Intel 8080 (KR580VM80A) microprocessor core model

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.

Build

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

Tests

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 vanilla 8080EXER.COM file having CRCs from the real KR580VM80A contributed by Alexander Timoshenko and Viacheslav Slavinsky.

All tests pass.

Note

Unfortunately, the current implementation needs the little-endian system to run properly. It uses unions to mix different data types, and such technique is not portable across little- and big-endian systems. Fortunately, most of popular desktop systems running Windows and OSX are based on Intel x86/64 which is little endian. Also, this emulator was tested on the PIC32 platform (little endian as well).

Usage

The implemention of the Intel 8080 model is self-contained and independant. It only requires the i8080_hal.h header providing the hardware abstraction layer.

The example of use is the test suite (i8080_test.c and i8080_hal.c). It creates bare miminum hardware plumbing to run tests.

Credits

• 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

Links

• Серия микросхем КР580