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/* Copyright (C) 2001, 2002, 2011 Free Software Foundation, Inc.

   Contributed by Hans-Peter Nilsson 

This file is free software; you can redistribute it and/or modify it

under the terms of the GNU General Public License as published by the

Free Software Foundation; either version 3, or (at your option) any

later version.

This file is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

General Public License for more details.

Under Section 7 of GPL version 3, you are granted additional

permissions described in the GCC Runtime Library Exception, version

3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and

a copy of the GCC Runtime Library Exception along with this program;

see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

.  */

% This is the crt0 equivalent for mmix-knuth-mmixware, for setting up

% things for compiler-generated assembly-code and for setting up things

% between where the simulator calls and main, and shutting things down on

% the way back.  There's an actual crt0.o elsewhere, but that's a dummy.

% This file and the GCC output are supposed to be *reasonably*

% mmixal-compatible to enable people to re-use output with Knuth's mmixal.

% However, forward references are used more freely: we are using the

% binutils tools.  Users of mmixal beware; you will sometimes have to

% re-order things or use temporary variables.

% Users of mmixal will want to set up 8H and 9H to be .text and .data

% respectively, so the compiler can switch between them pretending they're

% segments.

% This little treasure is here so the 32 lowest address bits of user data

% will not be zero.  Because of truncation, that would cause testcase

% gcc.c-torture/execute/980701-1.c to incorrectly fail.

        .data   ! mmixal:= 8H LOC Data_Segment

        .p2align 3

        LOC @+(8-@)@7

        OCTA 2009

        .text   ! mmixal:= 9H LOC 8B; LOC #100

        .global Main

% The __Stack_start symbol is provided by the link script.

stackpp OCTA __Stack_start

% "Main" is the magic symbol the simulator jumps to.  We want to go

% on to "main".

% We need to set rG explicitly to avoid hard-to-debug situations.

Main    SETL    $255,32

        PUT     rG,$255

% Initialize the stack pointer.  It is supposedly made a global

% zero-initialized (allowed to change) register in crtn.S; we use the

% explicit number.

        GETA    $255,stackpp

        LDOU    $254,$255,0

% Make sure we get more than one mem, to simplify counting cycles.

        LDBU    $255,$1,0

        LDBU    $255,$1,1

        PUSHJ   $2,_init

#ifdef __MMIX_ABI_GNU__

% Copy argc and argv from their initial position to argument registers

% where necessary.

        SET     $231,$0

        SET     $232,$1

#else

% For the mmixware ABI, we need to move arguments.  The return value will

% appear in $0.

        SET     $2,$1

        SET     $1,$0

#endif

        PUSHJ   $0,main

        JMP     exit

% Provide the first part of _init and _fini.  Save the return address on the

% register stack.  We eventually ignore the return address of these

% PUSHJ:s, so it doesn't matter that whether .init and .fini code calls

% functions or where they store rJ.  We shouldn't get there, so die

% (TRAP Halt) if that happens.

        .section .init,"ax",@progbits

        .global _init

_init:

        GET     $0,:rJ

        PUSHJ   $1,0F

        SETL    $255,255

        TRAP    0,0,0

0H      IS      @

% Register _fini to be executed as the last atexit function.

#ifdef __MMIX_ABI_GNU__

        GETA    $231,_fini

#else

        GETA    $1,_fini

#endif

        PUSHJ   $0,atexit

        .section .fini,"ax",@progbits

        .global _fini

_fini:

        GET     $0,:rJ

        PUSHJ   $1,0F

        SETL    $255,255

        TRAP    0,0,0

0H      IS      @