Tools for working with Texas Instruments COFF and AIS files

aisgen.py

#!/usr/bin/env python
'''Read fully linked  TI COFF file, and generate AIS format file

Commandline parameters
  enable sequential read,
  pll and emifb configuration
  pinmux configuration
  enable checksums

'Eliot Blennerhassett' <eblennerhassett@audioscience.com>
AudioScience Inc. 2011
'''

from struct import pack, unpack
from collections import namedtuple
from ticoff import Coff
#from binascii import crc32
#from numpy import array, fromstring, uint32

class aisgen(object):

    def __init__(self, aisgen_compatible=False):
        self.funcs = {}
        self.crc_enabled = False
        self.aisgen_compatible = aisgen_compatible
        self.verbosity = 0


    def magic(self):
        self.f.write(pack('<I', 0x41504954))


    def enable_crc(self):
        if self.verbosity > 1:
            print 'Enable CRC'
        self.crc_enabled = True
        self.f.write(pack('<I', 0x58535903))


    def disable_crc(self):
        if self.verbosity > 1:
            print 'Disable CRC'
        self.crc_enabled = False
        self.f.write(pack('<I', 0x58535904))


    def validate_crc(self, crc, seek):
        if self.verbosity > 1:
            print 'Validate CRC 0x%08X, seek %d' % (crc, seek)
        self.f.write(pack('<III', 0x58535902, crc, 0x100000000 + seek))


    def section_load(self, s):
        wlen = len(s.data)
        odd = wlen % 4
        write_data = s.data
        npad = 0
        spad = ''
        if odd:
            npad = (4 - odd)
            write_data += ('\0' * npad)
            #write_data += '\x48\x00\x00' # Test to match particular example from AISgen :(
            spad = ' + %d bytes padding' % npad

        command = pack('<I', 0x58535901)
        if self.aisgen_compatible:
        # Generate matching TI AISgen, size in header includes padding
            if self.verbosity > 1:
                print 'Load section 0x%X[0x%06X] %s' % (s.virt_addr, len(write_data), s.name)
            params = pack('<II', s.virt_addr, len(write_data))
        else:
            # Generate according to spec, size in header excludes padding
            if self.verbosity > 1:
                print 'Load section 0x%X[0x%06X]%s %s' % (s.virt_addr, wlen, spad, s.name)
            params = pack('<II', s.virt_addr, wlen)

        crc_data = params + write_data
        self.f.write(command + crc_data)

        if self.crc_enabled and self.crc_calc:
            crc = self.crc_calc(crc_data)
            # Seek backwards, over section data + 2 headers
            seek = -(len(crc_data) + 16)
            self.validate_crc(crc, seek)

    # These values obtained here:
    # http://e2e.ti.com/support/dsp/tms320c6000_high_performance_dsps/f/115/p/118006/423501.aspx
    fill_types = {'8bit' : 0, '16bit' : 1, '32bit' : 2}

    def section_fill(self, addr, nbytes, fill):
        remainder_to_fill_type = [2, 0, 1, 0]

        if self.verbosity > 1:
            print 'Fill section 0x%X[0x%06X] = 0x%X' % (addr, nbytes, fill)
        odd = nbytes % 4
        fill_type = remainder_to_fill_type[odd]

        command = pack('<I', 0x5853590a)
        params = pack('<IIII', addr, nbytes,  fill_type, fill)
        self.f.write(command + params)

        if self.crc_enabled:
            npad = 0
            if odd:
                npad = (4 - odd)
            crc_data = params + chr(fill & 0xFF) * (nbytes + npad)
            crc = self.crc_calc(crc_data)
            seek = -(4 * (5 + 3)) # back over section fill + validate crc commands
            self.validate_crc(crc, seek)


    def section(self, s):
        f = s.fill_value()
        if f is not None:
            self.section_fill(s.virt_addr, len(s.data), f)
        else:
            self.section_load(s)

    def execute_function(self, fname, params):
        if self.verbosity > 1:
            print 'Execute function %s' % fname,
            for p in params:
                print '0x%X' % p,
            print
        fnum, nparams = self.funcs[fname]
        if len(params) != nparams:
            raise ValueError('Expected %d params for %s', nparams, fname)
        fh = (len(params) << 16) + fnum
        self.f.write(pack('<II', 0x5853590D, fh))
        self.f.write(pack('<%dI' % len(params), *params))

