Re: C128D floppy drive ROM

g.j.p.a.a.baltissen_at_kader.hobby.nl
Date: 2000-01-17 22:43:08

Hallo William,

> ......
> A65A  LDA $1860
> A65D  BRK
> 
> The interrupt vector ist FE67
> 
> FE67 JMP($02A9)
> 
> At this point, the RAM has not even been cleared, let alone filled with
> values.  The drive should crash at this point, but it doesn't.
> 
> A65A is the beginning of the chip initialization routine in the 1571.  It
> jumps to several locations and then jumps back and finishes the
> initialization.
> 
> The routine above makes no sense to me.
> 
> Does anyone have an explanation?

Yes, I do. IMHO the above disassembly is wrong. It should be:

A65A    LDA #$02
A65C    STA $1800
A65F    LDA #$20 
A661    STA $1801
A664    JMP $FF18   ; back to RESET-routine

Groetjes, Ruud

> 
> 
> -
> This message was sent through the cbm-hackers mailing list.
> To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tcm.hut.fi.
> 


-
This message was sent through the cbm-hackers mailing list.
To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tcm.hut.fi.

Archive generated by hypermail 2.1.1.