Here is the starfield running from a bootblock loader (No MSDOS)
I threw my back out last week, so I could not move the old 8086 to a better place. I wanted to prepare this machine to boot from floppy disk.
The starfield above boots into VGA mode 13h (320×200 256 colors)
This one also has a Sound Blaster, so I can test music in a boot sector also!
My 8088 (v40) board has VGA also now.
I’m waiting for my ISA-PCMCIA card as replacement for a harddisk/floppy
UPDATE 20230721 Bootdemo
I found some parts of our (Edk and Me) bootloader demo.
It was compiled using masm or tasm.
Encountering a problem converting the code into a raw bin, to put on a floppy I diverted to another setup to try to get things working.
Using old code (below) and a example from YT, I made the following setup.
Visual studio code, with the x64 assembly plugin.
xxd as hexviewer.
fasm as assembler (This makes things easier, because it is a native Linux x86 compiler. So no need for dosbox anymore.)
I’ve created a Makefile to automate things.
clean:
rm -f *obj
rm -f *.bin
exec:
fasm demo.asm
fasm boot.asm
cat boot.bin loadpart.bin > demo.bin
qemu-system-x86_64 -boot a -fda demo.bin
Some of our old demo code:
;-------- snip
Start:
JMP SHORT BootHere
NOP
DB "FASH-EDK"
DW 512
DB 2
DW 1
DB 2
DW 0070h
DW 02d0h ;max. aantal sectoren van volume A
DB 0Fdh ;media descriptor
DW 0002h ;aantal sectoren per FAT
DW 0009h ;aantal sectoren per spoor
DW 2
DW 0
BootHere:
mov bp,5
tryboot:
push bp
mov bx,4000h
mov es,bx
mov bx,0
mov cx,2 ;vanaf sector 2
mov dx,0 ;drive A, kant 0
mov ah,02h
MOV AL,8
int 13h ;sector(en) lezen
pop bp
jnc bootok
dec bp
jnz tryboot
bootok:
mov bp,5
;---------- snap
New setup using fasm (bootloader) boot.asm
org 0x7c00 ; still not sure about this, have not found this in our demo
mov bx, 0x1000 ; load sector address
mov es, bx
mov bx, 0x0
; Sector read function
mov dh, 0x0 ; head 0
mov dl, 0x0 ; drive 0
mov ch, 0x0 ; cylinder 0
mov cl, 0x02 ; start sector
readdisk:
mov ah, 0x02 ; read sec
mov al, 0x02 ; demo is > 512 so 2 sectors
int 0x13 ; call bios
mov ax, 0x1000
mov ds, ax
mov es, ax
jmpcode:
jmp 0x1000:0x0 ; far jmp demo
; Expand bin to 512 byte sector
times 510-($-$$) db 0
dw 0xaa55 ; Sector header (ROM as this at the start)
Graphics demo i wrote a long time ago, converted into fasm loadpart.asm
mov ah,0
mov ax, 4f02h ; Set VESA video mode
mov bx, 10dh ; Your video mode number
int 10h
mov al,0
drawall:
mov dx,0
mov cx,0
drawloop:
mov ah,0ch
mov bh,0
push ax
int 10h
pop ax
inc al
inc cx
cmp cx,319
jc drawloop
mov cx,0
inc dx
cmp dx,199
jmp drawloop
jmp drawall
; complete sector with zeros
times 512-($-$$) db 0
Booting the demo in milli seconds using qemu.
Next to do: Write this to floppy and test on real hardware.
A reset starts the virtual machine and boots from a virtual floppy.
The drawing of the pixels is slow, because I used a int 10h function for every pixel, instead of writing to screen memory directly.
ndisasm – disassemble binary
ndisasm loadpart.bin 00000000 B400 mov ah,0x0 00000002 B8024F mov ax,0x4f02 00000005 BB0D01 mov bx,0x10d 00000008 CD10 int 0x10 0000000A B000 mov al,0x0 0000000C BA0000 mov dx,0x0 0000000F B90000 mov cx,0x0 00000012 B40C mov ah,0xc 00000014 B700 mov bh,0x0 00000016 50 push ax 00000017 CD10 int 0x10 00000019 58 pop ax 0000001A FEC0 inc al 0000001C 41 inc cx 0000001D 81F93F01 cmp cx,0x13f 00000021 72EF jc 0x12 00000023 B90000 mov cx,0x0 00000026 42 inc dx 00000027 81FAC700 cmp dx,0xc7 0000002B EBE5 jmp short 0x12 0000002D EBDD jmp short 0xc 0000002F 0000 add [bx+si],al 00000031 0000 add [bx+si],al 00000033 0000 add [bx+si],al 00000035 0000 add [bx+si],al
UPDATE 20230721 Bootdemo update
Got a part working again in PCem.
