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| author | Xavier Leroy <xavier.leroy@inria.fr> | 2016-10-04 15:52:16 +0200 |
|---|---|---|
| committer | Xavier Leroy <xavier.leroy@inria.fr> | 2016-10-04 15:52:16 +0200 |
| commit | d2af79a77ed2936ff0ed90cadf8e48637d774d4c (patch) | |
| tree | 09300943e12a98ae80598c79d455b31725271ead /ia32/SelectLongproof.v | |
| parent | a44893028eb1dd434c68001234ad56d030205a8e (diff) | |
| download | compcert-d2af79a77ed2936ff0ed90cadf8e48637d774d4c.tar.gz compcert-d2af79a77ed2936ff0ed90cadf8e48637d774d4c.zip | |
Turn 64-bit integer division and modulus by constants into multiply-high
This trick was already implemented for 32-bit integer division and modulus. Here we extend it to the 64-bit case.
For 32-bit target processors, the runtime library must implement 64-bit multiply-high (signed and unsigned). Tentative implementations are provided for IA32 and PowerPC, but need testing.
Diffstat (limited to 'ia32/SelectLongproof.v')
| -rw-r--r-- | ia32/SelectLongproof.v | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/ia32/SelectLongproof.v b/ia32/SelectLongproof.v index 4cd15fd3..14b0bcce 100644 --- a/ia32/SelectLongproof.v +++ b/ia32/SelectLongproof.v @@ -428,6 +428,20 @@ Proof. - TrivialExists. Qed. +Theorem eval_mullhu: + forall n, unary_constructor_sound (fun a => mullhu a n) (fun v => Val.mullhu v (Vlong n)). +Proof. + unfold mullhu; intros. destruct Archi.splitlong eqn:SL. apply SplitLongproof.eval_mullhu; auto. + red; intros. TrivialExists. constructor. eauto. constructor. apply eval_longconst. constructor. auto. +Qed. + +Theorem eval_mullhs: + forall n, unary_constructor_sound (fun a => mullhs a n) (fun v => Val.mullhs v (Vlong n)). +Proof. + unfold mullhs; intros. destruct Archi.splitlong eqn:SL. apply SplitLongproof.eval_mullhs; auto. + red; intros. TrivialExists. constructor. eauto. constructor. apply eval_longconst. constructor. auto. +Qed. + Theorem eval_shrxlimm: forall le a n x z, eval_expr ge sp e m le a x -> |