jm + silicon   3

Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35
Amazing reverse engineering.
In a hotel room in Texas, Clive Sinclair had a big problem. He wanted to sell a cheap scientific calculator that would grab the market from expensive calculators such as the popular HP-35. Hewlett-Packard had taken two years, 20 engineers, and a million dollars to design the HP-35, which used 5 complex chips and sold for $395. Sinclair's partnership with calculator manufacturer Bowmar had gone nowhere. Now Texas Instruments offered him an inexpensive calculator chip that could barely do four-function math. Could he use this chip to build a $100 scientific calculator?
Texas Instruments' engineers said this was impossible - their chip only had 3 storage registers, no subroutine calls, and no storage for constants such as π. The ROM storage in the calculator held only 320 instructions, just enough for basic arithmetic. How could they possibly squeeze any scientific functions into this chip?

Fortunately Clive Sinclair, head of Sinclair Radionics, had a secret weapon - programming whiz and math PhD Nigel Searle. In a few days in Texas, they came up with new algorithms and wrote the code for the world's first single-chip scientific calculator, somehow programming sine, cosine, tangent, arcsine, arccos, arctan, log, and exponentiation into the chip. The engineers at Texas Instruments were amazed.

How did they do it? Up until now it's been a mystery. But through reverse engineering, I've determined the exact algorithms and implemented a simulator that runs the calculator's actual code. The reverse-engineered code along with my detailed comments is in the window below.
reversing  reverse-engineering  history  calculators  sinclair  ti  hp  chips  silicon  hacks 
august 2013 by jm
Breakthrough silicon scanning discovers backdoor in military chip [PDF]
Wow, I'd missed this:

This paper is a short summary of the first real world detection of a backdoor in a military grade FPGA. Using an innovative patented technique we were able to detect and analyse in the first documented case of its kind, a backdoor inserted into the Actel/Microsemi ProASIC3 chips for accessing FPGA configuration. The backdoor was
found amongst additional JTAG functionality and exists on the silicon itself, it was not present in any firmware loaded onto the chip. Using Pipeline Emission Analysis (PEA), our pioneered technique, we were able to extract the secret key to activate the backdoor, as well as other security keys such as the AES and the Passkey. This way an attacker can extract all the configuration data from the chip, reprogram crypto and access keys, modify low-level silicon features, access unencrypted configuration bitstream or permanently damage the device. Clearly this
means the device is wide open to intellectual property (IP) theft, fraud, re-programming as well as reverse engineering of the design which allows the introduction of a new backdoor or Trojan. Most concerning, it is
not possible to patch the backdoor in chips already deployed, meaning those using this family of chips have to accept the fact they can be easily compromised or will have to be physically replaced after a redesign of the silicon itself.
chips  hardware  backdoors  security  scanning  pea  jtag  actel  microsemi  silicon  fpga  trojans 
july 2013 by jm
www.Visual6502.org
'working from a single 6502, we exposed the silicon die, photographed its surface at high resolution and also photographed its substrate. Using these two highly detailed aligned photographs, we created vector polygon models of each of the chip's physical components - about 20,000 of them in total for the 6502. These components form circuits in a few simple ways according to how they contact each other, so by intersecting our polygons, we were able to create a complete digital model and transistor-level simulation of the chip. This model is very accurate and can run classic 6502 programs, including Atari games. By rendering our polygons with colors corresponding to their 'high' or 'low' logic state, we can show, visually, exactly how the chip operates: how it reads data and instructions from memory, how its registers and internal busses operate, and how toggling a single input pin (the 'clock') on and off drives the entire chip to step through a program and get things done.' Awesome
6502  emulation  physics  simulation  mos  atari-2600  pet  commodore  c-64  cpu  silicon  from delicious
september 2010 by jm

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