My Diaries

A Lurid Tale of Obsession, Depravity, Wits and Attempted Wit

Friday April 9, 2004

(GT1 version 1.1) Favourite GameShark Code -- Tuned All Civics

My current favourite GameShark Code for GT1 is one which changes the AI field in the Hard-Tuned Series to always be all Honda Civics.

Using the address list in November 26, 2000 I want to arrange that the pointer to the entrant list for the Hard-Tuned Series points not to the complete list, but to a list consisting only of the Honda Civic 3 door. Since that car occurs last, the easiest way to accomplish that is to simply change the pointer to point to the Honda Civic 3 door instead of its normal value which points to the NSX'93.

That is:

Actually, how that accomplishes this is not all that obvious. Even to me as I read it a few months after creating it. My previous page indicates that the table for the event begins at 8008F5BC. Now, the pointer to the list of entrants occurs 3 full words (12 bytes) after that, or 8008F5C8. We only need to change the low-order 16 bits of the word, which, in the PlayStation architecture, occur first.

The original value of that full-word pointer location was 80090A24.

From my previous page...

So, to bump the pointer all the way until it points to the Civic 3 door we need to add 7*4, or 28(decimal, i.e. 1C hex), to its original value of 80090A24, giving 80090A40.

To prevent the code from being in effect during times when it shouldn't I need a "guard". The "guard" I happened to use was D008C220 6E68. This is in fact testing for the value "hn" in that location, checking that the code name of the NSX'93 ("hnsrn") is at that location, where it should be during the game mode of "in a race, but not racing". It turns out that is sufficient to make sure the code comes into effect only when we want it.

So the complete code is

I really enjoy this code because it lets cars like used Eunos Roadsters or the del Sol verion S win the Hard-Tuned Series. It's relatively easy to win, but at least some of the Civics in each race are quite aggressive, so the series can be somewhat sporting.

It is cheating, but only somewhat as long as you use only very weak cars yourself, since concentration is needed to keep competitive. Myself, I never save a game after having used this code, but race these races in "temporary" games only.