    PllAndClockParams = namedtuple('PllAndClockParams',
                    'pllm postdiv plldiv3 plldiv5 plldiv7 ' +
                    'clkmode pll_lock_cnt spi_prescale')

    def pll_and_spi_clock_config(self, c):
        '''expects parameters to be instance of PllAndClockParams'''
        #print c
        param1 = (c.pllm << 24) + (c.postdiv << 16) + (c.plldiv3 << 8) + c.plldiv5
        param2 = (c.clkmode << 24) + (c.plldiv7 << 16) + c.pll_lock_cnt
        self.execute_function('PLL and Clock Configuration', (param1,  param2,  c.spi_prescale))


    EmifbParams = namedtuple('EmifbParams', 'sdcfg sdtim1 sdtim2 sdrfc')

    def emifb_config(self, c):
        '''expects parameters to be instance of EmifbParams'''
        #print c
        self.execute_function('EMIFB SDRAM Configuration', c)

    def pinmux_config(self, c):
        '''expects parameters to be 2 or 3 element tuple
        (index, value [, mask])
        '''
        c = c + (0xFFFFFFFF, ) # default mask if not provided
        self.execute_function('Pinmux Configuration', (c[0], c[2], c[1]))


    def sequential_read(self):
        if self.verbosity > 1:
            print 'Sequential read enable'
        self.f.write(pack('<I', 0x58535963))


    def jump_and_close(self, addr):
        if self.verbosity > 1:
            print 'Jump and close 0x%X' % addr
        self.f.write(pack('<II', 0x58535906, addr))


    def generate(self, filename, coff, options):
        if self.verbosity > 0:
            print 'Generating for %s...' % self.rom,

        load_sections = coff.loadable_sections
        entry_point = coff.entry_point

        with open(filename, 'wb') as self.f:
            self.magic()
            if options.sequential_read:
                self.sequential_read()

            if options.pll_config:
                pll_params = eval('self.PllAndClockParams(%s)' % options.pll_config)
                self.pll_and_spi_clock_config(pll_params)

            if options.emifb_config:
                emifb_params = eval('self.EmifbParams(%s)' % options.emifb_config)
                self.emifb_config(emifb_params)

            for c in options.pinmux_config:
                params = eval('(%s)' % c)
                self.pinmux_config(params)

            if options.enable_crc:
                self.enable_crc()

            for s in load_sections:
                self.section(s)

            self.jump_and_close(entry_point)

class aisgen_d800k001(aisgen):
    '''Instance of aisgen that implements ROM d800k001
    CRC calculation and special functions'''

    def __init__(self):
        aisgen.__init__(self)
        self.rom = 'd800k001'
        self.funcs =  {
            # func name : (id, param count)
            'PLL0 Configuration' : (0, 2),
            'Peripheral Clock Configuration' : (1, 1),
            'EMIFB SDRAM Configuration' : (2, 4),
            'EMIFA SDRAM Configuration' : (3, 4),
            'EMIFA CE Space Configuration' : (4, 4),
            'PLL and Clock Configuration' : (5, 3),
        }

    def _crc_calc_direct(self, data, crc=0):
        '''Reference implementation of CRC
        Process 32 bit words MSB first
        Data is little endian. Very SLOW!'''
        words = fromstring(data, dtype=uint32)
        for word in words:
            bit_no = 31;
            while bit_no >= 0:
                msb_bit = crc & 0x80000000
                crc = ((word >> bit_no) & 0x1) | (crc << 1)
                if msb_bit:
                    crc ^= 0x04C11DB7
                bit_no -= 1

        return crc & 0xFFFFFFFF

    def crc_calc(self, in_str, crc=0):
        '''Generate CRC to match TI AISgen output, from data zero padded to N*4 bytes.
        This is not the same as standard CRC calculation, lacking the augmentation of
        the input data with 32 zero bits.

