diff options
| author |  xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e> | 2011-08-27 07:15:26 +0000 |
|---|---|---|
| committer | xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e> | 2011-08-27 07:15:26 +0000 |
| commit | e8bd77565422ab8e6d2fdd4ec7d5e7e4916ff2bd (patch) | |
| tree | 18b2a9efc754ba386781896dee70971a7f8f1806 /ia32/PrintAsm.ml | |
| parent | ca0117ca268873766ac4fda3771295842b17fcd6 (diff) | |
Watch out for min_int / -1
git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1727 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
Diffstat (limited to 'ia32/PrintAsm.ml')
| -rw-r--r-- | ia32/PrintAsm.ml | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/ia32/PrintAsm.ml b/ia32/PrintAsm.ml index e1f0911..ec3db77 100644 --- a/ia32/PrintAsm.ml +++ b/ia32/PrintAsm.ml @@ -559,8 +559,18 @@ let print_instruction oc = function fprintf oc " xorl %%edx, %%edx\n"; fprintf oc " divl %a\n" ireg r1 | Pidiv(r1) -> + let lbl1 = new_label() in + let lbl2 = new_label() in + fprintf oc " cmpl $-1, %a\n" ireg r1; + fprintf oc " je %a\n" label lbl1; fprintf oc " cltd\n"; - fprintf oc " idivl %a\n" ireg r1 + fprintf oc " idivl %a\n" ireg r1; + fprintf oc " jmp %a\n" label lbl2; + (* Division by -1 can cause an overflow trap if dividend = min_int. + Force x div (-1) = -x and x mod (-1) = 0. *) + fprintf oc "%a: negl %a\n" label lbl1 ireg EAX; + fprintf oc " xorl %a, %a\n" ireg EDX ireg EDX; + fprintf oc "%a:\n" label lbl2 | Pand_rr(rd, r1) -> fprintf oc " andl %a, %a\n" ireg r1 ireg rd | Pand_ri(rd, n) -> |