1 files changed, 80 insertions, 0 deletions
diff --git a/firmware/fx2/common/_startup.a51 b/firmware/fx2/common/_startup.a51
new file mode 100644
index 000000000..30a907857
--- /dev/null
+++ b/firmware/fx2/common/_startup.a51
@@ -0,0 +1,80 @@
+;;; -*- 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