[B2-devel] [Patch] Init NVRAM to enable PPC memory manager

[Michael S. <msb...@me...>]

Attached is a patch to SheepShaver, to fix a SIGSEGV crash that occurs  
when booting a new machine with OS 7.5.

One of the bytes in the xPRAM portion of the NVRAM controls which  
version of the system memory manager is used by OS 7.5: the legacy  
680x0 memory manager or the PPC memory manager (aka the "Modern Memory  
Manager"). OS 7.5 is supposed to be able to use either one, but for  
some reason SheepShaver crashes on boot if the 680x0 version is used.

Later Mac OS versions don't have this problem. They don't support the  
680x0 version, so they force the PPC version to be used.

The fix is to have SheepShaver initialize the NVRAM to use the PPC  
memory manager. Note: This is supposed to be the default in OS 7.5.

This affects when a new NVRAM file is used, or when it is initialized  
after doing zapping the PRAM.