Libc-1272.250.1.tar.gz

[apple/libc.git] / gen / FreeBSD / rand48.h

diff --git a/gen/FreeBSD/rand48.h b/gen/FreeBSD/rand48.h
index 0a3d83d3c0c731561f762c8de8fc72b8d7ae9302..e799eba0f088246f3cf603eea55170745baf9552 100644 (file)
--- a/gen/FreeBSD/rand48.h
+++ b/gen/FreeBSD/rand48.h
@@ -19,8 +19,6 @@
 #include <math.h>
 #include <stdlib.h>
 
-void           _dorand48(unsigned short[3]);
-
 #define        RAND48_SEED_0   (0x330e)
 #define        RAND48_SEED_1   (0xabcd)
 #define        RAND48_SEED_2   (0x1234)
@@ -29,4 +27,55 @@ void         _dorand48(unsigned short[3]);
 #define        RAND48_MULT_2   (0x0005)
 #define        RAND48_ADD      (0x000b)
 
+typedef unsigned long long uint48;
+
+extern uint48 _rand48_seed;
+extern uint48 _rand48_mult;
+extern uint48 _rand48_add;
+
+#define TOUINT48(x,y,z) \
+       ((uint48)(x) + (((uint48)(y)) << 16) + (((uint48)(z)) << 32))
+
+#define RAND48_SEED    TOUINT48(RAND48_SEED_0, RAND48_SEED_1, RAND48_SEED_2)
+#define RAND48_MULT    TOUINT48(RAND48_MULT_0, RAND48_MULT_1, RAND48_MULT_2)
+
+#define LOADRAND48(l,x) \
+       (l) = TOUINT48((x)[0], (x)[1], (x)[2])
+
+#define STORERAND48(l,x) \
+       (x)[0] = (unsigned short)(l); \
+       (x)[1] = (unsigned short)((l) >> 16); \
+       (x)[2] = (unsigned short)((l) >> 32)
+
+#define _DORAND48(l) \
+       (l) = (l) * _rand48_mult + _rand48_add
+
+#define DORAND48(l,x) \
+       LOADRAND48(l, x); \
+       _DORAND48(l); \
+       STORERAND48(l, x)
+
+#include "fpmath.h"
+
+/*
+ * Optimization for speed: avoid int-to-double conversion.  Assume doubles
+ * are IEEE-754 and insert the bits directly.  To normalize, the (1 << 52)
+ * is the hidden bit, which the first set bit is shifted to.
+ */
+#define ERAND48_BEGIN \
+       union { \
+               union IEEEd2bits ieee; \
+               unsigned long long l; \
+       } u; \
+       int s
+
+#define ERAND48_END(x) \
+       u.l = ((x) & 0xffffffffffffULL); \
+       if (u.l == 0) \
+               return 0.0; \
+       u.l <<= 5; \
+       for(s = 0; !(u.l & (1LL << 52)); s++, u.l <<= 1) {} \
+       u.ieee.bits.exp = 1022 - s; \
+       return u.ieee.d
+
 #endif /* _RAND48_H_ */