INFO: On a MIPS Processor You Can Enable the DE Bit in the OEMInit Function (262431)

SUMMARY

On a MIPS processor, a kernel variable, basePSR, is used immediately upon return from the OEMInit function to load the CP0 register. The diagnostic bit (DE) is not altered from the basePSR value set during boot, so the DE bit set into basePSR in the OEM Adaptation Layer (OAL) OEMInit function of the will remain in effect.

MORE INFORMATION

To implement a change to the basePSR value, include the following code in your OEMInit function:

#ifdef _MIPS_
#define pBasePSR		((DWORD*) (KPAGE_BASE+0x0890))

    *pBasePSR = 0x10000;
#endif

The CP0 register is reloaded from the basePSR value often by the Windows CE kernel. Any change to the DE bit directly in the CP0 register, such as in startup code, will not remain in effect.

The DE bit must be set to disable parity check on platforms that do not support parity checking. If the bit is not set, a cache error exception may be generated.