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Flavioweb
Registered: Nov 2011
Posts: 463 |
Drive code: 1541/81 code conversion.
I have a simple question (for you experts).
This is a drivecode for 1541:
DRV_5BYTELOOP
BVC DRV_5BYTELOOP ; Wait for data from the R/W head
CLV
LDA $1C01
STA (BUFLO),Y
INY
CPY #$05 ; Read 5 GCR bytes
BNE DRV_5BYTELOOP
RTS
How can i translate it to work on a 1581? |
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cadaver
Registered: Feb 2002
Posts: 1160 |
Don't remember if I've asked this, but do you do anything special to speed up IFFL scanning on 1581/FD/HD? I never got around to that, as didn't use IFFL in an actual production so far, and only built the 1541 proof-of-concept routine. |
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Flavioweb
Registered: Nov 2011
Posts: 463 |
I don't know how much time is needed by 81/Fd/HD to complete the seek process... maybe fast enough...
But i have no code to test now.
Maybe MagerValp tried something about this... |
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Krill
Registered: Apr 2002
Posts: 2980 |
Is there a need to speed up scanning on 1581? Loading a random block, the entire track it is located on is read in a revolution or two, then the links can be walked in no time. Repeat for the rest of the file's tracks.
That said, one can always implement scanning on demand, such that a seek is only performed when loading. |
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MagerValp
Registered: Dec 2001
Posts: 1078 |
Quote: Don't remember if I've asked this, but do you do anything special to speed up IFFL scanning on 1581/FD/HD? I never got around to that, as didn't use IFFL in an actual production so far, and only built the 1541 proof-of-concept routine.
On 1581 I buffer a track in the drive and then read all 40 t/s links from ram in one sweep. On CMD FD/HD the C64 requests sectors from the drive but only transfer the first two bytes. The 1581 version is a lot faster. |
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