This is from our bootdemo.
A scroller and sector loader in a bootsector.
Needed some include files
masm, link, exe2com creates a 12- sector sized floppy.
And we’ve got a (little distorted but working) Scroller in boot sector with custom font!
font: db 64 dup (0) ;space
db 0,0,2,2,0,0,0,0 ;!
db 0,2,2,2,2,0,0,0
db 0,2,2,2,2,0,0,0
db 0,2,2,2,2,0,0,0
db 0,0,2,2,0,0,0,0
db 0,0,2,2,0,0,0,0
db 0,0,0,0,0,0,0,0
db 0,0,2,2,0,0,0,0
Followup on
Today two boot projects.
One using a bios extension, so it chip based.
Second is a floppy disk boot program. (Creating a test situation to get our old Boot floppy demo working. ( That one without using an operatingsystem like ms-dos.
Creating a Secondary Bios ROM
NAME mycode
.model small
ORG 0h
.code
dw 0AA55h ; Magic header your bios is looking for
db 16 ; lenght of this rom in 512 bytes == 8k
jmp short clear ; jmp to program
ORG 20h ; start of program
clear: mov cx,10 ; clear, set keyboard led and print 10 # chars
mov ah,0ah
mov al,31h
int 10h
mov bh,0
mov cx,1
start: mov al, 11000000b
out 80h, al
print: mov cx,10
mov ah,0ah
mov al,"#"
int 10h
loop1: nop ; loop until doomsday
jmp loop1
db -68 ; This makes the checksum 0
; steps to take: edit source, make this byte entry 0
; compile using make.bat in dosbox
; check checksum using my python script
; output was 68 hex 0x44
; edit asm file place -68 to make the checksum 0x00 again
; compile and burn to ROM
ORG 2000h ; create end of rom 0000h-1fffh = 8K
END
make.bat in dosbox
@ECHO OFF MASM /DARCH_TYPE="T" /DCPU_TYPE="V" 1; LINK 1; EXE2COM 1.EXE
Python script here: https://www.henriaanstoot.nl/2023/06/20/bios-hacking/
Write EEprom
minipro -w 1.COM -p AT28C64
Part 2 – Bootsector program !
Allmost the same as above, but booting from a Floppy disk.
Video mode info : https://stanislavs.org/helppc/int_10-0.html
Assembly code
use16 ; 16 bits org 0x7c00 ; start address ( change? ) mov ah,0x0 ; ah 0h - video mode mov al,0x0 ; al 0h - mode 0 - 40x25 chars int 10h ; scree routines mov cx,11h ; 11 chars mov ah,0ah ; ah 0ah - print char mode mov al,'#' ; choose char as # int 10h ; execute times 510 - ($-$$) db 0 ; fill rest 512 bytes sector dw 0xaa55 ; magic bytes
Below board replaces 2364 (8k) with a 28c256 (32k 4 roms) socket.
My design in Kicad
The rom can be selected using the pressing restore while starting the C64. ( This button press to select is not my idea but I liked it, when I find the original idea I’ll post it.
After ordering and testing, I’ll attach the Gerber files.
I’ve got some micro cassettes with programs for P2000 and the Microtrainer (SDK-85).
Lets try to get this into executable code again.
(I sold my Philips P2000 last year before I found these tapes)
I bought a Cassette player (voice memo recorder) from Marktplaats (dutch ebay), and a mini jack cable (2.5mm to 3.5mm)
There are two things i’m going to try.
Converting the recorded audio into executable code using python or Puredata.
And making a print to connect the tape player to the SDK-85.
