(*
    BSD 2-Clause License

    Copyright (c) 2019-2020, Anton Krotov
    All rights reserved.
*)

MODULE API;

IMPORT SYSTEM;


CONST

    eol* = 0AX;

    BIT_DEPTH* = 32;

    RTLD_LAZY = 1;


TYPE

    SOFINI = PROCEDURE;


VAR

    MainParam*, libc*: INTEGER;

    dlopen*       : PROCEDURE [linux] (filename, flag: INTEGER): INTEGER;
    dlsym*        : PROCEDURE [linux] (handle, symbol: INTEGER): INTEGER;

    exit*,
    exit_thread*  : PROCEDURE [linux] (code: INTEGER);
    puts          : PROCEDURE [linux] (pStr: INTEGER);
    malloc        : PROCEDURE [linux] (size: INTEGER): INTEGER;
    free          : PROCEDURE [linux] (ptr: INTEGER);

    fini: SOFINI;


PROCEDURE DebugMsg* (lpText, lpCaption: INTEGER);
BEGIN
    puts(lpCaption);
    puts(lpText)
END DebugMsg;


PROCEDURE _NEW* (size: INTEGER): INTEGER;
VAR
    res, ptr, words: INTEGER;

BEGIN
    res := malloc(size);
    IF res # 0 THEN
        ptr := res;
        words := size DIV SYSTEM.SIZE(INTEGER);
        WHILE words > 0 DO
            SYSTEM.PUT(ptr, 0);
            INC(ptr, SYSTEM.SIZE(INTEGER));
            DEC(words)
        END
    END

    RETURN res
END _NEW;


PROCEDURE _DISPOSE* (p: INTEGER): INTEGER;
BEGIN
    free(p)
    RETURN 0
END _DISPOSE;


PROCEDURE GetSym (lib: INTEGER; name: ARRAY OF CHAR; VarAdr: INTEGER);
VAR
    sym: INTEGER;

BEGIN
    sym := dlsym(lib, SYSTEM.ADR(name[0]));
    ASSERT(sym # 0);
    SYSTEM.PUT(VarAdr, sym)
END GetSym;


PROCEDURE init* (sp, code: INTEGER);
BEGIN
    fini := NIL;
    SYSTEM.GET(code - 1000H - SYSTEM.SIZE(INTEGER) * 2, dlopen);
    SYSTEM.GET(code - 1000H - SYSTEM.SIZE(INTEGER),     dlsym);
    MainParam := sp;

    libc := dlopen(SYSTEM.SADR("libc.so.6"), RTLD_LAZY);
    GetSym(libc, "exit", SYSTEM.ADR(exit_thread));
    exit := exit_thread;
    GetSym(libc, "puts", SYSTEM.ADR(puts));
    GetSym(libc, "malloc", SYSTEM.ADR(malloc));
    GetSym(libc, "free", SYSTEM.ADR(free));
END init;


PROCEDURE dllentry* (hinstDLL, fdwReason, lpvReserved: INTEGER): INTEGER;
    RETURN 0
END dllentry;


PROCEDURE sofinit*;
BEGIN
    IF fini # NIL THEN
        fini
    END
END sofinit;


PROCEDURE SetFini* (ProcFini: SOFINI);
BEGIN
    fini := ProcFini
END SetFini;


END API.