min_caml_start まわりのコードを確認

C言語とのインターフェースとなるmin_caml_start まわりのソースを確認してみる。

PowerPC版ののemit.mlのコードが参考になりそう。

全体のソース

code:ml

let f oc (Prog(data, fundefs, e)) =

Format.eprintf "generating assembly...@.";

if data <> [] then

(Printf.fprintf oc "\t.data\n\t.literal8\n";

List.iter

(fun (Id.L(x), d) ->

Printf.fprintf oc "\t.align 3\n";

Printf.fprintf oc "%s:\t # %f\n" x d;

Printf.fprintf oc "\t.long\t%ld\n" (gethi d);

Printf.fprintf oc "\t.long\t%ld\n" (getlo d))

data);

Printf.fprintf oc "\t.text\n";

Printf.fprintf oc "\t.globl _min_caml_start\n";

Printf.fprintf oc "\t.align 2\n";

List.iter (fun fundef -> h oc fundef) fundefs;

Printf.fprintf oc "_min_caml_start: # main entry point\n";

Printf.fprintf oc "\tmflr\tr0\n";

Printf.fprintf oc "\tstmw\tr30, -8(r1)\n";

Printf.fprintf oc "\tstw\tr0, 8(r1)\n";

Printf.fprintf oc "\tstwu\tr1, -96(r1)\n";

Printf.fprintf oc "#\tmain program starts\n";

stackset := S.empty;

stackmap := [];

g oc (NonTail("_R_0"), e);

Printf.fprintf oc "#\tmain program ends\n";

(* Printf.fprintf oc "\tmr\tr3, %s\n" regs.(0); *)

Printf.fprintf oc "\tlwz\tr1, 0(r1)\n";

Printf.fprintf oc "\tlwz\tr0, 8(r1)\n";

Printf.fprintf oc "\tmtlr\tr0\n";

Printf.fprintf oc "\tlmw\tr30, -8(r1)\n";

Printf.fprintf oc "\tblr\n"

mainから呼び出し ~ プログラム開始直前

code:ml

Printf.fprintf oc "_min_caml_start: # main entry point\n";

Printf.fprintf oc "\tmflr\tr0\n";

Printf.fprintf oc "\tstmw\tr30, -8(r1)\n";

Printf.fprintf oc "\tstw\tr0, 8(r1)\n";

Printf.fprintf oc "\tstwu\tr1, -96(r1)\n";

Printf.fprintf oc "#\tmain program starts\n";

mflr r0

r0 へリンクレジスタの値をmove

stmw r30, -8(r1)

stw r0, 8(r1)

stwu r1, -96(41)

プログラム終了 〜 main へ戻る直前

code:ml

Printf.fprintf oc "#\tmain program ends\n";

(* Printf.fprintf oc "\tmr\tr3, %s\n" regs.(0); *)

Printf.fprintf oc "\tlwz\tr1, 0(r1)\n";

Printf.fprintf oc "\tlwz\tr0, 8(r1)\n";

Printf.fprintf oc "\tmtlr\tr0\n";

Printf.fprintf oc "\tlmw\tr30, -8(r1)\n";

Printf.fprintf oc "\tblr\n"

lwz r1, 0(r1)

lwz r0, 8(r1)

mtlr r0

r0に格納された値をリンクレジスタへmove

lmw r30, -8(r1)

blr

mainへ戻る