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Inspired by this thread.
Since mbed's startup code is quite standard, it's possible to parse it with a little work. I made a Python script which looks for the scatter region table and calculates some values from it.
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# script to print memory usage stats for binaries produced by mbed online compiler
# Version 1.0, 2010-01-23
# Author: Igor Skochinsky
import sys, struct
RAM_START = 0x10000000
RAM_SIZE = 0x00008000 # 32K
FLASH_SIZE = 0x00080000 # 512K
# read a 4-byte dword (little-endian) from file
def getDword(f, off):
f.seek(off)
data = f.read(4)
if len(data) != 4:
print "Trying to read ouside the file!"
return 0
return struct.unpack("<I", data)[0]
class RegionEntry:
def __init__(self, f, off):
f.seek(off)
data = f.read(4*4)
if len(data) != 4*4:
print "Trying to read ouside the file!"
return
values = struct.unpack("<IIII", data)
self.source = values[0]
self.dest = values[1]
self.size = values[2]
self.func = values[3]
def show_stats(f):
sp = getDword(f, 0)
if sp != RAM_START + RAM_SIZE:
print "Warning: stack pointer (%08X) is different from expected value (%08X)" % (sp, RAM_START + RAM_SIZE)
entry = getDword(f, 4)
print "Entry point address: %08X" % entry
if entry & 1 != 1:
print "Doesn't look like a Cortex-M3 binary"
return
entry &= ~1
f.seek(entry)
startup = f.read(8)
# ldr r0, =HWInit
# blx r0
# ldr r0, =__main
# bx r0
if startup != "\x06\x48\x80\x47\x06\x48\x00\x47":
print "Wrong startup code, probably not an mbed 1768 binary"
return
__main = getDword(f, entry + 0x20) & ~1
f.seek(__main)
if f.read(4) != "\x00\xF0\x02\xF8":
print "Wrong startup code, probably not an mbed 1768 binary"
return
#fetch scatter region table pointers
tblptrs = __main+0x34
tblstart = getDword(f, tblptrs) + tblptrs
tblend = getDword(f, tblptrs+4) + tblptrs
tblsize = tblend - tblstart
tblentries = tblsize / 16
if tblsize % 16 != 0 or tblentries == 0 or tblentries > 2:
print "Wrong size of scatter region table (%d entries)" % tblentries
return
entry1 = RegionEntry(f, tblstart)
# first entry sets up RW data
# so its src address will be code + RO data size
code_rodata = entry1.source
# size will be the size of RW data
rwdata = entry1.size
if tblentries == 2:
# second entry sets up ZI data
# its "source" will be the total flash size, but we'll just use the file size
entry2 = RegionEntry(f, tblstart+16)
zidata = entry2.size
else:
# no ZI data
zidata = 0
usedram = rwdata + zidata
f.seek(0, 2)
usedflash = f.tell()
print "Code + RO data = %-7d (0x%05x)" % (code_rodata, code_rodata)
print "RW data = %-7d (0x%05x)" % (rwdata, rwdata)
print "ZI data = %-7d (0x%05x)" % (zidata, zidata)
print "Used flash = %-7d (0x%05x)" % (usedflash, usedflash)
print "Free flash = %-7d (0x%05x)" % (FLASH_SIZE - usedflash, FLASH_SIZE - usedflash)
print "Used RAM = %-7d (0x%05x)" % (usedram, usedram)
print "Free RAM = %-7d (0x%05x)" % (RAM_SIZE - usedram, RAM_SIZE - usedram)
print "mbed 1768 binary stats script 1.0"
if len(sys.argv) >= 2:
inf = open(sys.argv[1],"rb")
show_stats(inf)
else:
print "Usage: binstats.py file.bin"
Save it as binstats.py and pass the binary filename as the parameter. If you need to install it, get Python 2.x, not 3.x.
Please note that the reported sizes are before any C/C++ startup code is executed, so any RAM used by CRT (e.g. malloc structures) or global objects is not included. Also, the stack occupies the top of the RAM and overwriting it is not a good idea.
Example stats for some programs:
FFT.bin:
Entry point address: 00000215
Code + RO data = 43568 (0x0aa30)
RW data = 240 (0x000f0)
ZI data = 380 (0x0017c)
Used flash = 43808 (0x0ab20)
Free flash = 480480 (0x754e0)
Used RAM = 620 (0x0026c)
Free RAM = 32148 (0x07d94)
DOGLCDDemo.bin:
Entry point address: 00000255
Code + RO data = 36128 (0x08d20)
RW data = 2528 (0x009e0)
ZI data = 1720 (0x006b8)
Used flash = 36616 (0x08f08)
Free flash = 487672 (0x770f8)
Used RAM = 4248 (0x01098)
Free RAM = 28520 (0x06f68)
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Hi Igor
I compiled the EthernetTester from this notebook and ran the script with the following outcome:
mbed 1768 binary stats script 1.0
Entry point address: 00000261
Wrong size of scatter region table (3 entries)
Is this due to two libraries being linked (mbed and lwip)?
Thanks
Daniel