The Intel 8086 Instruction SetModes, Protected
While this approach gave the 8086 a flexible instruction set, it created a problem in the long run for the x86 architecture, requiring complicated logic to determine instruction length. One benefit of RISC-based processors such as the Apple M1 is that they have (mostly) constant instruction leng...
The 8086's instruction set was designed with a new concept, the "ModR/M" byte, which usually follows the opcode byte. The ModR/M byte specifies the memory addressing mode and the register (or registers) to use, allowing that information to be moved out of the opcode. For instance, where...
The CMC (complement carry flag) instruction from the original 8086 instruction set is also used by Windows but not Linux. The same holds for BSR (bit scan reverse) from the 80386. They are not exactly common (measured at less than 0.01%), but still interesting to see that ...
then DI will automatically be incremented by one for a byte string or incremented by two for a word String Instruction in 8086. If the directionflagis set, DI will be automatically decremented by ono for a byte string or decremented by two for a word string. STOS does not affect any flag...
This chapter discusses the details of the significant changes in the 80×86 instruction set and architecture as the 8086 evolved into the 80386. All the new chips were introduced at higher clock speeds and with new instructions. The 186 added a number of new instructions and new forms of inst...
The Instruction Set Architecture, or ISA, is defined as that part of the processor architecture related to programming, including the native data types, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external IO. With the exception of some small ...
1. A method for decoding instructions in parallel in a computer system, wherein the computer system includes an instruction cache, a boundary pattern storage, an encrypter, a decrypter, a prefetcher and two or more decoders, said method comprising the steps of: (a) fetching a set of inst...
The x86 instruction set has evolved over time. Originally, it was based around 16 bits in the 8086, later 32bit support was added. Recently AMD extended the general purpose registers to 64 bits, and Intel have added 128 bit vector (SIMD) registers, and will upgrade them to 256 bits when...
Fundamentals of Digital Logic and Microcomputer Design; Rafiquzzaman (5th edition, 2006, John Wiley & Sons)Rafiquzzaman '05] Mohamed Rafiquzzaman: Fundamentals of Digital Logic and Microcomputer Design, Fifth Edition, Wiley - Interscience, 2005....