From: Baltissen, GJPAA (Ruud) (ruud.baltissen_at_abp.nl)
Date: 2005-04-22 15:40:46
Hallo Spiro,
> Of course it is the end. I am comparing the switching from
> write to read mode, which is different. Thus, I am not
> comparing apples with pears, but apples with apples. ;-)
OK, I really hope I know what you mean by now :)
The only difference I see is that one switch is done directly and the other
by calling a subroutine. The only two reasons I can think of are that 1)
someone forgot that there existed a routine for this at all and 2) to save
time. But the last argument is contradicted by calling the routine $F5F2 at
$F5D9. This routine takes a lot of time. Another details that strengthens
1): when going through the sources, I encountered several routines that are
only called from one place. It is possible that (one of) the programmer(s)
thought that he/someone else would use it later again.
> They are just there to make sure all 325 (GCR) byte are
> written to the disk.
No.
The first 69 bytes are written from $FCE9 to $FCF5.
The next 256 bytes are written from $FCF7 to $FD02.
Then several $55 bytes are written from $FD04 to $FD10.
Then a check is done to see if it was the last sector: $FD12 to $FD1C. If it
was not the last sector, the routine branches to $FCB1.
If it was the last sector indeed, then your two BVC's come in view, not
earlier.
BTW, I have to correct one of my statements: only ONE extra $55 byte is
written after the last sector. The first BVC is the 'acknowledgement' of the
last $55 written by the routine in $FD04/$FD10.
> What I want to say: The "write" routine inside the DC only writes 324
> (GCR) byte (possibly, plus some bits), not all 325 byte.
I disagree with you as can be seen above.
> From my oversations, IMHO, the 1541 write routine for writing
> a block is wrong, but it does not do any harm.
IMHO the way you see it is wrong :) No offence meant. It seems that there is
only one solution:
HELP, CAN ANYBODY ELSE ON THIS LIST HAVE A LOOK AT OUR PROBLEM, PLEASE ????
--
___
/ __|__
/ / |_/ Groetjes, Ruud
\ \__|_\
\___| URL: Ruud.C64.org
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