--- /dev/null
+/***************************************************************************
+ *   Copyright (C) 2010 by Spencer Oliver                                  *
+ *   spen@spen-soft.co.uk                                                  *
+ *                                                                         *
+ *   This program 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 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program 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 this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ ***************************************************************************/
+
+/*
+       parameters:
+       r0 - address in
+       r1 - byte count
+       r2 - mask - result out
+*/
+
+       .text
+       .arm
+
+loop:
+       ldrb r3, [r0], #1
+       and r2, r2, r3
+       subs r1, r1, #1
+       bne loop
+end:
+       bkpt    #0
+
+CRC32XOR:      .word   0x04c11db7
+
+       .end
 
--- /dev/null
+/***************************************************************************
+ *   Copyright (C) 2010 by Spencer Oliver                                  *
+ *   spen@spen-soft.co.uk                                                  *
+ *                                                                         *
+ *   This program 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 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program 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 this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ ***************************************************************************/
+
+/*
+       parameters:
+       r0 - address in
+       r1 - byte count
+       r2 - mask - result out
+*/
+
+       .text
+       .syntax unified
+       .cpu cortex-m0
+       .thumb
+       .thumb_func
+
+       .align  2
+
+loop:
+       ldrb    r3, [r0]
+       adds    r0, #1
+       ands    r2, r2, r3
+       subs    r1, r1, #1
+       bne             loop
+end:
+       bkpt    #0
+
+       .end
 
        uint32_t i;
        uint32_t exit_var = 0;
 
-       /* see contib/loaders/checksum/armv4_5_crc.s for src */
+       /* see contrib/loaders/checksum/armv4_5_crc.s for src */
 
        static const uint32_t arm_crc_code[] = {
                0xE1A02000,             /* mov          r2, r0 */
        uint32_t i;
        uint32_t exit_var = 0;
 
+       /* see contrib/loaders/erase_check/armv4_5_erase_check.s for src */
+
        static const uint32_t check_code[] = {
                /* loop: */
                0xe4d03001,             /* ldrb r3, [r0], #1 */