#!/bin/bash
#set -x
# Copyright (C) 2011 by Jonathan Appavoo, Boston University
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

typeset -r IMGSIZE=65536
typeset -r NMIVECOFF=0xFFFA
typeset -r RESETVECOFF=0xFFFC
typeset -r IRQVECOFF=0xFFFE

function create
{
   file=$1

   if [[ $file = '-h' ]]; then
echo "USAGE: create [file]"
      echo " creates an empty image if no file is specified it"
      echo " will be written to standard out. "
      echo " eg. ./img create foo.img"
      echo " will create a new empty 6502 memory image file filled with"
      echo " 0 byte values"
      return -1
   fi

if [[ -z $file ]]; then file=/dev/stdout; fi

dd if=/dev/zero of=$file bs=1 count=$IMGSIZE 2>/dev/null
 
   return 0
}

function load
{
   imgfile=$1
   offset=$(printf %d $2)

   if [[ -z $imgfile || $imgfile = '-h' ]]; then
echo "USAGE: load <imgfile> [offset]"
     echo " loads ascii stream of hex numbers (2 hex digit pairs)"
     echo " from standard in into image file at offset"
     echo " default offset is 0"
     echo " eg. echo '01deadbeef' | ./img load foo.img"
     echo " will load the first five bytes of the foo.img file with byte"
     echo " values of 01deadbeef"
     echo " and echo '01deadbeef' | ./img load foo.img 0x1000"
     echo " would load the same file values at offset 0x1000"
     echo " NOTE you can use the dump command to confirm: "
     echo " eg. img dump foo.img 0x1000 5"
     return -1
   fi

if [[ ! -a $imgfile ]]; then
create $imgfile
   fi

if [[ -z $offset ]]; then
offset=0
   fi
perl -e 'print pack "H*",<STDIN>' | dd of=$imgfile bs=1 seek=$offset conv=notrunc 2>/dev/null

   return 0
}


function dump
{
   file=$1
   offset=$(printf %d $2)
   len=$3

   if [[ -z $file || $file = '-h' ]]; then
echo "USAGE: dump <file> [offset] [len]"
      echo " produces an ascii dump of the contents of an image file"
      echo " if offset is specified then dump will start at offset (default is 0)"
      echo " if len is specified then only len bytes will be dumped (default is to the end of file)"
      return -1
   fi

if [[ ! -a $file ]]; then
echo "ERROR: must specify file"
       return -1
   fi
if [[ -z $offset ]]; then offset=0; fi
if [[ -n $len ]]; then len="-n $len"; fi

hexdump -C -s $offset $len $file
    
   return 0
}

setvec()
{
  addr=$1
  file=$2
  value=$3



  if [[ -z $value ]]; then
dump $file $addr 2
  else
ll=${value##0x??}
    hh=${value%%??}
    hh=${hh##0x}
    echo -n "${ll}${hh}" | load $file $addr
   fi
return 0
}

function resetvec
{
  file=$1
  value=$2

  if [[ -z $file || $file = '-h' ]]; then
echo "ERROR: must specify image file"
     echo "USAGE: resetvec <file> [0xHHLL]"
     echo " dumps or sets the resetvector in the image file"
     echo " value must be specified as a 0x prefixed hex value with HH the page address and LL the offset"
     return -1
  fi
setvec $RESETVECOFF $file $value
  return $?
}

function nmivec
{
  file=$1
  value=$2

  if [[ -z $file || $file = '-h' ]]; then
echo "ERROR: must specify image file"
     echo "USAGE: nmivec <file> [0xHHLL]"
     echo " dumps or sets the resetvector in the image file"
     echo " value must be specified as a 0x prefixed hex value with HH the page address and LL the offset"
     return -1
  fi
setvec $NMIVECOFF $file $value
  return 0
}

function irqvec
{
  file=$1
  value=$2

  if [[ -z $file || $file = '-h' ]]; then
echo "ERROR: must specify image file"
     echo "USAGE: irqvec <file> [0xHHLL]"
     echo " dumps or sets the resetvector in the image file"
     echo " value must be specified as a 0x prefixed hex value with HH the page address and LL the offset"
     return -1
  fi
setvec $IRQVECOFF $file $value
  return 0
}

usage()
{
    echo "USAGE: ${0##*/} func args" >&2
    grep '^function' $0
    echo "for each func use '-h' to print its usage: eg. ${0##*/} dump -h"
    echo "will print the usage for the dump command"
}

processargs()
{
  if [[ $# == 0 || $1 = '-h' ]]
  then
usage
    exit -1
  fi

dofunc=$1
}

processargs "$@"
shift

$dofunc "$@"

exit $?