = EDOM;
-	    return -HUGE_VAL;
+        }
+        if(x == 0.0){
+	    /* y0(0) = -inf */
+	    errno = ERANGE;
         }
 	if(x>X_TLOSS) {
 	    /* y0(x>X_TLOSS) */
 	    errno = ERANGE;
-	    return 0.0;
+	}
-	} else
+	return z;
-	    return z;
 #endif
 }
 

newlib/libm/math/w_j1.c

@@ -55,17 +55,19 @@
 	double z;
 	z = __ieee754_y1(x);
 	if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z;
-        if(x <= 0.0){
+        if(x < 0.0){
-	    /* y1(0) = -inf  or y1(x<0) = NaN */
+	    /* y1(x<0) = NaN */
 	    errno = EDOM;
-	    return -HUGE_VAL;
+        }
+        if(x == 0.0){
+	    /* y1(0) = -inf */
+	    errno = ERANGE;
         }
 	if(x>X_TLOSS) {
 	    /* y1(x>X_TLOSS) */
 	    errno = ERANGE;
-	    return 0.0;
+	}
-	} else
+	return z;
-	    return z;
 #endif
 }
 

newlib/libm/math/w_jn.c

@@ -77,17 +77,19 @@
 	double z;
 	z = __ieee754_yn(n,x);
 	if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z;
-        if(x <= 0.0){
+        if(x < 0.0){
-	    /* yn(n,0) = -inf or yn(x<0) = NaN */
+	    /* yn(x<0) = NaN */
 	    errno = EDOM;
-	    return -HUGE_VAL;
+        }
+        if(x == 0.0){
+	    /* yn(0) = -inf */
+	    errno = ERANGE;
         }
 	if(x>X_TLOSS) {
 	    /* yn(x>X_TLOSS) */
 	    errno = ERANGE;
-	    return 0.0;
+	}
-	} else
+	return z;
-	    return z;
 #endif
 }
 

newlib/libm/math/wf_j0.c

@@ -35,9 +35,8 @@
 	if(fabsf(x)>(float)X_TLOSS) {
 	    /* j0f(|x|>X_TLOSS) */
 	    errno = ERANGE;
-	    return 0.0f;
+	}
-	} else
+	return z;
-	    return z;
 #endif
 }
 
@@ -54,17 +53,19 @@
 	float z;
 	z = __ieee754_y0f(x);
 	if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z;
-        if(x <= (float)0.0){
+        if(x < 0.0f){
-	    /* y0f(0) = -inf  or y0f(x<0) = NaN */
+	    /* y0f(x<0) = NaN */
 	    errno = EDOM;
-	    return -HUGE_VALF;
         }
+	if (x == 0.0f){
+	    /* y0f(n,0) = -inf */
+	    errno = ERANGE;
+	}
 	if(x>(float)X_TLOSS) {
 	    /* y0f(x>X_TLOSS) */
 	    errno = ERANGE;
-	    return 0.0f;
+	}
-	} else
+	return z;
-	    return z;
 #endif
 }
 

newlib/libm/math/wf_j1.c

@@ -56,17 +56,19 @@
 	float z;
 	z = __ieee754_y1f(x);
 	if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z;
-        if(x <= 0.0f){
+        if(x < 0.0f){
-	    /* y1f(0) = -inf or y1f(x<0) = NaN */
+	    /* y1f(x<0) = NaN */
 	    errno = EDOM;
-	    return -HUGE_VALF;
         }
+	if (x == 0.0f){
+	    /* y1f(n,0) = -inf */
+	    errno = ERANGE;
+	}
 	if(x>(float)X_TLOSS) {
 	    /* y1f(x>X_TLOSS) */
 	    errno = ERANGE;
-	    return 0.0f;
+	}
-	} else
+	return z;
-	    return z;
 #endif
 }
 

newlib/libm/math/wf_jn.c

@@ -33,9 +33,8 @@
 	if(fabsf(x)>(float)X_TLOSS) {
 	    /* jnf(|x|>X_TLOSS) */
 	    errno = ERANGE;
-	    return 0.0f;
+	}
-	} else
+	return z;
-	    return z;
 #endif
 }
 
@@ -52,17 +51,19 @@
 	float z;
 	z = __ieee754_ynf(n,x);
 	if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z;
-        if(x <= 0.0f){
+        if(x < 0.0f){
-	    /* ynf(n,0) = -inf or ynf(x<0) = NaN */
+	    /* ynf(x<0) = NaN */
 	    errno = EDOM;
-	    return -HUGE_VALF;
         }
+	if (x == 0.0f){
+	    /* ynf(n,0) = -inf */
+	    errno = ERANGE;
+	}
 	if(x>(float)X_TLOSS) {
 	    /* ynf(x>X_TLOSS) */
 	    errno = ERANGE;
-	    return 0.0f;
+	}
-	} else
+	return z;
-	    return z;
 #endif
 }