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author | Xavier Leroy <xavier.leroy@inria.fr> | 2016-10-02 16:17:51 +0200 |
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committer | Xavier Leroy <xavier.leroy@inria.fr> | 2016-10-02 16:17:51 +0200 |
commit | f21a6b181dded86ef0e5c7ab94f74e5b960fd510 (patch) | |
tree | 01bb7b59e438c60d12d87d869b6c890095a977f4 /ia32/Asmgen.v | |
parent | a14b9578ee5297d954103e05d7b2d322816ddd8f (diff) | |
download | compcert-f21a6b181dded86ef0e5c7ab94f74e5b960fd510.tar.gz compcert-f21a6b181dded86ef0e5c7ab94f74e5b960fd510.zip |
Improve code generation for 64-bit signed integer division
Implement the 'shift right extended' trick, both in the generic implementation (backend/SplitLong) and in the IA32 port.
Note that now SelectDiv depends on SelectLong, and that some work was moved from SelectLong to SelectDiv.
Diffstat (limited to 'ia32/Asmgen.v')
-rw-r--r-- | ia32/Asmgen.v | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/ia32/Asmgen.v b/ia32/Asmgen.v index 4662f964..ccf2e6fd 100644 --- a/ia32/Asmgen.v +++ b/ia32/Asmgen.v @@ -53,6 +53,13 @@ Definition mk_shrximm (n: int) (k: code) : res code := Pcmov Cond_l RAX RCX :: Psarl_ri RAX n :: k). +Definition mk_shrxlimm (n: int) (k: code) : res code := + OK (if Int.eq n Int.zero then Pmov_rr RAX RAX :: k else + Pcqto :: + Pshrq_ri RDX (Int.sub (Int.repr 64) n) :: + Pleaq RAX (Addrmode (Some RAX) (Some(RDX, 1)) (inl _ 0)) :: + Psarq_ri RAX n :: k). + Definition low_ireg (r: ireg) : bool := match r with RAX | RBX | RCX | RDX => true | _ => false end. @@ -501,6 +508,10 @@ Definition transl_op | Oshrlimm n, a1 :: nil => assertion (mreg_eq a1 res); do r <- ireg_of res; OK (Psarq_ri r n :: k) + | Oshrxlimm n, a1 :: nil => + assertion (mreg_eq a1 AX); + assertion (mreg_eq res AX); + mk_shrxlimm n k | Oshrlu, a1 :: a2 :: nil => assertion (mreg_eq a1 res); assertion (mreg_eq a2 CX); |