From 7f28c94eda576e3f972fc05468188986f2e45885 Mon Sep 17 00:00:00 2001
From: Torne Wuff <torne@wolfpuppy.org.uk>
Date: Sun, 17 Jan 2010 22:15:13 +0000
Subject: New plugin: frotz, a Z-machine interpreter, for playing interactive
 fiction.

The interpreter more or less passes all the tests in the z-machine test suite.
It should build for every target except Archos (for which it is disabled).


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24267 a1c6a512-1295-4272-9138-f99709370657
---
 apps/plugins/frotz/random.c | 82 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 apps/plugins/frotz/random.c

(limited to 'apps/plugins/frotz/random.c')

diff --git a/apps/plugins/frotz/random.c b/apps/plugins/frotz/random.c
new file mode 100644
index 0000000000..6ea14d89c9
--- /dev/null
+++ b/apps/plugins/frotz/random.c
@@ -0,0 +1,82 @@
+/* random.c - Z-machine random number generator
+ *	Copyright (c) 1995-1997 Stefan Jokisch
+ *
+ * This file is part of Frotz.
+ *
+ * Frotz is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Frotz is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include "frotz.h"
+
+static long A = 1;
+
+static int interval = 0;
+static int counter = 0;
+
+/*
+ * seed_random
+ *
+ * Set the seed value for the random number generator.
+ *
+ */
+
+void seed_random (int value)
+{
+
+    if (value == 0) {		/* ask interface for seed value */
+	A = os_random_seed ();
+	interval = 0;
+    } else if (value < 1000) {	/* special seed value */
+	counter = 0;
+	interval = value;
+    } else {			/* standard seed value */
+	A = value;
+	interval = 0;
+    }
+
+}/* seed_random */
+
+/*
+ * z_random, store a random number or set the random number seed.
+ *
+ *	zargs[0] = range (positive) or seed value (negative)
+ *
+ */
+
+void z_random ()
+{
+
+    if ((short) zargs[0] <= 0) {	/* set random seed */
+
+	seed_random (- (short) zargs[0]);
+	store (0);
+
+    } else {				/* generate random number */
+
+	zword result;
+
+	if (interval != 0) {		/* ...in special mode */
+	    result = counter++;
+	    if (counter == interval) counter = 0;
+	} else {			/* ...in standard mode */
+	    A = 0x015a4e35L * A + 1;
+	    result = (A >> 16) & 0x7fff;
+	}
+
+	store ((zword) (result % zargs[0] + 1));
+
+    }
+
+}/* z_random */
-- 
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