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commit 634baa5a2f309812d8f2cc54511254f20d7a2aa7
Author: chao an <anc...@xiaomi.com>
AuthorDate: Wed Feb 8 16:15:56 2023 +0800
libs: workaround for Visual Studio(MSVC) Compiler Error C2124
D:\archer\code\nuttx\libs\libc\stdlib\lib_strtod.c: error C2124: divide or
mod by zero
Windows MSVC restrictions, MSVC doesn't allow division through a
zero literal, but allows it through const variable set to zero
Reference:
https://docs.microsoft.com/en-us/cpp/error-messages/compiler-errors-1/compiler-error-c2124?view=msvc-170
Signed-off-by: chao an <anc...@xiaomi.com>
---
include/nuttx/lib/math.h | 18 +++++++++++-------
libs/libc/math/lib_gamma.c | 30 +++++++++++++++++++++---------
2 files changed, 32 insertions(+), 16 deletions(-)
diff --git a/include/nuttx/lib/math.h b/include/nuttx/lib/math.h
index 3737c1715d..a5469c2e3f 100644
--- a/include/nuttx/lib/math.h
+++ b/include/nuttx/lib/math.h
@@ -74,15 +74,19 @@
/* General Constants ********************************************************/
-#define INFINITY (1.0/0.0)
-#define NAN (0.0/0.0)
-#define HUGE_VAL INFINITY
+#ifndef _HUGE_ENUF
+# define _HUGE_ENUF (1e+300) /* _HUGE_ENUF*_HUGE_ENUF must overflow */
+#endif
+
+#define INFINITY ((double)(_HUGE_ENUF * _HUGE_ENUF))
+#define NAN ((double)(INFINITY * 0.0F))
+#define HUGE_VAL INFINITY
-#define INFINITY_F (1.0F/0.0F)
-#define NAN_F (0.0F/0.0F)
+#define INFINITY_F ((float)INFINITY)
+#define NAN_F ((float)(INFINITY * 0.0F))
-#define INFINITY_L (1.0L/0.0L)
-#define NAN_L (0.0L/0.0L)
+#define INFINITY_L ((long double)INFINITY)
+#define NAN_L ((long double)(INFINITY * 0.0F))
#define isnan(x) ((x) != (x))
#define isnanf(x) ((x) != (x))
diff --git a/libs/libc/math/lib_gamma.c b/libs/libc/math/lib_gamma.c
index 60728e5c0e..a93c4629fb 100644
--- a/libs/libc/math/lib_gamma.c
+++ b/libs/libc/math/lib_gamma.c
@@ -32,9 +32,12 @@
*
****************************************************************************/
-/* "A Precision Approximation of the Gamma Function" - Cornelius Lanczos (1964)
- * "Lanczos Implementation of the Gamma Function" - Paul Godfrey (2001)
- * "An Analysis of the Lanczos Gamma Approximation" - Glendon Ralph Pugh (2004)
+/* "A Precision Approximation of the Gamma Function"
+ * - Cornelius Lanczos (1964)
+ * "Lanczos Implementation of the Gamma Function"
+ * - Paul Godfrey (2001)
+ * "An Analysis of the Lanczos Gamma Approximation"
+ * - Glendon Ralph Pugh (2004)
*
* Approximation method:
*
@@ -133,9 +136,10 @@ static const double g_sden[N + 1] =
static const double g_fact[] =
{
1, 1, 2, 6, 24, 120, 720, 5040.0, 40320.0, 362880.0, 3628800.0, 39916800.0,
- 479001600.0, 6227020800.0, 87178291200.0, 1307674368000.0, 20922789888000.0,
- 355687428096000.0, 6402373705728000.0, 121645100408832000.0,
- 2432902008176640000.0, 51090942171709440000.0, 1124000727777607680000.0,
+ 479001600.0, 6227020800.0, 87178291200.0, 1307674368000.0,
+ 20922789888000.0, 355687428096000.0, 6402373705728000.0,
+ 121645100408832000.0, 2432902008176640000.0, 51090942171709440000.0,
+ 1124000727777607680000.0,
};
/* S(x) rational function for positive x */
@@ -151,6 +155,7 @@ static double sinpi(double x)
int n;
/* argument reduction: x = |x| mod 2 */
+
/* spurious inexact when x is odd int */
x = x * 0.5;
@@ -205,7 +210,7 @@ static double s(double x)
}
}
- return num/den;
+ return num / den;
}
/****************************************************************************
@@ -219,6 +224,7 @@ double tgamma(double x)
double f;
uint64_t i;
} u;
+
u.f = x;
double absx;
@@ -241,17 +247,19 @@ double tgamma(double x)
if (ix < (0x3ff - 54) << 20)
{
/* |x| < 2^-54: tgamma(x) ~ 1/x, +-0 raises div-by-zero */
+
return 1 / x;
}
/* integer arguments */
+
/* raise inexact when non-integer */
if (x == floor(x))
{
if (sign)
{
- return 0 / 0.0;
+ return NAN;
}
if (x <= sizeof g_fact / sizeof *g_fact)
@@ -261,6 +269,7 @@ double tgamma(double x)
}
/* x >= 172: tgamma(x)=inf with overflow */
+
/* x =< -184: tgamma(x)=+-0 with underflow */
if (ix >= 0x40670000)
@@ -269,11 +278,13 @@ double tgamma(double x)
if (sign)
{
- FORCE_EVAL((float)(0x1p-126 / x));
+ FORCE_EVAL((float)(ldexp(1.0, -126) / x));
+
if (floor(x) * 0.5 == floor(x * 0.5))
{
return 0;
}
+
return -0.0;
}
@@ -302,6 +313,7 @@ double tgamma(double x)
if (x < 0)
{
/* reflection formula for negative x */
+
/* sinpi(absx) is not 0, integers are already handled */
r = -pi / (sinpi(absx) * absx * r);
