view arm7dis/README @ 264:e4a596bbb2bf

dsample-fw-disasm: ARMIO functions located
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 18 Jan 2018 05:39:53 +0000
parents c883e60df239
children
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The present package is a basic standalone disassembler for the ARMv4T
instruction set implemented on the ARM7TDMI CPU core, commonly used in classic
cellular phone baseband processors.  The armdis utility interprets an arbitrary
raw binary image (i.e., one being reverse-engineered) as 32-bit ARM
instructions; thumbdis interprets the same image as 16-bit Thumb instructions.

The form in which the disassembly output is presented is a look-and-feel copycat
of GNU objdump: armdis is meant to replace

objdump -b binary -m arm -EL -M reg-names-std -D unknown-firmware.bin

and thumbdis is meant to replace

objdump -b binary -m arm -EL -M reg-names-std -M force-thumb -D unknown-fw.bin

Aside from sparing the operator from having to remember all those options
every single time, and aside from being an independent from-scratch
implementation (lean and mean, only knows how to disassemble those instructions
which are meaningful on ARM7TDMI), these tools have one other feature which
partly prompted me to write them: whenever *dis disassembles a PC-relative
ldr instruction, it shows the value pulled from the literal pool on that ldr
line.  In the reverse engineering jobs I've had to do, it has been a very
valuable feature for me.

Happy hacking,
Spacefalcon the Outlaw