Platform Game DevKit thread
Lesson for all: Never use HALT to wait for VBlank.
I see it too often, while a poll on JIFFY is just as easy and you’re not saving yourself development time by not doing that. Using HALT will bite you in the ass someday, as evidenced here 
, and cost you much more time to investigate and deal with. Be it either by your own doing because you forgot you were relying on the single-interrupt assumption when you introduced that line interrupt or sound chip interrupt, or by some TSR / 3rd party hardware / fast CPU/ MSX3 in use by the user.
Lesson for all: Never use HALT to wait for VBlank.
I see it too often, while a poll on JIFFY is just as easy and you’re not saving yourself development time by not doing that. Using HALT will bite you in the ass someday, and cost you much more time to investigate and deal with, as evidenced here . Be it either by your own doing because you forgot you were relying on the single-interrupt assumption when you introduced that line interrupt or sound chip interrupt, or by some TSR / 3rd party hardware / fast CPU/ MSX3 in use by the user.
Halting makes the cpu to rest, it works cold, also it consumes less power.
See that I fixed, and still using HALT, just checking for the vblanks counter after the half, if it reached the required count it escapes from the loop, nothing can be more simple than that.
flyguille: That’s not my point . Insert a halt in the JIFFY poll loop for all I care, if you must.
Just never use HALT as a means to wait for VBlank.
The single-interrupt assumption is a recipe for problems. You’ve found out that it was a bad idea, so I just wanted to relay the warning to the other coders out there, as a best-practice advice .
flyguille: That’s not my point . Insert a halt in the JIFFY poll loop for all I care, if you must.
Just never use HALT as a means to wait for VBlank.
The single-interrupt assumption is a recipe for problems. You’ve found out that it was a bad idea, so I just wanted to relay the warning to the other coders out there, as a best-practice advice .
can you elaborate more, I don't understand you.
Lesson for all: Never use HALT [as a means/way] to wait for VBlank.
In other words; “Advice to all programmers reading this: If you want to wait for VBlank, do not just use HALT, but check if JIFFY increments. Using only HALT assumes there is only one interrupt, which is bad practice. Spending a tiny bit of time to write a simple loop which checks JIFFY is totally worth it, because the odds are high that it will cost you a lot more time and headaches in the future if you don’t.”
Hope it’s more clear now . Advice wasn’t really meant for you anyway because you already found out the hard way, hehe.
Lesson for all: Never use HALT [as a means/way] to wait for VBlank.
In other words; “Advice to all programmers reading this: If you want to wait for VBlank, do not just use HALT, but check if JIFFY increments. Using only HALT assumes there is only one interrupt, which is bad practice. Spending a tiny bit of time to write a simple loop which checks JIFFY is totally worth it, because the odds are high that it will cost you a lot more time and headaches in the future if you don’t.”
Hope it’s more clear now . Advice wasn’t really meant for you anyway because you already found out the hard way, hehe.
I found out in just 5 minutes of work when I notice something odd about the fps historygram.
Because I simply connect event A with event B (using the brain), and it took me few seconds to do that.
Then to open the source file, took a bit more, maybe because drinking the coffee, is to say, where else you will find a wrong game speed?.
Ofcourse, I agree with you, doing just HALTs, and not checking what kind of /ints was, is a good source of problems for games already released and closed.
In konami games, runs the game routines (any part of the game) on the $F9DF hook, and there is a HALT but it is a blind HALT, just HALT + JR -3, to wast the free time and for stop the main run of the game (lets say the main cpu "thread").
In other words; “Advice to all programmers reading this: If you want to wait for VBlank, do not just use HALT, but check if JIFFY increments. Using only HALT assumes there is only one interrupt, which is bad practice. Spending a tiny bit of time to write a simple loop which checks JIFFY is totally worth it, because the odds are high that it will cost you a lot more time and headaches in the future if you don’t.”
Hope it’s more clear now . Advice wasn’t really meant for you anyway because you already found out the hard way, hehe.
would you be so kind to show an example of how to use it?
thanks
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