Subversion Repositories gecko3

;;; -*- asm -*-

;;;

;;; Copyright 2003,2004 Free Software Foundation, Inc.

;;;

;;; This file is part of GNU Radio

;;;

;;; GNU Radio 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.

;;;

;;; GNU Radio 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.

;;;

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

;;; along with GNU Radio; see the file COPYING.  If not, write to

;;; the Free Software Foundation, Inc., 51 Franklin Street,

;;; Boston, MA 02110-1301, USA.

;;; The default external memory initialization provided by sdcc is not

;;; appropriate to the FX2.  This is derived from the sdcc code, but uses

;;; the FX2 specific _MPAGE sfr.

        ;; .area XISEG   (XDATA)  ; the initialized external data area

        ;; .area XINIT   (CODE)   ; the code space consts to init XISEG

        .area XSEG    (XDATA)     ; zero initialized xdata

        .area USBDESCSEG (XDATA)  ; usb descriptors

        .area CSEG    (CODE)

        ;; sfr that sets upper address byte of MOVX using @r0 or @r1

        _MPAGE  =       0x0092

__sdcc_external_startup::

        ;; This system is now compiled with the --no-xinit-opt

        ;; which means that any initialized XDATA is handled

        ;; inline by code in the GSINIT segs emitted for each file.

        ;;

        ;; We zero XSEG and all of the internal ram to ensure

        ;; a known good state for uninitialized variables.

;       _mcs51_genRAMCLEAR() start

        mov     r0,#l_XSEG

        mov     a,r0

        orl     a,#(l_XSEG >> 8)

        jz      00002$

        mov     r1,#((l_XSEG + 255) >> 8)

        mov     dptr,#s_XSEG

        clr     a

00001$: movx    @dptr,a

        inc     dptr

        djnz    r0,00001$

        djnz    r1,00001$

        ;; We're about to clear internal memory.  This will overwrite

        ;; the stack which contains our return address.

        ;; Pop our return address into DPH, DPL

00002$: pop     dph

        pop     dpl

        ;; R0 and A contain 0.  This loop will execute 256 times.

        ;;

        ;; FWIW the first iteration writes direct address 0x00,

        ;; which is the location of r0.  We get lucky, we're

        ;; writing the correct value (0)

00003$: mov     @r0,a

        djnz    r0,00003$

        push    dpl             ; restore our return address

        push    dph

        mov     dpl,#0          ; indicate that data init is still required

        ret