IBM PPC440X5 Manual de usuario descargar pdf (Pagina 446)

100

101

wrtee

Write External Enable

PPC440x5 CPU Core User’s Manual Preliminary

Page 446 of 589

instrset.fm.

September 12, 2002

wrtee

Write External Enable

MSR[EE] ← (RS)

MSR[EE] is set to the value specified by bit 16 of register RS.

If instruction bit 31 contains 1, the contents of CR[CR0] are undefined.

Registers Altered

• MSR[EE]

Invalid Instruction Forms:

• Reserved ﬁelds

Programming Notes

Execution of this instruction is privileged.

This instruction is typically used as part of a code sequence which can provide the equivalent of an atomic

read-modify-write of the MSR, as follows:

mfmsr Rn #save EE in Rn[16]

wrteei 0 #Turn off EE (leaving other bits unchanged)

• #Code with EE disabled

•

wrtee Rn #restore EE without affecting any MSR changes that occurred in the disabled code

wrtee RS

31 RS 131

0 6 11 21 31

1 2 ... 441 442 443 444 445 446 447 448 449 450 451 ... 589 590

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IBM PPC440X5 Manual de usuario Pagina 446

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