[OpenBIOS] PowerPC special purpose registers

[Programmingkid]

You know how you see messages about writing to missing registers like these:

 OS 9.2] Trying to write invalid spr 0 (0x000) at 00f113c0
11:26:23.910 WARNING [Mac OS 9.2] Trying to read invalid spr 0 (0x000) at 00f113c8
11:26:24.055 WARNING [Mac OS 9.2] Trying to write privileged spr 955 (0x3bb) at 00f164b8
11:26:24.055 WARNING [Mac OS 9.2] Trying to write invalid spr 959 (0x3bf) at 00f16520
11:26:24.055 WARNING [Mac OS 9.2] Trying to read invalid spr 959 (0x3bf) at 00f16528
11:26:24.056 WARNING [Mac OS 9.2] Trying to write invalid spr 944 (0x3b0) at 00f1653c
11:26:24.056 WARNING [Mac OS 9.2] Trying to read invalid spr 944 (0x3b0) at 00f16544
11:26:24.056 WARNING [Mac OS 9.2] Trying to write invalid spr 951 (0x3b7) at 00f16550
11:26:24.056 WARNING [Mac OS 9.2] Trying to read invalid spr 951 (0x3b7) at 00f16558
11:26:24.204 WARNING [Mac OS 9.2] Trying to write privileged spr 955 (0x3bb) at 00f164b8
11:26:24.204 WARNING [Mac OS 9.2] Trying to write invalid spr 959 (0x3bf) at 00f16520
11:26:24.204 WARNING [Mac OS 9.2] Trying to read invalid spr 959 (0x3bf) at 00f16528
11:26:24.204 WARNING [Mac OS 9.2] Trying to write invalid spr 944 (0x3b0) at 00f1653c
11:26:24.204 WARNING [Mac OS 9.2] Trying to read invalid spr 944 (0x3b0) at 00f16544
11:26:24.205 WARNING [Mac OS 9.2] Trying to write invalid spr 951 (0x3b7) at 00f16550
11:26:24.205 WARNING [Mac OS 9.2] Trying to read invalid spr 951 (0x3b7) at 00f16558

Should these registers be implemented? Maybe Apple expected these registers to be available on their hardware.

Using these files:
http://www.nxp.com/files/32bit/doc/ref_manual/MPC7450UM.pdf page 1-36
and http://www.nxp.com/files/32bit/doc/data_sheet/MPC604.pdf page 19,
as a guide, here is what I found out:

SPR	Name

944	Monitor Control Register 2
951	Breakpoint Address Mask Register1
955	Sampled Instruction Address 1 
959	Sampled Data Address 		* PowerPC 604 only

My current theory is there might be implementation details that are off in QEMU's emulated PowerPC 750 processor. The only way I know how to test this out is run QEMU in KVM mode on PowerPC hardware. I'm hoping someone out there has this setup available and can tell us if Mac OS 9.2 works better in KVM mode or not.