Tag
The article reverse-engineers the Intel 8087's tangent instruction, explaining how it combines CORDIC and polynomial approximation for efficient floating-point calculations in vintage computing.
The article details the reverse-engineering of microcode in Intel's 8087 floating-point chip, focusing on the complex implementation of the FSCALE instruction and the chip's historical role in establishing floating-point standards.
The article describes the process of decoding NEC V20 CPU microcode using high-resolution die photography to improve cycle-accurate emulation in MartyPC, building on prior 8088 microcode work.
The article explains the Early Start memory access technique in Intel's 80386, which hides memory latency by overlapping address generation with the previous instruction's last cycle. It describes the implementation of this technique in the z386 FPGA core, achieving ao486-class performance and a 39% improvement in Doom FPS.
A detailed reverse-engineering analysis of the microcode inside the Intel 8087 floating-point coprocessor, focusing on the FXCH register exchange instruction and the chip's internal architecture.
The article details z386, an open-source FPGA implementation of an 80386 CPU built using the original Intel microcode. It can boot DOS 6/7, run protected-mode programs, and play classic games like Doom, serving as both an educational reconstruction and a usable FPGA CPU.
A blog post detailing the successful disassembly and analysis of the Intel 80386 microcode, revealing 215 instruction entry points and the complex internal architecture.
A detailed blog series documenting the design and implementation of a scientific calculator from scratch using FPGA, covering numerical methods, CPU architecture, microcode, and hardware prototyping.
This project implements a fully functional scientific calculator in hardware using an FPGA, including a custom soft CPU, microcode firmware, and supporting tools. It provides a web-based simulator and open-source Verilog code.
A detailed reverse-engineering analysis of how the Intel 8087 floating-point coprocessor decodes instructions, explaining the interplay between the main CPU and coprocessor, the use of microcode ROM, and the bus interface unit.
A detailed technical analysis of the Intel 8086 processor's arithmetic-logic unit (ALU) control circuitry, explaining how microcode and control signals coordinate to perform 28 different operations.
A detailed examination of the conditional tests used in the Intel 8087 floating-point coprocessor's microcode, part of a reverse-engineering effort to understand its algorithms.
A detailed examination of the Pentium processor's microcode ROM, describing its structure, capacity, and how microcode implements machine instructions at the hardware level.