        Applies to C6747/5/3 devices ROM d800k003,  but not C6748/6/2, see
        http://e2e.ti.com/support/dsp/tms320c6000_high_performance_dsps/f/115/p/119062/426491.aspx
        '''
        nbytes = len(in_str)
        for w in range(0, nbytes, 4):
            # in-place endian reversal to
            # process little endian words MSbyte first
            for b in range(3, -1, -1):
                ofs = w + b
                c = in_str[ofs]
                octet = ord(c)
                for i in range(8):
                    topbit = crc & 0x80000000
                    crc = ((octet >> (7 - i)) & 0x01) | ((crc << 1) & 0xFFFFFFFF)
                    if topbit:
                        crc ^= 0x04C11DB7

        return crc

class aisgen_d800k003(aisgen_d800k001):
    '''Instance of aisgen that implements ROM d800k003
    CRC calculation and special functions'''

    def __init__(self):
        aisgen_d800k001.__init__(self)
        self.rom = 'd800k003'
        self.funcs['Power and Sleep Controller Configuration'] =   (6, 1)
        self.funcs['Pinmux Configuration'] = (7, 3)


roms = {
    'd800k001' : aisgen_d800k001,
    'd800k003' : aisgen_d800k003
}

if __name__ == '__main__':
    from optparse import OptionParser
    from sys import exit

    parser = OptionParser(usage='%prog [options] input.coff output.ais')

    parser.add_option('-c', '--enable-crc', action='store_true',
                        default=False, help='enable per-section CRCs')

    parser.add_option('-r', '--rom', action='store',  choices=roms.keys(), metavar='ROM_VERSION',
                        default='d800k003', help='one of %s' % roms.keys())

    parser.add_option('-s', '--sequential-read', action='store_true',
                        default=False, help='use SPI sequential read')

    parser.add_option('-v', '--verbosity', action='store', type='int',
                        default=1, help='verbosity of output')

    parser.add_option('-b', '--emifb-config', action='store', type='string',
        help='E.g. --emifb-config="sdcfg=0x10620, sdtim1=0x01912a08, sdtim2=0x70080005, sdrfc=0x8000079e"')

    parser.add_option('-p', '--pll-config', action='store', type='string',
        help='E.g. --pll-config="pllm=29, postdiv=1, plldiv3=3, plldiv5=2, plldiv7=5, clkmode=1, pll_lock_cnt=402, spi_prescale=6"')

    parser.add_option('-m', '--pinmux-config', action='append', type='string',
        default=[], help='PINMUX_CONFIG=regnum,value[,optional mask]. May be used more than once\n'+
        'E.g. --pinmux-config=0,0x10011101 -m1,0x1001,0xFFFF')

    options, args = parser.parse_args()

    #
    if args[0][0] == '@':
        fa = []
        with open(args[0][1:]) as f:
            for l in f:
                fa.append(l.strip())
        fa = fa + args[1:]
        options, args = parser.parse_args(args=fa, values=options)

    if len(args) < 2:
        parser.print_help()
        exit()

    coff = Coff(args[0])

    gen = roms[options.rom]()
    gen.verbosity = options.verbosity

    gen.generate(args[1], coff, options)

    if options.verbosity:
        print 'Finished'

aisread.py

#!/usr/bin/env python
"""
Parse AIS file, and optionally generate C array

"Eliot Blennerhassett" <eblennerhassett@audioscience.com>
AudioScience Inc. 2011
"""

import os
import struct
import sys
from optparse import OptionParser

def read(format):
    datalen = struct.calcsize(format)
    data = Input.read(datalen)
    if len(data) != datalen:
        raise EOFError
    ret = struct.unpack(format, data)
    if len(ret) < 2:
        ret = ret[0]
    return ret

def section_load():
    address = read('I')
    size = read('I')
    # data length is rounded up from size to multiple o4
    data = read('%dI' %  ((size + 3) / 4))
    try:
        len(data)
    except TypeError:
        data = [data]

