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Assembly Help!!

Hi, there.

I'm kind of a newbie in embedded programming. Now, I'm customizing imported BSP to fit our new platform, but Assembly language is killing me. I hope your help and thanks, In advance.

  • We are using Intel XScale CPU, gcc and as.

Here are my questions.

1) It's a MMU page table making code. I don't understand '->' marked parts. It seems like to me that they're macro commands in macro definition. I mean, It seems like using macro command even though PT_ENTRY macro definition is not yet finished. and why they need some arguments within double quote??? What does that mean???

.MACRO PT_ENTRY base,x,ap,p,d,c,b,total=0 .if \total .if \total

Reply to
Marty
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It's a recursive macro. Here's a simple example:

.MACRO RECURSIVE_TEST value .if \value .long \value RECURSIVE_TEST "(\value-1)" .else .long 0x9999 .endif .ENDM

Write out by hand what will be generated if you call this RECURSIVE_TEST macro with a value of, say, 4... it will create the following output:

.long 4 .long 3 .long 2 .long 1 .long 0x9999

When you understand why, you'll be able to understand the PT_ENTRY macro.

The quotes are probably just to get around some text substitution rules in the assember input format.

Cheers,

John

Reply to
John Williams

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