Microprocessor architecture development is a long and complicated process. The use of modern advanced software tools helps to accelerate the development process and increases the efficiency of the produced processor. This paper presents basic software tools and their quality improvements. Toolchain development is performed in parallel with the development of the architecture. There are open source solutions, such as the GNU Compiler Collection or LLVM, enabling the rapid prototyping of a compiler for the new architecture. But for the effective use of the architectural features more complex tools like Universal Translating Library are used. This library contains advanced algorithms for analysis and optimization, as well as a mechanism for their integration with any technological chain like GNU or LLVM. Before development of microprocessor design is completed functional simulator is used for testing and debugging of other software components like operating system or applications. Simulator plays the role of the reference model of the microprocessor. The simulator execution time is critical for development so most heavy parts should be optimized. In this paper it is proposed a flag computation method which is two times faster than the popular method of table based flags computation. In the segment of embedded operating systems compact real-time OS are widely used. These OS are linked with the user applications. They do not support multitasking, but support multithreading. One example of such OS is a specialized real-time operating system MilandrOS. MilandrOS was designed to control the operation of integrated modules. Language PPDL is designed for rapid prototyping and verification of new architectures, as well as creation of system software. Its basic principle: single description several components. From a unified description of core microprocessor or coprocessor its Verilog-description and a number of software components can be generated: QEMU based simulator, assembler/disassembler, the interface to connect to the debugger, and a set of tests. The most important stage in the development of the microprocessor is verification process. Automatic test generators are used to solve this problem. Automatically generated tests allow debugging of functional simulator and then debugging of RTL-architecture description. Integration of verification system and PPDL results in significant reduction of routine verification work. One approach to launch of a new microprocessor on the market is a binary compatibility with existing solutions by using dynamic translation. Besides compatibility dynamic translation solves the issues of improving performance by optimizing JIT-compiler. Elbrus microprocessor is an example of x86 compatible system.