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Re: Cloning BOOT13, Pt.2



Lyrical Nanoha wrote:
On Tue, 29 Nov 2005, Linards Ticmanis wrote:

I should add, the code in BOOT13.COM ends with a jump to address $1153; here's what's to be found there:

0153 A9 A9     LDA #$A9
0155 8D 1F 03  STA $031F
0158 A9 60     LDA #$60
015A 8D 20 03  STA $0320
015D 4C 01 03  JMP $0301

Obviously the code that gets loaded to 0301 still needs access to the boot ROM code to do its job, and when it can't find it where it is expected, the second stage of booting won't work.


I wonder how the normal BOOT13 gets around that.

It reenters the boot code at the standard slot-dependent place.

It is common for the second stage boot to do this to read in more
sectors from track 0.  Once RWTS is loaded, things get simpler.

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

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