Author Archives: Isabekov

A solution without regular expressions

There are many ways for selecting columns in a delimited text. The easiest ones require GNU awk, cut and Perl. Let's consider the following file:

Quick sharing of a single/multiple files in a directory over HTTP protocol will be covered. Let's assume that the file sharing will be done over wlp3s0 Wi-Fi interface and the server's IP address is 192.168.0.24 as shown below:

A draft of the new version of the book "Speech and Language Processing (3rd ed. draft)" by Dan Jurafsky and James H. Martin is available on authors' website. Although it is produced using pdflatex with hyperref, the bookmarks of the table of contents (TOC) have an incorrect hierarchy. However, the …

Sometimes large books or theses may contain many chapters, section and subsections. Reading such PDF documents with the whole table of contents hierarchy shown in the bookmarks panel may be difficult. There is a way to tell PDF viewers to show only a specific level of bookmarks and hide its …

Recursively download a part of a website (all files are downloaded, hierarchy is preserved and links are converted)

There are no tutorials explaining the use of BSCAN_SPARTAN3 primitive on Xilinx FPGAs. It's a very useful feature, which allows to literally establish a PC-to-FPGA link over a JTAG adapter. This primitive is already used in projects such as xc3sprog and Papilio-Loader to program SPI flash memory over JTAG.

BSCAN_SPARTAN3 …

The GNU Debugger (GDB) is a powerful tool to debug binary executables. It can be used to do reverse-engineering as well. Let's debug the following code written by LiveOverflow:

I wanted to write a simple program in AMD64 assembly language which prints "Hello, World!". Here is the code:

Examining data stored in the memory of the program may be interesting to understand low-level mechanism of variable management and type conversions. Let's dump content of an integer bytewise:

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The following setup was used for Basys2 board with an external FTDI-based JTAG adapter. Read the previous posts to get familiar with setup.

Specifying USERCODE

User code register provides bit stream identification and a type of version control. To write a user code into a bit stream in Xilinx ISE, …

In order to program Basys2 board using xc3sprog and FTDI-Based JTAG Adapter, learn positions of the devices in the chain:

UrJTAG is a good low-level tool to learn boundary scan operations and play with EXTEST, INTEST instructions. Assuming that the Basys2 board is connected to a UM232H-based JTAG adapter as described in the previous article, we can test EXTEST and INTEST instructions. Note that depending on package (VQ100, CP132, …

I had a task to check whether OpenOCD can program a Spartan 3 series FPGA by means of FTDI-MPSSE-based JTAG adapter. There wasn't any chip available in my hands, so I had to experiment with existing hardware. I decided to solder the FTDI-based adapter to a Basys2 development board. The …