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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/Asm.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/Asm.v')
| -rw-r--r-- | ia32/Asm.v | 10 |
1 files changed, 8 insertions, 2 deletions
@@ -164,9 +164,9 @@ Inductive instruction: Type := | Pimull_ri (rd: ireg) (n: int) | Pimulq_ri (rd: ireg) (n: int64) | Pimull_r (r1: ireg) -(* | Pimulq_r (r1: ireg) *) + | Pimulq_r (r1: ireg) | Pmull_r (r1: ireg) -(* | Pmulq_r (r1: ireg) *) + | Pmulq_r (r1: ireg) | Pcltd | Pcqto | Pdivl (r1: ireg) @@ -718,9 +718,15 @@ Definition exec_instr (f: function) (i: instruction) (rs: regset) (m: mem) : out | Pimull_r r1 => Next (nextinstr_nf (rs#RAX <- (Val.mul rs#RAX rs#r1) #RDX <- (Val.mulhs rs#RAX rs#r1))) m + | Pimulq_r r1 => + Next (nextinstr_nf (rs#RAX <- (Val.mull rs#RAX rs#r1) + #RDX <- (Val.mullhs rs#RAX rs#r1))) m | Pmull_r r1 => Next (nextinstr_nf (rs#RAX <- (Val.mul rs#RAX rs#r1) #RDX <- (Val.mulhu rs#RAX rs#r1))) m + | Pmulq_r r1 => + Next (nextinstr_nf (rs#RAX <- (Val.mull rs#RAX rs#r1) + #RDX <- (Val.mullhu rs#RAX rs#r1))) m | Pcltd => Next (nextinstr_nf (rs#RDX <- (Val.shr rs#RAX (Vint (Int.repr 31))))) m | Pcqto => |