    print '// Section load %#x[%#x]' % (address, size)
    if all([d == data[0] for d in data]):
        print '//   ^ could use Section fill with %#x command' % data[0]
    if gen_h:
        print '%#x, %#x,' % (address, size)
        for i in xrange(len(data)):
            print '0x%08x,' % data[i],
            if not((i + 1) % 8):
                print
        if (i + 1) % 8:
            print


def section_fill():
    address = read('I')
    size = read('I')
    type = read('I')
    pattern = read('I')
    print '// Section Fill type %d %#x[%#x] = %#x' % (type, address, size, pattern)
    if gen_h:
        print '%#x, %#x, %#x, %#x' % (address, size, type, pattern)


def boot_table():
    type = read('I')
    address = read('I')
    data = read('I')
    sleep = read('I')
    print '// Boot table type %d *%#x = %#x, sleep %d' % (type, address, data, sleep )
    if gen_h:
        print '%#x, %#x, %#x, %#x' % (type, address, data, sleep)


# This function list comes from sprab1b.pdf 'Using the TMS320C6747/45/43 Bootloader'
funcs = {
    0 : ('PLL0 Configuration', 2),
    1 : ('Peripheral Clock Configuration', 1),
    2 : ('EMIFB SDRAM Configuration', 4),
    3 : ('EMIFA SDRAM Configuration', 4),
    4 : ('EMIFA CE Space Configuration', 4),
    5 : ('PLL and Clock Configuration', 3),
    6 : ('Power and Sleep Controller Configuration', 1),
    7 : ('Pinmux Configuration', 3),
}


def function_execute():
    arg = read('I')
    func = arg & 0xFFFF
    ac = (arg & 0xFFFF0000) >> 16
    try:
        fn, ac1 = funcs[func]
    except KeyError:
        fn = 'Unkown %#x' % func
        ac1 = 0

    assert ac == ac1, 'Arg count mismatch %d %d' % (ac, ac1)

    print '// Function %d : %s(' % (func, fn),
    args = []
    for i in range(ac):
        args.append(read('I'))
        print '%#x, ' % args[i],
    print ')'
    if gen_h:
        print '%#x,' % arg,
        for i in range(ac):
            print '%#x, ' % args[i],
        print


def jump_and_close():
    address = read('I')
    print '// Close and jump to %#x' % address
    if gen_h:
        print '%#x,' % address


def jump(op):
    address = read('I')
    print '// Jump to %#x' % address
    if gen_h:
        print '%#x,' % address


def validate_crc():
    crc = read('I')
    seek = read('I')
    print '// Validate CRC %#x, seek %x' % (crc, seek)
    if gen_h:
        print '%#x, %#x,' % (crc, seek)


def enable_crc():
    print '// Enable CRC'


def disable_crc():
    print '// Enable CRC'


def sequential_read():
    print '// Sequential read enable'


opcodes = {
    0x58535901 : section_load,
    0x58535902 : validate_crc,
    0x58535903 : enable_crc,
    0x58535904 : disable_crc,
    0x58535905 : jump,
    0x58535906 : jump_and_close,
    0x58535907 : boot_table,
    0x5853590a : section_fill,
    0x5853590D : function_execute,
    0x58535963 : sequential_read,
}


parser = OptionParser()
parser.add_option("-g", "--generate-header",
                  action="store_true", dest="gen_h", default=False,
                  help="generate full header file on stdout")

(options, args) = parser.parse_args()

fname = args[0]
fsize = os.path.getsize(fname)

gen_h = options.gen_h

if gen_h:
    print '''// Generated from %s
#include <stdint.h>
uint32_t ais_array[] = {'''


with open (fname, 'rb') as Input:
    magic = read('I')
    if not (magic == 0x41504954):
        sys.exit('Incorrect magic, not an AIS file?')

    print '// AIS magic ID'
    if gen_h:
        print '%#x,' %  magic

    while True:
        try:
            opcode = read('I')
        except EOFError:
            break
        try:
            command = opcodes[opcode]
        except KeyError:
            print 'unknown opcode %#x' % opcode

        if gen_h:
            print '%#x,' % opcode,

        command()
    if gen_h:
        print '};'

    assert Input.tell() == fsize, 'file  not consumed?'

pinsetup.py

#!/usr/bin/env python
'''Read TI pinmux data files, and pinmux config file
and generate pinmux register values, and comments.

