Posted By
Majikeyric
on 2016-01-21
12:10:46
 |  $ffd5 (LOAD) question
Hi,
I try to understand something, I have coded a normal kernal load routine which works well.
But why does it stop working when I disable the Raster IRQs (I enable timer#1 IRQ instead, $FF0a=$08) ?
And..... does $FFD5 do SEI or CLI ?
Many thanks.
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Posted By
gerliczer
on 2016-01-21
12:28:39
| Re: $ffd5 (LOAD) question
It is quite hard to answer your questions without actually knowing what you are doing.
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Posted By
Majikeyric
on 2016-01-21
13:51:55
| Re: $ffd5 (LOAD) question
In general, is there a reason for $FFD5 to not work if the raster IRQs are disable ?
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Posted By
siz
on 2016-01-21
15:43:57
| Re: $ffd5 (LOAD) question
If you use the serial bus or tape as input for load the KERNAL uses TED timer interrupts for timing of the I/O. If you disable the IRq it won't reenable it so LOAD (and generally any I/O) will halt because it will wait for an interrupt which never comes.
The TCBM bus (1551 drive) does not use interrupts.
This is the reason why people tend to use the so called IRq-loaders which allow you to use (or disable) interrupts for your own purposes during I/O.
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Posted By
Majikeyric
on 2016-01-22
11:27:11
| Re: $ffd5 (LOAD) question
Oh thanks siz! 
I use the serial bus,
but I don't disable every IRQs, only the raster IRQs and I enable Timer#1 IRQs (for 50hz stuff on PAL and NTSC),
Does the KERNAL modify $ff0a ?
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