This reprint of an Intel title is also available from Intel. It is divided into five major sections: application programming, which is the non-system programming view of the machine; system programming, which is the larger view of the microprocessor seen by the operating system programmer with the attendant resource management concerns; numeric processing, since the microprocessor has a numeric coprocessor built in; compatibility with pre-existing Intel microprocessors in the 80X86 family; and the instruction set of the microprocessor. It also contains a set of appendices, a glossary, and an index.

The application portion describes the basic model of the microprocessor--its memory organization, register set, flags, and operand addressing. The system programming section assumes a basic knowledge of operating system concepts and describes Intel’s implementation of these concepts. The additional items visible to the system programmer rather than the application programmer are described here. Included, at the hardware and supporting data structure level, are memory management and protection, multitasking support, exception and interrupts, and multiprocessing. This section is approximately one quarter of the book. The numeric processing portion describes the details of the built-in numeric coprocessor. This section covers its architecture and instruction set and system-level considerations.

The instruction set portion takes up approximately half the book. The instructions are arranged in opcode mnemonic order. Each instruction description includes the opcode, instruction mnemonic, execution clocks, and an operation portion that describes the instruction’s execution in algorithmic form, the status flags affected, and possible exceptions (such as protected mode and real mode). Descriptions range from one page for an instruction like AAA (ASCII Adjust after Addition) to six pages for a CALL instruction with its protection considerations. Most instructions are described in a page or two. Appendices include opcode maps, instruction format and timing, and flag cross references.

The book supplies everything Intel thinks a programmer should know about the i486 microprocessor. The information is densely packed and may require more than one reading to obtain a clear picture.