Requires mux[1-5].txt from TI pinsetup utility OMAP-L1x7_C6747-5-3_pinsetup

There are 20 pinmux registers, each with 8 4-bit fields

"Eliot Blennnerhassett" <eblennerhassett@audioscience.com>
'''
from sys import exit

def read_pin_data():
    '''Read pin data into 2 dictionaries.
    pd key is pin function name, value is (reg_idx, field_idx, field value, ?)
    pf  key (reg_idx, field_idx), value is [list of pin names]

    pin data files contain lines like
        AXR0[0],10,1,1,830
        pin_func_name, reg_idx, field_idx, field_value, ??
        not sure what the last value represents?
    '''
    pd = {} # setups per pin function
    pf = {} # pin functions per register field
    for fi in range(1, 6):
        fn = 'mux%d.txt' % fi
        with open(fn) as f:
            for l in f:
                t = l.strip().split(',')
                if len(l) < 5:
                    continue
                pin_name = t[0]
                p = tuple([int(s) for s in t[1:]])
                pi = p[0:2]
                # ((reg_idx, field_idx) : ['pin_name', ...]
                if pf.has_key(pi):
                    pf[pi].append(pin_name)
                else:
                    pf[pi] = [pin_name]

                # 'pin_name' : (reg_idx, field_idx, field value, ?)
                pd[pin_name] = p
    return pd, pf


def read_pin_config(fn, pd):
    '''read pin config from file named fn, and add pinmux setup data from pd
    pin config is a list of pin function names, one per line
    '''
    pins = []
    with open(fn) as f:
        for l in f:
            n = l.strip()
            if not len(n):
                continue
            ps = pd[n]
            pins.append((n, ps))
    return pins


def print_alpha_pinlist(pins):
    '''print list of pin names in alphabetical order'''
    pins.sort() # pin name order
    print '/*\nDefined pins:',
    wrap = 0
    for pin in pins:
        if wrap > 70:
            print
            wrap = 0
        print pin[0],
        wrap += len(pin[0]) + 1
    print '\n*/'

def print_muxfield_pinlist(pins):
    '''print list of pin names grouped by mux field value'''
    pins.sort(key=lambda p : (p[1][2], p[1][0], p[1][1]))
    prev_mux = None
    print '/*\nPins by mux field setting:',
    for pin in pins:
        mux = pin[1][2]
        if mux != prev_mux:
            print '\n\nMUX%d Pins:' % mux
            prev_mux = mux
            wrap = 0
        if wrap > 70:
            print
            wrap = 0
        print pin[0],
        wrap += len(pin[0]) + 1
    print '\n*/'


def print_pinmux_pinlist(pins):
    '''print list of pin names grouped by pinmux register'''
    pins.sort(key=lambda p : (p[1][0], p[1][1]))
    print '/* Pins by pinmux register'
    prev_regidx = None
    for pin in pins:
        regidx = pin[1][0]
        if regidx != prev_regidx:
            print '\npinmux[%d] pins' % regidx
            prev_regidx = regidx
        print pin[0],
    print '\n*/'


def calculate_pinmux_values(pins, pd, pf):
    '''convert the selected pin data into appropriate bitfields
    in registers
    '''
    regs = [0] * 20
    error = False
    for pin in pins:
        ps = pin[1]
        reg = ps[0]
        field_ofs = ps[1] * 4
        field_mask = 0xF << field_ofs
        field_val = ps[2] << field_ofs

        if (regs[reg] & field_mask):
            fv = (regs[reg] & field_mask) >> field_ofs
            # find which pin already assigned to the field
            current = (reg, ps[1], fv)
            shared = pf[ps[0:2]]
            for name in shared:
                id = pd[name][0:3]
                if current == id:
                    break;

