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8086/8088 datasheet documents only base 10 version of the AAD instruction (opcode 0xD5 0x0A), but any other base will work. Later Intel's documentation has the generic form too. NEC V20 and V30 (and possibly other NEC V-series CPUs) always use base 10, and ignore the argument, causing a number of incompatibilities: 0xD5: AAM
Opcode abbreviated from operation code is the portion of a machine language instruction that specifies the operation to be performed. Base instructions form a Turing-complete instruction set. Object model instructions provide an implementation for the Common Type System.
The FPO2 escape opcodes are used by the NEC 72291 floating-point coprocessor - this coprocessor also uses the standard D8-DF escape opcodes, but uses them to encode an instruction set that is unique to the 72291 and not compatible with x87. A listing of the opcodes/instructions supported by the 72291 is available. [34] BRKEM imm8: 0F FF ib
The Intel 8085 ("eighty-eighty-five") is an 8-bit microprocessor produced by Intel and introduced in March 1976. [2] It is the last 8-bit microprocessor developed by Intel. It is software-binary compatible with the more-famous Intel 8080 with only two minor instructions added to support its added interrupt and serial input/output features.
Ralf Brown's Interrupt List (aka RBIL, x86 Interrupt List, MS-DOS Interrupt List or INTER) is a comprehensive list of interrupts, calls, hooks, interfaces, data structures, CMOS settings, memory and port addresses, as well as processor opcodes for x86 machines from the 1981 IBM PC up to 2000 (including many clones), [1] [2] [nb 1] most of it still applying to IBM PC compatibles today.
An opcode table (also called an opcode matrix) is a visual representation of all opcodes in an instruction set. It is arranged such that each axis of the table represents an upper or lower nibble, which combined form the full byte of the opcode. Additional opcode tables can exist for additional instructions created using an opcode prefix.
The opcode for INT3 is 0xCC, as opposed to the opcode for INT immediate8, which is 0xCD immediate8. Since the dedicated 0xCC opcode has some desired special properties for debugging, which are not shared by the normal two-byte opcode for an INT3, assemblers do not normally generate the generic 0xCD 0x03 opcode from mnemonics.
The general form of a VAX-11 instruction would be: opcode [ operand] [ operand] ... Each component being one byte, the opcode a value in the range 0–255, and each operand consisting of two nibbles, the upper 4 bits specifying an addressing mode, and the lower 4 bits (usually) specifying a register number (R0–R15). [8]