What does instruction LA mean?

What does instruction LA mean?

[Jones Madhuri]

Hello,

I am novice in Power PC assembly code and I am trying
compile in following code (written by someone else)
into head_8xx.S.

This function has instruction like

mfspr r3, IC_CST
LA r4, IC_CST_LEN

However the hardhat assembler doesn't understand the
mnemonic LA, is LA same as add immediate instruction?
addi r4, r4, IC_CST_LEN

Please help!!

Thanks.

M.J.

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Re: What does instruction LA mean?

[Dan Malek]

Jones Madhuri wrote:

> I am novice in Power PC assembly code and I am trying
> compile in following code (written by someone else)
> into head_8xx.S.

Novice or otherwise, you shouldn't be placing any code in
head_8xx.S.  It's a guarantee you won't get Linux to boot.


> mfspr r3, IC_CST
> LA r4, IC_CST_LEN
>
> However the hardhat assembler doesn't understand the
> mnemonic LA,

Because there is no such instruction.  It looks like a
macro that will result in the two instruction pair:
	lis	r4, IC_CST_LEN@h
	ori	r4, r4, IC_CST_LEN@l

You shouldn't be messing around with those cache
management registers......


	-- Dan

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Re: What does instruction LA mean?

[Srinivas Rao.M]

hi madhuri,
 	The LA here is a macro. I am not sure about the linux. but in the
pSOS+ i have seen a macro written in assembly language, which does the
'loading of address to a register' job.

Just check the assembly source files, you may find macro something like this.

  .macro    LA reg,symbol
  lis       reg,%hiadj(symbol)
  addi      reg,reg,%lo(symbol)
  .endm


such macros are written to load the value(constant) in to a register.

cheers,
srini...


On Tue, 27 Mar 2001, Jones Madhuri wrote:

>
> Hello,
>
> I am novice in Power PC assembly code and I am trying
> compile in following code (written by someone else)
> into head_8xx.S.
>
> This function has instruction like
>
> mfspr r3, IC_CST
> LA r4, IC_CST_LEN
>
> However the hardhat assembler doesn't understand the
> mnemonic LA, is LA same as add immediate instruction?
> addi r4, r4, IC_CST_LEN
>
> Please help!!
>
> Thanks.
>
> M.J.
>
> Get email at your own domain with Yahoo! Mail.
> http://personal.mail.yahoo.com/?.refer=text
>
>

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