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libs: workaround for Visual Studio(MSVC) Compiler Error C2124

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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 <anchao@xiaomi.com>
This commit is contained in:
chao an 2023-02-08 16:15:56 +08:00 committed by Xiang Xiao
parent 86aed87487
commit 634baa5a2f
2 changed files with 32 additions and 16 deletions
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18
include/nuttx/lib/math.h
View File

@ -74,15 +74,19 @@
/* General Constants ********************************************************/ /* General Constants ********************************************************/
#define INFINITY (1.0/0.0) #ifndef _HUGE_ENUF
#define NAN (0.0/0.0) # define _HUGE_ENUF (1e+300) /* _HUGE_ENUF*_HUGE_ENUF must overflow */
#define HUGE_VAL INFINITY #endif
#define INFINITY_F (1.0F/0.0F) #define INFINITY ((double)(_HUGE_ENUF * _HUGE_ENUF))
#define NAN_F (0.0F/0.0F) #define NAN ((double)(INFINITY * 0.0F))
#define HUGE_VAL INFINITY
#define INFINITY_L (1.0L/0.0L) #define INFINITY_F ((float)INFINITY)
#define NAN_L (0.0L/0.0L) #define NAN_F ((float)(INFINITY * 0.0F))
#define INFINITY_L ((long double)INFINITY)
#define NAN_L ((long double)(INFINITY * 0.0F))
#define isnan(x) ((x) != (x)) #define isnan(x) ((x) != (x))
#define isnanf(x) ((x) != (x)) #define isnanf(x) ((x) != (x))

30
libs/libc/math/lib_gamma.c
View File

@ -32,9 +32,12 @@
* *
****************************************************************************/ ****************************************************************************/
/* "A Precision Approximation of the Gamma Function" - Cornelius Lanczos (1964) /* "A Precision Approximation of the Gamma Function"
* "Lanczos Implementation of the Gamma Function" - Paul Godfrey (2001) * - Cornelius Lanczos (1964)
* "An Analysis of the Lanczos Gamma Approximation" - Glendon Ralph Pugh (2004) * "Lanczos Implementation of the Gamma Function"
* - Paul Godfrey (2001)
* "An Analysis of the Lanczos Gamma Approximation"
* - Glendon Ralph Pugh (2004)
* *
* Approximation method: * Approximation method:
* *
@ -133,9 +136,10 @@ static const double g_sden[N + 1] =
static const double g_fact[] = static const double g_fact[] =
{ {
1, 1, 2, 6, 24, 120, 720, 5040.0, 40320.0, 362880.0, 3628800.0, 39916800.0, 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, 479001600.0, 6227020800.0, 87178291200.0, 1307674368000.0,
355687428096000.0, 6402373705728000.0, 121645100408832000.0, 20922789888000.0, 355687428096000.0, 6402373705728000.0,
2432902008176640000.0, 51090942171709440000.0, 1124000727777607680000.0, 121645100408832000.0, 2432902008176640000.0, 51090942171709440000.0,
1124000727777607680000.0,
}; };
/* S(x) rational function for positive x */ /* S(x) rational function for positive x */
@ -151,6 +155,7 @@ static double sinpi(double x)
int n; int n;
/* argument reduction: x = |x| mod 2 */ /* argument reduction: x = |x| mod 2 */
/* spurious inexact when x is odd int */ /* spurious inexact when x is odd int */
x = x * 0.5; 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; double f;
uint64_t i; uint64_t i;
} u; } u;
u.f = x; u.f = x;
double absx; double absx;
@ -241,17 +247,19 @@ double tgamma(double x)
if (ix < (0x3ff - 54) << 20) if (ix < (0x3ff - 54) << 20)
{ {
/* |x| < 2^-54: tgamma(x) ~ 1/x, +-0 raises div-by-zero */ /* |x| < 2^-54: tgamma(x) ~ 1/x, +-0 raises div-by-zero */
return 1 / x; return 1 / x;
} }
/* integer arguments */ /* integer arguments */
/* raise inexact when non-integer */ /* raise inexact when non-integer */
if (x == floor(x)) if (x == floor(x))
{ {
if (sign) if (sign)
{ {
return 0 / 0.0; return NAN;
} }
if (x <= sizeof g_fact / sizeof *g_fact) if (x <= sizeof g_fact / sizeof *g_fact)
@ -261,6 +269,7 @@ double tgamma(double x)
} }
/* x >= 172: tgamma(x)=inf with overflow */ /* x >= 172: tgamma(x)=inf with overflow */
/* x =< -184: tgamma(x)=+-0 with underflow */ /* x =< -184: tgamma(x)=+-0 with underflow */
if (ix >= 0x40670000) if (ix >= 0x40670000)
@ -269,11 +278,13 @@ double tgamma(double x)
if (sign) 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)) if (floor(x) * 0.5 == floor(x * 0.5))
{ {
return 0; return 0;
} }
return -0.0; return -0.0;
} }
@ -302,6 +313,7 @@ double tgamma(double x)
if (x < 0) if (x < 0)
{ {
/* reflection formula for negative x */ /* reflection formula for negative x */
/* sinpi(absx) is not 0, integers are already handled */ /* sinpi(absx) is not 0, integers are already handled */
r = -pi / (sinpi(absx) * absx * r); r = -pi / (sinpi(absx) * absx * r);