fix rand pseudo-random number generator

Fixed more documentation and code comments that referred to the old
additive 55 (a55) shuffle pseudo-random number generator.  We have
been using the subtractive 100 shuffle pseudo-random number generator
in place of the additive 55 generator for a while now.

cal/README

@@ -1130,7 +1130,7 @@ randbitrun.cal
     the number and length of identical bits runs match what is expected.
     By default, run_cnt is to test the next 65536 random values.
 
-    This tests the a55 generator.
+    This tests the subtractive 100 shuffle pseudo-random number generator.
 
 
 randmprime.cal
@@ -1177,7 +1177,7 @@ randrun.cal
     64 bit values.  By default, run_cnt is to test the next 65536
     random values.
 
-    This tests the a55 generator.
+    This tests the subtractive 100 shuffle pseudo-random number generator.
 
 repeat.cal
 

cal/randbitrun.cal

@@ -1,7 +1,7 @@
 /*
- * randbitrun - check rand bit run lengths of the a55 generator
+ * randbitrun - check rand bit run lengths of the subtractive 100 shuffle generator
  *
- * Copyright (C) 1999  Landon Curt Noll
+ * Copyright (C) 1999,2023  Landon Curt Noll
  *
  * Calc is open software; you can redistribute it and/or modify it under
  * the terms of the version 2.1 of the GNU Lesser General Public License

cal/regress.cal

@@ -1737,7 +1737,7 @@ print '024: parsed test_list()';
 /*
  * test 025: define test_rand for test 15dd
  *
- * This function tests the a55 shuffle pseudo-random number generator.
+ * This function tests the subtractive 100 shuffle pseudo-random number generator.
  */
 define test_rand()
 {
@@ -3547,6 +3547,12 @@ define test_trig()
 	vrfy(tnum++ == 3407,	'3407: tnum == 3407');
 	pi = pi(1e-20);
 
+	/* test trigonometric sine */
+	vrfy(sin(0, 1e-10) == 0,
+				strcat(str(tnum++), ': sin(0, 1e-10) == 0'));
+	vrfy(sin(pi/6, 1e-10) == 0.5,
+				strcat(str(tnum++), ': sin(pi/6, 1e-10) == 0.5'));
+
 	/* test versed trigonometric sine */
 	vrfy(versin(0, 1e-10) == 0,
 				strcat(str(tnum++), ': versin(0, 1e-10) == 0'));
@@ -8297,7 +8303,7 @@ return test_list();
 
 
 /*
- * test 15dd: test the a55 shuffle pseudo-random number generator
+ * test 15dd: test the subtractive 100 shuffle pseudo-random number generator
  */
 print;
 return test_rand();