Exit Percentage on File Select v1.1

for me a star is appearing instead of the percentage.
what number do I put to replace for percentage?

It appears to be incompatible with the One File, One Player patch. Any way, solid work!

On the next update, can you feature a round-half-up (but away from 100%?)? Like if it lands halfway between two representable values, rounds upwards.

Examples:
Display integer percentage: 0.5% -> 1%
Display tenths percentage: 1.25% -> 1.3%

Moderated with:
Lunar Magic 3.20
Asar 1.71
SA-1 Pack 1.32 (also tested without)
Snes9x 1.60

Surprised this wasn't an existing thing, but it definitely has some usage and it worked fine so it's accepted. Rounding and decimal options all seemed to work well when I messed around, so there should be no issue with its calculation for larger hacks.

Sorry about that. I was wondering about the user-friendlyness towards people editing patches for their hacks.

I know about this, I didn't care to handle it since it can only happen for hacks with 1000+ exits, which is not even possible when using the normal event counter. Even if it was, the percentage can only be computed properly with up to 655 exits (since you do *100, which for higher values would be higher than $FFFF), so this "bug" will never happen.
Also, don't tell me how I should format my code.

Ooh, I think I found a potential bug-- if you make it display a decimal and have roundup being set, it may be possible that the decimal point gets incremented, from 9 to 10, which could increment the integer part from 99 to 100. An easy fix for that is simply check if both if the integer part is 99, and the remainder is attempted to increment past 9, to simply display 99.9%.



Also, I would recommend indenting the if statement, so that the nested if statement is double-indented for anyone wanting to edit the patch for their hacks to understand it easier.

An easy way to deal with displaying percentages with decimals is by using fixed-point arithmetic. Where instead of dealing with x/100, you deal with x/1000. So instead of ExitsFound * 100 / TotalExits, you do ExitsFound * 1000 / TotalExits, and after the hexdec display, note this:

And when rounding via that, will round upwards by 0.1% automatically.

Perhaps, I made my own percentage converter (CTRL+F “ConvertToPercentage”). This one rounds 1/2 up, and you can use the Y register to check for misleading displays.

Updated to v1.1: now you can also display a decimal digit for the percentage for more accurate values.

Small update: added a check so 99 isn't rounded to 100 when using the RoundUp option, added support for values between 101% and 199% and changed mode 7 multiplication regs to normal regs since the results were wrong when having more than 127 exits.

In that case just set !RoundUp to 0, problem solved

Be careful that when you have more than 100 exits, and you have the round up setting, there is a potential that the game may misleadingly display 100% indicating you got all the exit despite you only got 99.99%. A way to avoid that is by checking after you divide by the number of exits, the modulo is usually in between 0 and the number of exits. During the rounding upwards, check if it went from 99 to 100, then simply display 99%.

How to calculate a value into a percentage, using only integers: Show/Hide

Also, interesting you use mode 7 registers to handle multiplication instead of this instead: Percentage = (ExitsFound*100)/Exits, take the number of exits found, write it to $4202, write #100 to $4203, wait 8 cycles, $4216 should contain the product, then write that to $4204, write the total exits into $4206, wait 16 cycles, and now $4214 is the percentage. You may read $4216 to see should the number round upwards. Probably because this is a faster multiplication.

Code

	;A = number of exits found
	stz $211B		;>Reset the register just in case.
	sta $211B		;>Write number of exits found to multiplicand A
	lda.b #100		;\Write 100 (the max in percentage) into multiplicand B (writing a number here is treated as that, divided 256, for fixed point)
	sta $211C		;/
	lda $2135		;>Load the product's high byte, high byte instead of lowest byte (results in a scale factor by 256) because B is scaled by 1/256 (due to fixed point calculation)
	sta $4204		;\Write product to dividend
	lda $2136		;|
	sta $4205		;/
	lda.b #!TotalExits	;\Divide by total exits
	sta $4206		;/
	lda [$00],y		;\ Waste 13 cycles
	lda ($00,s),y		;/
	lda $4214		;>And that is our percentage

Remember that the SNES does not have floating point arithmetic, only integers, thus you have to handle them using fractions since dividing by a larger number always results 0 (you cannot do X/Y * 100, you'll need to simplify that via using invisible denominator), so 100 is now 100/1, now multiply the two fractions would result in (X/Y) * (100/1) &rightarrow (X*100) / (Y*1) → X * 100 / Y

Very cool