From f108799afa9b1d207e7139608c261f5546eb56bf Mon Sep 17 00:00:00 2001
From: Eric Andersen <andersen@codepoet.org>
Date: Tue, 2 Oct 2001 10:45:16 +0000
Subject: Add in some math lib tests

---
 test/math/epow.c | 215 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 215 insertions(+)
 create mode 100644 test/math/epow.c

(limited to 'test/math/epow.c')

diff --git a/test/math/epow.c b/test/math/epow.c
new file mode 100644
index 000000000..cc4994fe7
--- /dev/null
+++ b/test/math/epow.c
@@ -0,0 +1,215 @@
+/*						epow.c	*/
+/*  power function: z = x**y */
+/*  by Stephen L. Moshier. */
+
+
+#include "ehead.h"
+#define MAXPOS ((long) (((unsigned long) ~(0L)) >> 1))
+#define MAXNEG (-MAXPOS)
+/* #define MAXNEG (-MAXPOS - 1L) */
+
+extern int rndprc;
+void epowi();
+static void epowr();
+
+
+/* Run-time determination of largest integers */
+
+int powinited = 0;
+unsigned short maxposint[NE], maxnegint[NE];
+
+void initpow()
+{
+long li;
+
+li = MAXPOS;
+ltoe( &li, maxposint );
+li = MAXNEG;
+ltoe( &li, maxnegint );
+powinited = 1;
+}
+
+
+
+
+void epow( x, y, z )
+unsigned short *x, *y, *z;
+{
+unsigned short w[NE];
+int rndsav;
+long li;
+
+if( powinited == 0 )
+	initpow();
+
+/* Check for integer power. */
+
+efloor( y, w );
+if( (ecmp(y,w) == 0)
+   && (ecmp(maxposint,w) >= 0)
+   && (ecmp(w,maxnegint) >= 0) )
+	{
+	eifrac( y, &li, w );
+	epowi( x, y, z );
+	return;
+	}
+epowr( x, y, z );
+}
+
+
+
+
+/* y is integer valued. */
+
+void epowi( x, y, z )
+unsigned short x[], y[], z[];
+{
+unsigned short w[NE];
+long li, lx;
+unsigned long lu;
+int rndsav;
+unsigned short signx;
+/* unsigned short signy; */
+
+if( powinited == 0 )
+	initpow();
+
+rndsav = rndprc;
+
+if( (ecmp(y,maxposint) > 0) || (ecmp(maxnegint,y) > 0) )
+	{
+	epowr( x, y, z );
+	return;
+	}
+
+eifrac( y, &li, w );
+if( li < 0 )
+	lx = -li;
+else
+	lx = li;
+
+/*
+if( (x[NE-1] & (unsigned short )0x7fff) == 0 )
+*/
+
+if( ecmp( x, ezero) == 0 )
+	{
+	if( li == 0 )
+		{
+		emov( eone, z );
+		return;
+		}
+	else if( li < 0 )
+		{
+		einfin( z );
+		return;
+		}
+	else
+		{
+		eclear( z );
+		return;
+		}
+	}
+
+if( li == 0L )
+	{
+	emov( eone, z );
+	return;
+	}
+
+emov( x, w );
+signx = w[NE-1] & (unsigned short )0x8000;
+w[NE-1] &= (unsigned short )0x7fff;
+
+/* Overflow detection */
+/*
+lx = li * (w[NE-1] - 0x3fff);
+if( lx > 16385L )
+	{
+	einfin( z );
+	mtherr( "epowi", OVERFLOW );
+	goto done;
+	}
+if( lx < -16450L )
+	{
+	eclear( z );
+	return;
+	}
+*/
+rndprc = NBITS;
+
+if( li < 0 )
+	{
+	lu = (unsigned int )( -li );
+/*	signy = 0xffff;*/
+	ediv( w, eone, w );
+	}
+else
+	{
+	lu = (unsigned int )li;
+/*	signy = 0;*/
+	}
+
+/* First bit of the power */
+if( lu & 1 )
+	{
+	emov( w, z );
+	}	
+else
+	{
+	emov( eone, z );
+	signx = 0;
+	}
+
+
+lu >>= 1;
+while( lu != 0L )
+	{
+	emul( w, w, w );	/* arg to the 2-to-the-kth power */
+	if( lu & 1L )	/* if that bit is set, then include in product */
+		emul( w, z, z );
+	lu >>= 1;
+	}
+
+
+done:
+
+if( signx )
+	eneg( z ); /* odd power of negative number */
+
+/*
+if( signy )
+  	{
+  	if( ecmp( z, ezero ) != 0 )
+ 		{
+		ediv( z, eone, z );
+		}
+	else
+		{
+		einfin( z );
+		printf( "epowi OVERFLOW\n" );
+		}
+	}
+*/
+rndprc = rndsav;
+emul( eone, z, z );
+}
+
+
+
+/* z = exp( y * log(x) ) */
+
+static void epowr( x, y, z )
+unsigned short *x, *y, *z;
+{
+unsigned short w[NE];
+int rndsav;
+
+rndsav = rndprc;
+rndprc = NBITS;
+elog( x, w );
+emul( y, w, w );
+eexp( w, z );
+rndprc = rndsav;
+emul( eone, z, z );
+}
-- 
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