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22

Ken Shirriff has, as so often, a nice table to start with - especially nice to detect the 'undocumented' ones. All opcodes in lower case are 'undocumented'. With sorting his table according to the 'octal' (2-3-3) decoding logic the 8085 uses (*1), the first are nicely grouped where the 8080 only decoded NOP: (NOP - Not undocumented, but on the 8080 it ...


20

I'm going to say "No" simply because the 8086 doesn't support the alternate registers of the Z80. That was a fairly important concept that you can not directly mimic on the 8086. Mind, if you're willing to dedicate memory and whatnot to support it, then, "sure". Replace the Z80 functionality with a macro, say. But now you're stretching it....


12

I've found three programs which together make up quite a comprehensive test suite. 8080/8085 CPU Diagnostic, version 1.0, by Microcosm Associates Diagnostics II, version 1.2, CPU test by Supersoft Associates 8080/8085 CPU Exerciser by Ian Bartholomew and Frank Cringles The assembly of the Microcosm tests, and compiled COM programs of the other two tests ...


11

The 8085 added two new instruction functions: SIM and RIM. These instructions differ from the 8080 instructions in that each has multiple functions. The SIM instruction sets the interrupt mask and optionally writes one bit of data to the serial interface. The RIM instruction reads one bit from the serial interface (if one is present) and the interrupt ...


9

Sure, a lot can be done. Source code translation always offers the possibility to replace one instruction by a sequence - like Intel already did for a few. This would as well solve the issue of incompatible hardware, like simply exchanging all registers with a copy in memory when the alternate register set is selected. Just, who should do this? Intel had ...


8

The 8080 sets the carry flag when the unsigned value subtracted is greater than the unsigned value it is subtracted from. So for SUB B carry is set if and only if the unsigned value of B register is greater than the unsigned value of A register. What the manual is getting at is that subtraction can be performed by adding the two's complement of the value ...


6

To answer your specific question, the 0x20 and 0x30 opcodes on the 8080 were undefined. In practice they were equivalent to NOP (0x00). A handy table of 8080 instructions can be found here: http://pastraiser.com/cpu/i8080/i8080_opcodes.html


2

I'm not really clear what the underlaying problem/question is, as you already cite all relevant information to answer waht seams to be the question. Thus it's hard to give a straight answer, meaning I have to 'swing along' - so maybe lets start with an Instruction Overview To start with, let's look at the cycle data: 8080 ...


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