Questions tagged [8080]
For questions about the Intel 8080 8-bit microprocessor
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How much does Micro-80 BASIC resemble Microsoft BASIC?
The first DIY Soviet home computer Micro-80 and its successor Radio-86RK had an implementation of BASIC available (albeit not in ROM, but as an loadable binary). A page from which the link is taken ...
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What is the output of the Supersoft Diagnostics II v1.2 on an Intel 8080?
Supersoft Diagnostics II is a program to test 8080 and Z80 CPUs, as mentioned in this answer, and questions here and here. As well as sources mentioned in those posts, the program binary and a ...
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Does the Intel 8080 ANI instruction clear or update the half-carry?
It's known and documented that on the Intel 8080 most logical operations (including all OR and XOR operations) clear the half-carry (auxiliary carry) flag. A known exception is the ANA instruction, ...
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What do the pins D0-D7 on the Intel 8080 exactly signify?
I am currently trying to create a FPGA styled simulator of the 8080 in C. I have a couple of questions regarding the D0-D7 pins. As far as I can see the D0-D7 lines are used in order to store data (a ...
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Was the Game Boy CPU a completely new layout?
As explained on the Wikipedia Game Boy article and Is the Game Boy Sharp LR35902 object-compatible with the 8080/Z-80?, the Game Boy used a custom CPU that was fairly close to being a superset of the ...
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Long Term Prevalence of 8080 Code Over Z80 Code in Software Packages
TL;DR:
The Z80 was introduced not long after the 8080 and replaced it quickly and almost entirely for personal computing. Still, a large chunk of new software written stayed with 8080 code, making no ...
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Is there any known magic number signature for CP/M-80 program files?
I'm looking for a way to identify CP/M-80 (i.e. 8080 code) program files (.COM) from their content. A process usually known as Magic Number or File Signature detection, intended to identify a file by ...
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Anyone up for decompiling some 8080 code for Kaleidoscope?
I came across a series of blog posts about Kaleidoscope, a demo program for the Cromemco Dazzler graphics card. The series implements an emulator for the system so that it could run this code again, ...
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Running CP/M on my own Intel 8080 emulator
I recently finished writing an emulator for the Intel 8080, having passed all of the usual test suites, and wanted to try running an actual OS on it (such as CP/M). I'm aware that I would have to ...
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Why are the Intel 8080's rotate instructions called opposite to intuition?
The Intel 8080 has two pairs of instructions for rotating the value of the accumulator -- RLC/RRC and RAL/RAR.
One of them shifts the 8 bits in the accumulator circularly, writing out into the carry ...
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Why did the 8080's PUSH PSW write one reserved bit as 1 and the other two as 0?
The x86 "flags" register, which holds condition codes and other processor status bits, has several reserved bits with fixed values, but these fixed values are not all the same. In ...
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Game assembled using RGBDS can't access cartridge RAM
Any writes I do to cartridge RAM on my test game assembled with RGBDS are silently ignored. I wanted to move the stack pointer to cartridge RAM to have more room in high ram to use as a scratchpad, ...
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Why did the Z80 break 8080 compatibility?
Although the Z80 is nearly fully backward compatible with the Intel 8080, there are minor differences such as the Z80 handling the parity flag differently with certain operations.
Why? Would providing ...
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Can the window only be moved once per frame on the Game Boy?
I wanted to cover the top part of the screen to use as a status bar for a game. My idea was to use the Game Boy's window feature to do so. But I ran into a problem: The window's size is fixed to be ...
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Getting a loading seam to work with 2x2 metatiles
I'm working on a prototype for a scrolling loading seam similar to Pokemon where the screen scrolls incrementally by 8 pixels with each direction button press, and new tile graphics are drawn off the ...
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