2018年5月16日 · Looking through the table of instructions supported by the 8080, few others stand out as not being easy one-to-one translations, although as Peter Cordes points out many 1-byte instructions become 2-byte instructions on the 8086 (e.g. MOV C,M or Z80 equivalent ld c,(hl) which is 4Eh on the 8080 would convert to MOV CL,[BX] or 8Ah 0Fh on the ...

2022年4月21日 · For the 8086, unaligned word loads (first byte at an odd address) require two memory accesses, but an aligned word (first byte at an even address) can be loaded in one. This is excellently explained by answers over at Electronics Stack Exchange: ‘Accessing odd address memory locations in 8086’.

The 1979 version of the 8086 family user's manual is available at different places in the internet, see 1,2,3. It seems there is no newer version available. This manual documents the single-stepping feature in figure 2-29 on page 2-23 and figure …

2018年10月4日 · Its 8086 emulation is implemented in src/808x.c — you can see there that it keeps track of the cycles taken by each instruction, and each memory access, and takes into account memory prefetches and the cycles lost to memory refresh. It even emulates CGA snow!

2020年2月16日 · The 8086 must wait for Busy before executing any other 8089 command. When done, the 8089 will reset the Busy-Flag 0h, signalling that the channel is finished. The same happens as well when a channel program stops at a defined point (usually by a HALT instruction). The Busy-Flag can be polled by the 8086 as the CB is always in shared memory.

2021年3月9日 · Intel has named the i7-8086K in honor of the 8086 processor, though itself it is a 64-bit processor. And we still see in embedded systems or MIL-SPEC platforms there are old CPUs like the 80386 produced in the original, say, 1 µm process.

2018年6月3日 · The emulator implements a subset of the 8086 instruction set described here. I plan to implement bios routines for character I/O in int 10 and int 16 . But then I realized that the bios code is still just machine code, so I'll still need some extra step to peek outside of the VM and call "host" functions like putchar() and getchar() .

A special feature of the 8042 is a built-in bus interface to allow it to easily integrate with Intel master CPUs like the 8086 - but it doesn't necessarily nead to run along one of them. The 8255 however, is a completely different thing - It's a peripheral chip to the 80xx line of CPUs that provides 3 byte-wide digital I/O ports.

2019年7月26日 · The 8086 has no programmer-visible supervisor/user model in the instruction set architecture. However, it exposes a lot of state information through its pins, such as pins S0, S1 and S2 that interface to a bus controller (like the Intel 8288). The S0, S1 and S2 pins indicate what kind of access the 8086 is making: code, data, I/O and so on.

2017年5月17日 · When the 8086 was designed, RAM was so valuable you couldn't simply assume some arbitrary value. On the other hand, you could most probably assume valid RAM in the vector area, thus lower memory area - because this definitely needs to be populated for interrupt vectors - Maybe this was the reason for SS=0.