Prince can survive at 0 HP!

[atrueprincefanfrom18]

Hey,

I was playing the original PoP1 without megahit and I discovered something very very strange. I was in Level 13 (Jaffar Level). I killed Jaffar while I had 1 HP and accidently landed on the first platform as circled in yellow ink from the top platform as circled in yellow color.

Flashing was going on while this happened. It didn't kill the Prince! Check the screenshot:

Kid (Prince) was behaving as if he had enough health and could also run, jump and do all sort of movements. I could even go to the next level from door.

Any idea why this could have happened? Is it because the system doesn't register the changes while flashing is going on?

Thanks!

[Norbert]

Hey,

I was playing the original PoP1 without megahit and I discovered something very very strange. I was in Level 13 (Jaffar Level). I killed Jaffar while I had 1 HP and accidently landed on the first platform as circled in yellow ink from the top platform as circled in yellow color.

Flashing was going on while this happened. It didn't kill the Prince! Check the screenshot:

Screenshot (120)_LI.jpg

Kid (Prince) was behaving as if he had enough health and could also run, jump and do all sort of movements. I could even go to the next level from door.

Any idea why this could have happened? Is it because the system doesn't register the changes while flashing is going on?

Thanks!

A quick way to replicate this is to win from Jaffar while having only 1 potion left.
Then all HP potions are displayed empty.

Alternatively, win with 2 potions left, and then find a way to lose another potion.
For example the method mentioned in atruep's post.

[atrueprincefanfrom18]

Hey,

I was playing the original PoP1 without megahit and I discovered something very very strange. I was in Level 13 (Jaffar Level). I killed Jaffar while I had 1 HP and accidently landed on the first platform as circled in yellow ink from the top platform as circled in yellow color.

Flashing was going on while this happened. It didn't kill the Prince! Check the screenshot:

Screenshot (120)_LI.jpg

Kid (Prince) was behaving as if he had enough health and could also run, jump and do all sort of movements. I could even go to the next level from door.

Any idea why this could have happened? Is it because the system doesn't register the changes while flashing is going on?

Thanks!

A quick way to replicate this is to win from Jaffar while having only 1 potion left.
Then all HP potions are displayed empty.

Alternatively, win with 2 potions left, and then find a way to lose another potion.
For example the method mentioned in atruep's post.

Yes, I tried and it works! But the question still remains, WHY this happens? I am extremely curious to know this...

[David]

It's because of what I wrote here: viewtopic.php?p=25859#p25859

If the prince has 1 HP then it blinks (between 1 HP and 0 HP).
However, this blinking is controlled by the remaining time.
If the timer stops then the blinking stops as well, it remains in the state in which it was when the timer stopped.
So you have a 50% chance that 1 HP will be displayed as 0 HP.

[atrueprincefanfrom18]

Great! Thank you! It answered my question!

[yourantumayel69]

Prince is survive at 9 or 10 HP in level 13 original PoP

[David]

If the prince has 1 HP then it blinks (between 1 HP and 0 HP).
However, this blinking is controlled by the remaining time.
If the timer stops then the blinking stops as well, it remains in the state in which it was when the timer stopped.
So you have a 50% chance that 1 HP will be displayed as 0 HP.

A similar thing can happen if a guard has 1 HP when he kills the prince.
Time stops while the prince is dead (see the bottom of this post), so the guard's HP will stop blinking.

[atrueprincefanfrom18]

More killer fact here!

[David]

(Moved from "Off-Topic" to "Prince of Persia 1 for DOS".)

[Emiliano]

Hi guys, in my mod in progress I found something I haven't seen before, if you have one hit point in level 14 or a guard has it, the only hit point does not blink in this level
Do you need an evidence?
Is it because I use a cracked version?

[atrueprincefanfrom18]

If you have one hit point in level 14 or a guard has it, the only hit point does not blink in this level.

Yes, I tried it works. Maybe because in the original game there is no chance to lose any health point and that's why some code related to Level 14 and Health Points is changed. David can find it.

[Emiliano]

I will keep the no blink one hit point for my sixth mod maybe in my seventh mod I will get a hack for it

[David]

Hi guys, in my mod in progress I found something I haven't seen before, if you have one hit point in level 14 or a guard has it, the only hit point does not blink in this level

That happens because the blinking of the hit point is controlled by the elapsed time, and the timer is stopped on level 14.
See also:
viewtopic.php?p=25859#p25859 -- PoP1 Special Events
viewtopic.php?p=27523#p27523 -- "Prince can survive at 0 HP!"
viewtopic.php?p=28901#p28901 -- one of the hacks for the 30th Anniversary Port SNES mod by Shauing


You could change where the timer stops:

Search: 83 3E 9E 0F 0D 7F 5F
Change: 0D to the level number.

Code: Select all

seg008:24BC 83 3E 9E 0F 0D                       cmp     current_level, 13 ; Special event: time stops if Jaffar died, and on the next level
seg008:24C1 7F 5F                                jg      loc_C142

[Emiliano]

I also found the opposite case, I arrived to level 14 fairly (playing all previous levels) and the one hit point was invisible

[dmitrys]

I had the same issue on level 14 when working on my mod. As mentioned, blinking is driven off the same timer that is responsible for the amount of ticks left before the game is over. When the time stops (typically on level 13 after defeating Jaffar), the blinking stops working. It can get stuck at a tick either when the last hit point is being displayed while blinking or when it is off. So I just created a separate timer for blinking hit points in the SDLPOP source because in my mod the time stops as soon as you face off with Jaffar.