[Coco] Reboot problem with latest NitrOS-9 build

[Robert Gault]

Boisy G. Pitre wrote:
> Robert,
>
> I think this is due to the work that Brett Gordon did to boot the OS using CoCoBoot.  I noticed this behavior too.
>
> I've been unable to get hold of Brett.  He hasn't been answering his emails.
> --
> Boisy G. Pitre
> http://www.tee-boy.com/
>

Boisy,

In case you are not receiving my direct email, take a look at the source code in 
clock2_smart.

A1       tst  ,x+
          beq   A2               found free page so go
          incb                   update page counter
          bpl   A1               still in RAM only, then go
A2       pshs  b                save page #
          andb  #%11100000       modulo MMU blocks
          lsrb                   convert to DAT byte value
          lsrb                   page# * $100 / $2000 = MMU #
          lsrb                   $2000/$100=$20 at 2 bytes per MMU
          lsrb                   then page#/$10 gives answer
          ldd   b,y              get the MMU value
          cmpd  #$333E           is DAT unused
          pshs  cc               save answer
          inc   1,s              update page # for a used page
          puls  cc,b             get back answer and page #
          beq   A1               if unused keep going
          lda   #RAMinUse
          sta   ,-x              flag the memory in use
          stb   <D.SWPage      keep the info for Read

There is some logic here that escapes me. Why after finding a free page and that 
it is unused, does the above code keep looping? Worse still, why is the page 
value always updated, regardless of the $333E test?

I've found through testing that new logic is needed to correct for the 
combination of clock2_smart and the Disto no-Halt drivers. It is crucial to 
preserve the page #.

A1       tst  ,x+
          beq   A2               found free page so go
A6       incb                   update page counter
          bpl   A1               still in RAM only, then go
A4       lda   #2               can't find RAM only memory
          leax  mem_mes,pcr
          ldy   #40
          os9   I$WritLn
          puls  d,x,y,u,pc
A2       pshs  b                save page #
          andb  #%11100000       modulo MMU blocks
          lsrb                   convert to DAT byte value
          lsrb                   page# * $100 / $2000 = MMU #
          lsrb                   $2000/$100=$20 at 2 bytes per MMU
          lsrb                   then page#/$10 gives answer
          ldd   b,y              get the MMU value
          cmpd  #$333E           is DAT unused
*         pshs  cc               save answer
*         inc   1,s              update page # for a used page
*         puls  cc,b             get back answer and page #
          puls  b                get back page#
*         beq   A1
          beq   A6               if unused keep going
          lda   #RAMinUse
          sta   ,-x              flag the memory in use
          stb   <D.SWPage      keep the info for Read

Now the page# increases only if the $333E test fails. I still don't understand 
why we need a free page with used DAT.