In this repository, you will find an Intel 8080 emulator, a disassembler and an assembler.
The emulator itself is in i8080.c. You can execute your own binary, execute the cpu tests or execute an interrupt test, more like a demo, I made. I decided to use IO PORT 0 to output characters. So, if you make your own program, by using "out 0" you can output a char to the screen. Example:
[joseguilhermecr@jose-desktop 8080]$ ./i8080 assembler/file.hex
Starting with: start_pc = 0x100 memory_offset = 0x100 debug = 0 step_by_step = 0
Hello There, 8080!
The disassembler was made before the actual emulator, so I could get familiar with the instructions. Be aware that the disassembler can't differentiate instructions from data. So, a really weird sequence of instructions may actually be data that was interpreted as instructions.
The assembler was made in Rust and is mostly functional. Assembler commands include:
.org to specify the origin of the program in memory.
.db to define a byte.
.dw to define a word.
.asciiz to define a null terminated string.
You can assemble code by running:
assembler "file.asm" --output "optional_output_name.hex".
If you don't specify the name of the output file, it will be called file.hex.
CPU tests were made to be run within CP/M, an ancient OS, and, therefore, they made use of a BIOS. I put a return instruction at the address where the BIOS function should be and just checked whether the tests had jumped to that address so I could print the information they wanted to show. That's how the tests are able to print to the screen.
Output when running i8080 cpu_tests:
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Loaded file cpu/tests/TEST.COM with size 1793 and offset 256.
MICROCOSM ASSOCIATES 8080/8085 CPU DIAGNOSTIC VERSION 1.0 (C) 1980
CPU IS OPERATIONAL
Got to 0000, PC before = 14FH 335
Done instructions: 2148. Done cycles: 19281
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Loaded file cpu/tests/8080PRE.COM with size 1024 and offset 256.
8080 Preliminary tests complete
Got to 0000, PC before = 32FH 815
Done instructions: 1059. Done cycles: 7797
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Loaded file cpu/tests/8080EXM.COM with size 4608 and offset 256.
8080 instruction exerciser
dad <b,d,h,sp>................ PASS! crc is:14474ba6
aluop nn...................... PASS! crc is:9e922f9e
aluop <b,c,d,e,h,l,m,a>....... PASS! crc is:cf762c86
<daa,cma,stc,cmc>............. PASS! crc is:bb3f030c
<inr,dcr> a................... PASS! crc is:adb6460e
<inr,dcr> b................... PASS! crc is:83ed1345
<inx,dcx> b................... PASS! crc is:f79287cd
<inr,dcr> c................... PASS! crc is:e5f6721b
<inr,dcr> d................... PASS! crc is:15b5579a
<inx,dcx> d................... PASS! crc is:7f4e2501
<inr,dcr> e................... PASS! crc is:cf2ab396
<inr,dcr> h................... PASS! crc is:12b2952c
<inx,dcx> h................... PASS! crc is:9f2b23c0
<inr,dcr> l................... PASS! crc is:ff57d356
<inr,dcr> m................... PASS! crc is:92e963bd
<inx,dcx> sp.................. PASS! crc is:d5702fab
lhld nnnn..................... PASS! crc is:a9c3d5cb
shld nnnn..................... PASS! crc is:e8864f26
lxi <b,d,h,sp>,nnnn........... PASS! crc is:fcf46e12
ldax <b,d>.................... PASS! crc is:2b821d5f
mvi <b,c,d,e,h,l,m,a>,nn...... PASS! crc is:eaa72044
mov <bcdehla>,<bcdehla>....... PASS! crc is:10b58cee
sta nnnn / lda nnnn........... PASS! crc is:ed57af72
<rlc,rrc,ral,rar>............. PASS! crc is:e0d89235
stax <b,d>.................... PASS! crc is:2b0471e9
Tests complete
Got to 0000, PC before = 137H 311
Done instructions: 2919050420. Done cycles: 23835662278
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Loaded file cpu/tests/CPUTEST.COM with size 19200 and offset 256.
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
Got to 0000, PC before = 3B25H 15141
Done instructions: 33971128. Done cycles: 255663225
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