Add a full game timer to Kid Chameleon.

[ZTarget]

Lets add a full game timer to Kid Chameleon or your KC mod that will keep track of your play time down to the frame and display at the end of a level.

This game timer functions independent of the level timer and in a way is more accurate. This is because the level timer uses a few shortcuts to

get the hud to update like adding an extra subsecond at the beginning of the map and skipping to the next second when you get a clock item.

The game timer is separate but runs anytime the level clock is ticking and wont reset until you start a new game/reset the system.

Lets take a look at the end result

The last line will display the game time so in this picture it reads 12minutes 57seconds and 36subseconds(out of 60 subseconds)

Just a warning I am not a assembly expert so feel free to correct me or post more optimized solutions.

Before we start be sure to make a backup of your project so you can go back to it if there are any problems!!

Step 1

Open up variables.asm scroll down past Clocks_collected and add these 3 new variables.

Timer_SubSeconds = $FFFFFDD0 ;word
Timer_Seconds = $FFFFFDD2 ;word
Timer_Minutes = $FFFFFDD4 ;word
Should look something like this

Note: we can now monitor these variables in certain emulators to see whats there.

Save and close variables.asm

Step 2

Open kid.asm and search to loc_BE82: Here we are going to set up the timer

copy and paste this line and then the chunk to the highlighted locations in the picture (my line numbers may not match yours so go by the code)

bsr.s timer_update ;timermod

bra.s loc_BEE8 ;timermod skip timer on no time

timer_update: ;timermod
addq.w #1,(Timer_SubSeconds).w
cmpi.w #60,(Timer_SubSeconds).w
bne.s timer_exit
clr.w (Timer_SubSeconds).w
addq.w #1,(Timer_Seconds).w
cmpi.w #60,(Timer_Seconds).w
bne.s timer_exit
clr.w (Timer_Seconds).w
addq.w #1,(Timer_Minutes).w

timer_exit:
rts

Step 3

This is optional but I noticed some branch words can be made to branch shorts just below our new code.

would this save a few cycles to make up a little for our new timer?

manually change the .w to .s in these five locations

Step 4

Next we will be changing the scoreboard at the end of the level to display our timer in the place of the continues display, note that this will not mess with your actual continues.

Manually edit the pink highlighted lines like in the picture. (example: in the first line change #$1C to #$28 )

Then copy and paste the code chunk after the (Number_Continues) line. then comment out the (Number_Continues) line with the semicolon ; like in the picture (pink arrow).

Add some of your own comments if you like. I put ";timermod" next to the changes so I could easily search to these locations.

move.w (Timer_Seconds).w,d0 ;timermod
mulu.w #$64,d0
move.w (Timer_SubSeconds).w,d1
add.w   d1,d0
move.w (Timer_Minutes).w,d1
mulu.w #$2710,d1
add.l d1,d0

Step 5

clear timer on game start

Search to Title_InputLoop:

add these three lines. now when you hit start on the title screen the timer will be set to zero.

we need this because the demo that plays in the intro will run the timer up.

clr.w   (Timer_SubSeconds).w ;timermod clear timer because demo adds time
clr.w   (Timer_Seconds).w
clr.w   (Timer_Minutes).w

Save kid.asm and build then test it out!

edit:

See Part 2 posted below where we are also going to add the level time to the scoreboard.

I moved the link to this running in vanilla kc to the end of the Part 2 post. If you downloaded the old one delete it and get the new one there.

[Molyb]

Looking forward to exploring this feature soon! Seems like it'll be a fun addition.

[ZTarget]

Part 2

Next up we are going to add the level time to the score screen. There are probably a few ways to do this but we are going to use our game timer so that we can keep track of levels without flags and also if the player loses a life and starts from the beginning of the level we want to keep track of that time. So you can think of this as a flag to flag timer.

Again lets take a look at the end result

The level time displays to the left on the last line. The current level was passed in 19 seconds and 27 subseconds.

You can see the time bonus line reads 2410 points this is the time left on the clock multiplied by 10 if we started with 3:00 minutes on the clock and beat the level with 2:41 left, we get 19 seconds.

If you have made any changes to your mod since part one be sure and back up your project.

Step 1

Open up variables.asm scroll down past Clocks_collected again and we are going to add 3 more variables.

Place these after our last three variables
Timer_SSLast = $FFFFFDD6 ;word
Timer_SLast = $FFFFFDD8 ;word
Timer_MLast = $FFFFFDDA ;word
It should look like this

As you may have guessed we are going to be storing our time from the last flag we hit.

Save and close variables.asm

Step 2

Next we are going to add the time to the scoreboard

Open kid.asm and head back to location loc_D4CE:

down 8 lines we see bsr.w    sub_D894

We are going to place our code chunk after this line.

Copy and paste the following.
;timermod2
clr.l d0
clr.l d1
move.w (Timer_SSLast).w,d1
move.w (Timer_SubSeconds).w,d0
sub.w d1,d0
bpl.s skip1 ;branch on positive -if neg add 60 then add 1 to seconds last
add.w #60,d0
addq #1,(Timer_SLast).w

skip1:
move.w d0,d5
move.w (Timer_SLast).w,d1
move.w (Timer_Seconds).w,d0
sub.w d1,d0
bpl.s skip2 ;branch on positive -if neg add 60 then add 1 to minutes last
add.w #60,d0
addq #1,(Timer_MLast).w

skip2:
mulu.w #$64,d0
add.w   d0,d5
move.w (Timer_MLast).w,d1
move.w (Timer_Minutes).w,d0
sub.w d1,d0
mulu.w #$2710,d0
add.l d5,d0

moveq #$34,d5
move.w #$1B0,d1
bsr.w sub_D8BE

move.w (Timer_SubSeconds).w,(Timer_SSLast).w
move.w (Timer_Seconds).w,(Timer_SLast).w
move.w (Timer_Minutes).w,(Timer_MLast).w

move.w #$CC,d7
moveq #0,d6
moveq #$28,d5
;timermod2

Here is the screenshot of what it should look like, I've highlighted the new code.

Thats it! Save kid.asm and build then test it out.

Test it out on vanilla KC here

Kid Chameleon Timer Demo