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Re: explaination of some gcc functions
I'm having trouble in understanding the term sequnce in an insn
chain.get_insns() actually returns the current instruction.What does
the term "sequence" mean,as the name suggests it must be a sequence of
instructions ,but in an instruction chain,a single element will be an
instruction ,then what is meant by sequence.
When push_topmost_sequence is called ,it should push a sequence of
instructions ,but an element of insn chain is a single
instruction,then which sequence will be pushed.
Suppose following is a sequnce of instructions.
1) entry_insns = get_insns ();
2) push_topmost_sequence ();
3) emit_insn_after (entry_insns, get_insns ());
4) pop_topmost_sequence ();
In 1) current insn is saved in entry_insns. what is happening in In
2).Is sequence differnet from insn in an insn chain ,any example will
be helpful.
In 3) instruction the entry_insns is being put after the instruction
obtained through get_insns() .But does get_insns() also increaments
the current instruction pointer.If not then shouldn't the same
instruction be emitted in 3).
Now again which sequnce is being poped out in 4).
On 7/1/06, Eric Christopher <echristo@apple.com> wrote:
kernel coder wrote:
> hi,
> I'm trying to understand the backend code of gcc for MIPS
> architecture.I'm having some trouble while understanding following
> functions.
I think most of these are obvious, what problems in specific are you
having with them?
-eric