PPC Register classification

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r0localcommonly used to hold the old link register when building the stack frame
r1dedicatedstack pointer
r2dedicatedtable of contents pointer
r3localcommonly used as the return value of a function, and also the first argument in
r4–r10localcommonly used to send in arguments 2 through 8 into a function
r11–r12local
r13–r31global
lrdedicatedlink register; cannot be used as a general register. Use mflr (move from link register) or mtlr (move to link register) to get at, e.g., mtlr r0
crdedicatedcondition register

More :http://www.csd.uwo.ca/~mburrel/stuff/ppc-asm.html

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