            print 'Conflict setting %s : pinmux[%d][%d] already set to %s' % (pin[0], reg, ps[1], name)
            error = True
        else:
            regs[reg] = regs[reg] | field_val;

    if error:
        exit(1)

    return regs


formats = {
    'aisgen' : '--pinmux-config=%d,0x%08X',
    'array' : '\t/* %d */ 0x%08X,',
    'define' : '#define PINMUX%d_VALUE 0x%08X',
}

def print_pinmux_values(format, regs):
    '''print the pinmux register value list
    formatted for various uses
    '''
    fs = formats[format]
    if format == 'array':
        print 'unsigned int pinmux_values = {'
    for i in range(len(regs)):
        print fs % (i, regs[i])
    if format == 'array':
        print '};'


def print_known_pins(pf):
    pl = list( pf.iteritems())
    pl.sort(key=lambda p : (p[0][0], p[0][1]))
    for p in pl:
        print 'pinmux %s selects %s' % p

if __name__ == '__main__':
    from optparse import OptionParser

    parser = OptionParser(usage='%prog [options] input.pin')

    parser.add_option('-a', '--print-alpha', action='store_true',
                        default=False, help='Print alphabetical pinlist comment')

    parser.add_option('-m', '--print-muxfield', action='store_true',
                        default=False, help='Print pinlist by mux value comment')

    parser.add_option('-r', '--print-register', action='store_true',
                        default=False, help='Print pinlist by register comment')

    parser.add_option('-f', '--format', action='store',  choices=formats.keys(),
                        default='define', help='one of %s' % formats.keys())

    parser.add_option('-p', '--print-known', action='store_true',
                        default=False, help='print known pins')

    options, args = parser.parse_args()

    pd, pf = read_pin_data()

    if options.print_known:
        print_known_pins(pf)
        exit(0)

    pins = read_pin_config(args[0], pd)

    regs = calculate_pinmux_values(pins, pd, pf)

    if options.print_alpha:
        print_alpha_pinlist(pins)
    if options.print_muxfield:
        print_muxfield_pinlist(pins)
    if options.print_register:
        print_pinmux_pinlist(pins)

    print_pinmux_values(options.format, regs)

ticoff.py

#!/usr/bin/env python
"""
Read TI COFF file into a python object

"Eliot Blennerhassett" <eblennerhassett@audioscience.com>
AudioScience Inc. 2011
"""
from __future__ import print_function

from builtins import bytes, object, range
from array import array
from collections import namedtuple
from optparse import OptionParser
from struct import unpack, calcsize

def read_struct(file, format):
    '''read struct data formatted according to format'''
    datalen = calcsize(format)
    data = file.read(datalen)
    if len(data) != datalen:
        raise EOFError
    ret = unpack(format, data)
    if len(ret) < 2:
        ret = ret[0]
    return ret


def read_cstr(file):
    '''read zero terminated c string from file'''
    output = ""
    while True:
        char = file.read(1)
        if len(char) == 0:
            raise RuntimeError ("EOF while reading cstr")
        char = chr(bytes(char)[0])
        if char == '\0':
            break
        output += char
    return output

# From spraao8.pdf table 7
class Section(namedtuple('Section',
    'name, virt_size, virt_addr, raw_data_size, raw_data_ptr, relocation_ptr,' +
    'linenum_ptr, linenum_count, reloc_count, flags, reserved, mem_page, data')):

    __slots__ = () # prevent creation of instance dictionaries
    section_fmt = '<8s9L2H'
    section_flags = [
        (0x00000001, 'STYP_DSECT'), (0x00000002, 'STYP_NOLOAD'),
        (0x00000004, 'STYP_GROUPED'), (0x00000008, 'STYP_PAD'),
        (0x00000010, 'STYP_COPY'), (0x00000020, 'STYP_TEXT'),
        (0x00000040, 'STYP_DATA'), (0x00000080, 'STYP_BSS'),
        (0x00000100, 'STYP_100'), (0x00000200, 'STYP_200'),
        (0x00000200, 'STYP_400'), (0x00000800, 'STYP_800'),
        (0x00001000, 'STYP_BLOCK'), (0x00002000, 'STYP_PASS'),
        (0x00004000, 'STYP_CLINK'),(0x00008000, 'STYP_VECTOR'),
        (0x00010000, 'STYP_PADDED'),
    ]

