Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site iuvax.UUCP Path: utzoo!linus!decvax!harpo!ihnp4!inuxc!iuvax!saj From: saj@iuvax.UUCP Newsgroups: net.lang Subject: Re: Self-modifying code - (nf) Message-ID: <116@iuvax.UUCP> Date: Wed, 15-Feb-84 15:10:35 EST Article-I.D.: iuvax.116 Posted: Wed Feb 15 15:10:35 1984 Date-Received: Thu, 16-Feb-84 06:06:29 EST Sender: saj@iuvax.UUCP Organization: Indiana U, Bloomington Lines: 19 #R:fortune:-215700:iuvax:11800008:000:684 iuvax!apratt Jan 8 00:38:00 1984 I found another use for self-modifying code: speed. I wrote a graphics package (a pretty simple-minded one) for the IBM PC, and found that my line-drawing routine had two spots where one of three things needed doing: increment x (or y), decrement x (or y), do nothing to x (or y). I could have loaded the proper add-on value (-1, 0, or 1) into a memory location or register and used an add instruction, but it was MUCH faster to have the program "poke" an increment, decrement, or NOP instruction into the appropriate spot. One (inprecise) comparison (timed with a watch) showed a 20% speed increase (approx. 4 seconds in 20). -- Allan Pratt ...ihnp4!iuvax!apratt