How to use ppcbug to debug my program with mmu?

[Gong Zhuo]

Hi:
   I am using MVME2600 SBC and I want to debug my program under PPCbug.
According the PPCbug Firmware Package User's Manual chapter 2, a program
with mmu enable should be debugged using PPCbug if some rules are obeyed.
   Those address ranges
         0x0 -- 0x0fffffff,
         0x10000000 -- 0x1fffffff ,
         0xe0000000 -- 0xefffffff,
         0xf0000000 -- 0xffffffff
   have been mapped from physical address to logical address 1 to 1 using
BAT mothed .  Exception vectors 0x100 , 0x700, 0xc00, 0x2000 and spr272,
spr273, spr274, spr275 are not being used.
   I write the code like this under ppcbug at address 0x40000:
          1.     initial all the BAT register
          2.     isync
          3.     msr | 0x30  ==> msr    # open the mmu
          4.     do sth. else
    But it always not come back to PPC1-bug> status after I use command
'T'to singlestep run step 3.
    I also used the mothed like this :
          1.     initial all the BAT register
          2.     isync
          3.     msr | 0x30  ==> srr1    # open the mmu
          4.     logical address of 6. => srr0
          5.     rfi
          6.     do sth. else
    The same error happened when singlestep 5.

   Can this code be debugged under ppcbug? If can , how?


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