    @property
    def is_zero_filled(self):
        return (self.data is not None) and not any([d != '\0' for d in self.data])

    def fill_value(self):
        if self.data is  None:
            return None

        if len(self.data) % 4:
            return None # only handle 32 bit fill

        a = array('I', self.data)
        if all([d == a[0] for d in a]):
            return a[0]
        else:
            return None

    @property
    def is_loadable(self):
        return not(self.flags & 0x00000010 or self.data is None)

    def __str__(self):
        s = 'Section %s' % self.name
        if self.flags:
            s += ' Flags ='
            for f in Section.section_flags:
                if self.flags & f[0]:
                    s = s + ' ' + f[1]
        for fv in self._asdict().items():
            if fv[0] == 'data' or fv[0] == 'name': continue
            s = s + '\n\t%s = 0x%X' % fv
        return s

class Coff(object):
    Header = namedtuple('Header',
        'machine_type, section_count, time_date, symbol_table_ptr, ' +
        'symbol_count, optional_header_size, flags, target_id')
    header_fmt = '<2H3L3H'

    OptionalHeader = namedtuple('OptionalHeader',
        'magic, version, exe_size, init_data_size, uninit_data_size, entry_point, exe_start, init_start')
    optheader_fmt = '<2H6L'

    def __init__(self, filename=None):
        self.header = None
        self.optheader = None
        self.sections = []
        if filename is not None:
            self.from_file(filename)

    def from_file(self, name):
        with open(name, 'rb') as f:
            self.from_stream(f)

    def from_stream(self, f):
        self.header = self.Header(*read_struct(f, self.header_fmt))
        self.optheader = self.OptionalHeader(*read_struct(f, self.optheader_fmt))
        self.sections = []
        for i in range(self.header.section_count):
            section = Section(*read_struct(f, Section.section_fmt), data=None)
            section = section._replace(name=self.symname(f, section.name))
            if section.raw_data_ptr and section.raw_data_size:
                here = f.tell()
                f.seek(section.raw_data_ptr)
                # TODO: `2 *` is hard coded to handle the 2-bytes per
                #       address scenario.  This should obviously be
                #       detected somehow, unless it is always correct.
                data = bytes(f.read(2 * section.raw_data_size))
                f.seek(here)
                section = section._replace(data=data)
            self.sections.append(section)

        self.entry_point = self.optheader.entry_point
        self.sections.sort(key=lambda s: s.virt_addr)

    @property
    def loadable_sections(self):
        return [s for s in self.sections if s.is_loadable]

    def string_table_entry (self, f, offset):
        here = f.tell()
        seek = self.header.symbol_table_ptr + self.header.symbol_count * 18 + offset
        f.seek(seek)
        s = read_cstr(f)
        f.seek(here)
        return s

    def symname(self, f, value):
        parts = unpack("<2L", value)
        if parts[0] == 0:
            return self.string_table_entry(f, parts[1])
        else:
            return str(value.decode('ascii').rstrip('\0'))

    def __str__(self):
        s = 'TI coff file'
        if self.header is not None:
            for fv in self.header._asdict().items():
                s = s + '\n\t%s = 0x%X' % fv
        if self.optheader is not None:
            s += '\nOptional Header'
            for fv in self.optheader._asdict().items():
                s = s + '\n\t%s = 0x%X' % fv
        return s

if __name__ == '__main__':
    parser = OptionParser()
    parser.add_option("-d", "--dump_data",
                      action="store_true", dest="dump", default=False,
                      help="dump section data")

    options, args = parser.parse_args()

    c = Coff(args[0])
    print(c)

    for section in c.sections:
        print(section)
        if section.data is not None and options.dump:
            print(repr(section))