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main/emu_c99.cpp

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+#include "emu_c99.h"
+
+#include <cmath>
+#include <cfloat>
+
+#ifdef EMU_C99
+
+#if !defined(_MSC_VER) && !defined(_M_IX86) 
+#error Don't know how to implement C99 math functions here ...
+#else
+#if defined(_WIN64)
+#error Can't use inline assembler on Win 64 platform ...
+#endif
+#endif
+
+/* Floating point classification functions. */
+
+int __isinfd(double x)
+{
+    int c = _fpclass(x);
+    return c == _FPCLASS_NINF || c == _FPCLASS_PINF;
+}
+
+int __isnand(double x)
+{
+    int c = _fpclass(x);
+    return c == _FPCLASS_SNAN || c == _FPCLASS_QNAN;
+}
+
+int __isnormald(double x)
+{
+    int c = _fpclass(x);
+    return c == _FPCLASS_NN || c == _FPCLASS_PN;
+}
+
+/* Quoted from ISO 9899:1999 (E):
+
+7.12.9.5 The lrint and llrint functions
+
+    Synopsis
+
+1   #include <math.h>
+    long int lrint(double x);
+    long int lrintf(float x);
+    long int lrintl(long double x);
+    long long int llrint(double x);
+    long long int llrintf(float x);
+    long long int llrintl(long double x);
+
+    Description
+
+2   The lrint and llrint functions round their argument to the nearest 
+    integer value, rounding according to the current rounding direction. 
+    If the rounded value is outside the range of the return type, the 
+    numeric result is unspecified. A range error may occur if the magni-
+    tude of x is too large.
+
+    Returns
+
+3   The lrint and llrint functions return the rounded integer value.
+
+*/
+
+long int lrint(double x)
+{
+    long int i;
+
+    __asm {
+        fld   x
+        fistp i
+    }
+    return i;
+}
+
+/* Quoted from ISO 9899:1999 (E):
+
+    7.12.9.6 The round functions
+
+    Synopsis
+
+1   #include <math.h>
+    double round(double x);
+    float roundf(float x);
+    long double roundl(long double x);
+
+    Description
+
+2   The round functions round their argument to the nearest integer value in floating-point
+    format, rounding halfway cases away from zero, regardless of the current rounding
+    direction.
+
+    Returns
+
+3   The round functions return the rounded integer value.
+*/
+
+double round(double x)
+{
+    if (x >= 0.0)
+        return floor(x + 0.5);
+    else
+        return ceil(x - 0.5);
+}
+
+/* Quoted from ISO 9899:1999 (E):
+
+    7.12.10.2 The remainder functions
+
+    Synopsis
+
+1   #include <math.h>
+    double remainder(double x, double y);
+    float remainderf(float x, float y);
+    long double remainderl(long double x, long double y);
+
+    Description
+
+2   The remainder functions compute the remainder x REM y required 
+    by IEC 60559.201)
+
+    Returns
+
+3   The remainder functions return x REM y.
+
+Footnote:
+
+201) "When y != 0, the remainder r = x REM y is defined regardless of the 
+     rounding mode by the mathematical relation r = x - ny, where n is the 
+     integer nearest the exact value of x/y; whenever | n - x/y | = 1/2, 
+     then n is even. Thus, the remainder is always exact. If r = 0, its 
+     sign shall be that of x." This definition is applicable for all 
+     implementations.
+*/
+
+double remainder(double x, double y)
+{
+    double r;
+
+    __asm {
+            fld y
+            fld x
+    again:  fprem1           /* Partial IEEE 754 remainder of x/y. */
+            fstsw  ax        /* Move status word into AX. */
+            fwait            /* Wait till move completed. */
+            sahf             /* Move status word into CPU flags. */
+            jpe    again     /* Was partial if if C2=PF=1, repeat. */
+            fstp   st(1)     /* Move result to TOS. */
+            fstp   r         /* Store result and pop stack. */
+    }
+    return r;
+}
+
+
+#endif // EMU_C99