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List:       gcc
Subject:    Inline Assembly queries
From:       kernel mailz <kernelmailz () googlemail ! com>
Date:       2009-06-27 20:01:51
Message-ID: abe8a1fd0906271249k479e5a87gfe1ee9c02798a234 () mail ! gmail ! com
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Hello All the gurus,

I've been fiddling my luck with gcc 4.3.2 inline assembly on powerpc
There are a few queries

1. asm volatile or simply asm produce the same assembly code.
Tried with a few examples but didnt find any difference by adding
volatile with asm

2. Use of "memory" and clobbered registers.

"memory" -
a. announce to the compiler that the memory has been modified
b. this instruction writes to some memory (other than a listed output)
and GCC shouldn’t cache memory values in registers across this asm.

I tried with stw and stwcx instruction, adding "memory" has no effect.

Is there any example scenerio where gcc would generate different
assembly by adding / removing "memory" ?


-TZ


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