Search results
Results from the WOW.Com Content Network
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
On the 8086, 8088, and 80186, the result of an effective address that overflows 20 bits is that the address "wraps around" to the zero end of the address range, i.e. it is taken modulo 2^20 (2^20 = 1048576 = 0x100000). However, the 80286 has 24 address bits and computes effective addresses to 24 bits even in real mode.
This derived directly from the hardware design of the Intel 8086 (and, subsequently, the closely related 8088), which had exactly 20 address pins. (Both were packaged in 40-pin DIP packages; even with only 20 address lines, the address and data buses were multiplexed to fit all the address and data lines within the limited pin count.)
The Intel 8086 and subsequent processors in the x86 series have an HLT (halt) instruction, opcode F4, which stops instruction execution and places the processor in a HALT state. An enabled interrupt, a debug exception, the BINIT signal, the INIT signal, or the RESET signal resumes execution, which means the processor can always be restarted. [ 15 ]
Front panel of an IBM 701 computer introduced in 1952. Lights in the middle display the contents of various registers. The instruction counter is at the lower left.. The program counter (PC), [1] commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), [2] [1] the instruction counter, [3] or just part of ...
EMS was a specification available on all PCs, including those based on the Intel 8086 and Intel 8088, which allowed add-on hardware to page small chunks of memory in and out (bank switching) of the "real mode" addressing space (0x0400–0xFFFF). This allowed 16-bit real-mode DOS programs to access several megabytes of RAM through a hole in real ...
All x86 processors from the 8086 onward had the HLT instruction, but it was not used by MS-DOS prior to 6.0 [2] and was not specifically designed to reduce power consumption until the release of the Intel DX4 processor in 1994. MS-DOS 6.0 provided a POWER.EXE that could be installed in CONFIG.SYS and in Microsoft's tests it saved 5%. [3]
The 16-bit Intel 8088 and Intel 8086 supported 20-bit addressing via segmentation, allowing them to access 1 MiB rather than 64 KiB of memory. All Intel Pentium processors since the Pentium Pro include Physical Address Extensions (PAE) which support mapping 36-bit physical addresses to 32-bit virtual addresses.