xref: /original-bsd/usr.bin/pascal/px/READ_ME (revision a1c2194a)
1/*-
2 * Copyright (c) 1980 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 *
7 *	@(#)READ_ME	5.2 (Berkeley) 04/16/91
8 */
9
10   This directory contains the source code for the Version 7 VAX
11interpreter for Pascal. Following standard convensions, the makefile
12contains four commands:
13
14	px - compile px
15
16	install - compile and install px in /usr/ucb
17
18	clean - clean out directory
19
20	print - print out a listing of px
21
22
23
24Bugs and Limitations:
25
26   Runtime error messages could give far more information than they
27currently do. (eg the actual value of a subscript which is out
28of range)
29
30   It should be possible to resume execution following many of
31the runtime errors. (eg fixed overflow, interrupt, etc)
32
33
34Comparison of Pascal with C compiler
35
36In an attempt to compare compiled versus interpreted execution speeds
37the 'Tower of Hanoi' benchmark (see hanoi.p, hanoi.c) was run with
38the following results:
39
40Data:
41	number of disks: 		   16
42	number of moves required:	65535
43
44Compiler, Flags		  Compile	Compile		 Run	 Run
45			   Time		 Factor		 Time	Factor
46Pi, full tests		 0.4u+0.4s	  1.0		42.7u	  1.0
47Pi, no tests		 0.3u+0.3s	  0.7		35.2u	  1.2
48Pc, unoptimized		 3.8u+2.4s	  7.7		 5.3u	  8.1
49Pc, optimized		 4.4u+2.3s	  8.4		 4.6u	  9.3
50C, unoptimized		 1.7u+1.8s	  4.4		 2.8u	 15.3
51C, optimized		 2.0u+2.0s	  5.0		 2.5u	 17.1
52
53Note: The times for Pc and C were obtained by running larger
54problems and scaling the run times down appropriately.
55