This project is an abstract logic model of the Intel 8080 microprocessor written in C. To be more precise, this model replicates a clone of the original Intel 8080 called KR580VM80A manufactured in Russia.
According to tests, this models works exactly the same way as the real KR580VM80A including vaguely documented or even undocumented features. The extensive "8080/8085 CPU Exerciser" test by Ian Bartholomew provides strong guarantees of the match.
This purpose of this fork of the original project is to allow creating more than one 8080 cpu instance in my emulator. The core logic is 95% the same, but I had to modify the interface significantly.
There is now also a function to call to trigger an interrupt. This is provisional as I anticipate the current mechanism will be somewhat awkward. Specifically, it is the responsibility of the caller to re-raise an interrupt if the interrupt condition is still true after the current ISR completes. It isn't obvious that the caller can know when that happens! I suspect I'll have to add a callback function for this.
Use any standard C compiler, for example, GNU C, Visual Studio or TCC. But the Makefile requires GNU Make.
Type make, and it should build and run the test suite. It must print out
the following:
*********************************
File "CPUTEST.COM" loaded, size 19200
DIAGNOSTICS II V1.2 - CPU TEST
COPYRIGHT (C) 1981 - SUPERSOFT ASSOCIATES
ABCDEFGHIJKLMNOPQRSTUVWXYZ
CPU IS 8080/8085
BEGIN TIMING TEST
END TIMING TEST
CPU TESTS OK
Jump to 0000 from 3B25
*********************************
File "TEST.COM" loaded, size 1793
MICROCOSM ASSOCIATES 8080/8085 CPU DIAGNOSTIC VERSION 1.0 (C) 1980
CPU IS OPERATIONAL
Jump to 0000 from 014F
*********************************
File "8080PRE.COM" loaded, size 1024
8080 Preliminary tests complete
Jump to 0000 from 032F
*********************************
File "8080EX1.COM" loaded, size 4608
8080 instruction exerciser (KR580VM80A CPU)
dad <b,d,h,sp>................ OK
aluop nn...................... OK
aluop <b,c,d,e,h,l,m,a>....... OK
<daa,cma,stc,cmc>............. OK
<inr,dcr> a................... OK
<inr,dcr> b................... OK
<inx,dcx> b................... OK
<inr,dcr> c................... OK
<inr,dcr> d................... OK
<inx,dcx> d................... OK
<inr,dcr> e................... OK
<inr,dcr> h................... OK
<inx,dcx> h................... OK
<inr,dcr> l................... OK
<inr,dcr> m................... OK
<inx,dcx> sp.................. OK
lhld nnnn..................... OK
shld nnnn..................... OK
lxi <b,d,h,sp>,nnnn........... OK
ldax <b,d>.................... OK
mvi <b,c,d,e,h,l,m,a>,nn...... OK
mov <bcdehla>,<bcdehla>....... OK
sta nnnn / lda nnnn........... OK
<rlc,rrc,ral,rar>............. OK
stax <b,d>.................... OK
Tests complete
Jump to 0000 from 0137
The test suite includes four tests at the moment:
-
8080/8085 CPU Diagnostic, version 1.0, by Microcosm Associates (file
TEST.COM) -
Diagnostics II, version 1.2, CPU test by Supersoft Associates (file
CPUTEST.COM) -
8080/8085 CPU Exerciser by Ian Bartholomew and Frank Cringles
- The preliminary test (file
8080PRE.COM). - The basic excerciser (file
8080EX1.COM). This file is a copy of the vanilla8080EXER.COMfile having CRCs from the real KR580VM80A contributed by Alexander Timoshenko and Viacheslav Slavinsky.
- The preliminary test (file
All tests pass.
Although the most popular CPUs today use little-endian convention, if your host computer is big-endian, comment out "#define LITTLE_ENDIAN" in i8080.h.
The implemention of the Intel 8080 model is self-contained and independent. The caller creates a cpu instance by calling i8080_new and passing in callback functions to handle memory read, memory write, input byte, and output byte behavior.
The example of use is the test suite (i8080_test.c).
It creates bare miminum hardware plumbing to run tests.
- Viacheslav Slavinsky, Vector-06C FPGA Replica
- Dmitry Tselikov, Bashrikia-2M and Radio-86RK on Altera DE1
- Ian Bartholomew, 8080/8085 CPU Exerciser
- Frank Cringle, The original exerciser for the Z80
- zx.pk.ru and nedopc.org/forum communities