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Adding BCD numbers using these opcodes is a complex task, and requires many instructions to add even modest numbers. It can also require a large amount of memory. [2] If only doing integer calculations, then all integer calculations are exact, so the radix of the number representation is not important for accuracy.
Opcode Instruction Description Type of instruction 0x58 add: Add two values, returning a new value. Base instruction 0xD6 add.ovf: Add signed integer values with overflow check. Base instruction 0xD7 add.ovf.un: Add unsigned integer values with overflow check. Base instruction 0x5F and: Bitwise AND of two integral values, returns an integral value.
Opcode AAA: ASCII adjust AL after addition: used with unpacked binary-coded decimal: 0x37: AAD: ASCII adjust AX before division: 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.
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.
Minimal instruction set computer (MISC) is a central processing unit (CPU) architecture, usually in the form of a microprocessor, with a very small number of basic operations and corresponding opcodes, together forming an instruction set. Such sets are commonly stack-based rather than register-based to reduce the size of operand specifiers.
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
Opcode for OR 0,0,0. [7] LDI 26,0: 4 0x34000034 Palindromic NOP - that is, an instruction that executes as NOP regardless of whether byte order is interpreted as little-endian or big-endian. Some PA-RISC system instructions are required to be followed by seven palindromic NOPs. [7] POWER, PowerPC, Power ISA: NOP: 4 0x60000000 Opcode for ori r0 ...
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.