RE: cpp init & machine check

"bne" is "branch not equal", and it implements the "for" loop.  The three
instructions above the bne increment the pointer "constructor", dereference it,
and compare it to 0x0.  If it's not zero, the bne instruction repeats the loop
until it is.

What is the value in R12 (and CTR) when you get the machine check ?

Does the table stored at 0x405340 (_ctors) appear to contain a list of valid
function addresses, terminated by a NULL (0x0) ?  R31 should point to one of the
entries in the table, and R12 should have the address stored in the table.

At first blush, I'd guess you're trying to run this from internal RAM, and your
program is too large.  I don't have my manual handy, but ISTR 0x405340 is a bad
address.

Randall Young
Senior Software Engineer
NavCom Technology, Inc
A John Deere Company

> Hey guys,
> I'm really stuck on this constructor function in the cpp-init. For
> some reason Codewarrior keeps giving me machine check exceptions
> during the branch command shown below:
>
> {
> 003FA35C: 9421FFF0  stwu     SP,-16(SP)
> 003FA360: 7C0802A6  mflr     r0
> 003FA364: 90010014  stw      r0,20(SP)
> 003FA368: 93E1000C  stw      r31,12(SP)
> 	voidfunctionptr *constructor;
>
> 	/*
> 	 *	call static initializers
> 	 */
> 	for (constructor = _ctors; *constructor; constructor++) {
> 003FA36C: 3C600040  lis      r3,64
> 003FA370: 3BE35340  addi     r31,r3,21312
> 003FA374: 48000014  b        __init_cpp+0x28 (0x3fa388)
> 		(*constructor)();
> 003FA378: 819F0000  lwz      r12,0(r31)
> 003FA37C: 7D8903A6  mtctr    r12
> 003FA380: 4E800421  bctrl               //MACHINE CHECK
> 	}
> 003FA384: 3BFF0004  addi     r31,r31,4
> 003FA388: 801F0000  lwz      r0,0(r31)
> 003FA38C: 28000000  cmplwi   r0,0x0000
> 003FA390: 4082FFE8  bne      __init_cpp+0x1c (0x3fa378)  //branch
> to   003FA378
>
> }
> 003FA394: 83E1000C  lwz      r31,12(SP)
> 003FA398: 80010014  lwz      r0,20(SP)
> 003FA39C: 7C0803A6  mtlr     r0
> 003FA3A0: 38210010  addi     SP,SP,16
> 003FA3A4: 4E800020  blr
>
> I'm not sure what is the bne instruction for, if anyone can help I
> would really appreciated.
>
> Lei
>
>
>
>
>
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