diff options
-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 e1f0911d..ec3db779 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) -> |