[Qemu-devel] [Patch] target-ppc mtcrf instruction not recognized

[Pierre d'Herbemont]

Hi,

I have been playing with ppc-darwin-user. And I have to say that qemu- 
ppc is too strict with ppc opcode validity:
On Mac OS X binary release called Tiger (or 10.4), the __bzero  
function [1] contains a mtcrf, which has been translated to  
0x7c901120, by Apple's as. Current qemu rejects it, saying it is  
invalid. According to the IBM Specification the mtcrf instruction  
[2], contains reserved flags, for which the values are unknown. qemu  
assumes that those are set to 1, which is obviously wrong. The  
attached patch provides a fix.

The mtcrf case might not be the only case in which such a situation  
occurs. That would need a special attention, though being strict is  
better than letting pass.

Pierre.

[1] http://fxr.watson.org/fxr/source/osfmk/ppc/commpage/bzero_32.s? 
v=DARWIN8#L98
[2] http://publibn.boulder.ibm.com/doc_link/en_US/a_doc_lib/aixassem/ 
alangref/mtcrf.htm

qemu_mtcrf.diff.txt
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