Connecting the player to a soundcard gave me:
Signed 16bit 44.1 kHz
(there are simular projects like this for C64 tapes and alike)
So there will be FFT tricks involved.
While browsing though this book:
I found this schematic: (page A1-39)
So that’s next to build
My BBC Acorn model B is working again. The original monitor is still dead.
Time to play with some machine code and ROMs.
My machine has a NFS rom installed. (NetFS)
Econet was Acorn Computers’s low-cost local area network system, intended for use by schools and small businesses. It was widely used in those areas, and was supported by a large number of different computer and server systems produced both by Acorn and by other companies.
I found a ROM online called Gremlin. It is a 16K rom file. But at the moment I only got some 28C64 (8k) or 28C256 (32k) eeproms.
32k it is. But de beeb having address line A14 floating high, I need to flash the upper 16k of the 32k ROM.
So I made the 16K rom into a 32K using cat
cp Gremlin\ v1.21\ \(1983\)\(Computer\ Concepts\).rom 16k.rom cat Gremlin\ v1.21\ \(1983\)\(Computer\ Concepts\).rom >> 16k.rom minipro -w 16k.rom -p AT28C256
I got the rom from this page:
https://acorn.huininga.nl/pub/unsorted/roms/Gremlin%20v1.21%20(1983)(Computer%20Concepts).rom
Below booting straight into the monitor program.
Manual:
Ben posted a youtube about Wozmon running on his 6502.
In 1976, Steve Wozniac wrote what’s commonly known simply as Wozmon.
Wozmon is a machine-code monitor program written by Wozniak for the Apple 1. In Only 256 bytes ! Being pure 6502 code easily adaptable.
A monitor program allows you to view/edit and run machine code using simple commands.
I’ve got a different setup as Ben’s computer.
But changing the necessary, and it will run on my 6502.
I’m not using rs232 voltage levels (-7 till -25 and +7 till +25 volts).
I’m using a usb serial uart standard 5v leveling stick …
For address decoder see other post
Compiling the Wosmon gave me an error, DEC is not a valid opcode for a bare 6502 .. but we have a 65c02.
Solution: Add -c02 extra opcodes
error 1 in line 187 of "wozmon.s": illegal operand types > DEC ; Decrement A. # fix .. add -c02 vasm6502_oldstyle -c02 -Fbin -dotdir wozmon.s
Below Apple I Manual with the sourcecode for Wozmon
The board seems to be a X Golden Board, except for the missing logo on the motherboard.
Downloaded pcxtbios and compiled the eproms native in linux. So i don´t have to use dosbox any more.
https://github.com/virtualxt/pcxtbios
cd pcxtbios edit make_linux.sh if needed ./make_linux.sh and you should end up with eproms/27512/basicfc.rom eproms/27512/basicf8.rom eproms/27512/basicf6.rom eproms/27512/pcxtbios.rom eproms/27512/basicfa.rom eproms/27128/basicfc.rom eproms/27128/basicf8.rom eproms/27128/basicf6.rom eproms/27128/pcxtbios.rom eproms/27128/basicfa.rom eproms/27256/basicfc.rom eproms/27256/basicf8.rom eproms/27256/basicf6.rom eproms/27256/pcxtbios.rom eproms/27256/basicfa.rom eproms/ibmxt/u18.rom eproms/ibmxt/u19.rom eproms/2764/basicfc.rom eproms/2764/basicf8.rom eproms/2764/basicf6.rom eproms/2764/pcxtbios.rom eproms/2764/basicfa.rom
I didn’t have enough 28C64, but the 28C256 has the same pinout. It just lacks A14 and A13
So I flashed the compiled ROMs for basic to different Eeproms
minipro -w ./2764/basicfc.rom -p AT28C64 minipro -w ./2764/basicf6.rom -p AT28C64 minipro -w ./27256/basicfa.rom -p AT28C256 minipro -w ./27256/basicf8.rom -p AT28C256
These roms need to be placed in sockets ROM6,5,4,3
| ROM7 (BIOS) | fe00:0-ffff:ffff |
| ROM6 Basic | fc00:0000-fdff:ffff |
| ROM5 Basic | fa00:0000-fbff:ffff |
| ROM4 Basic | f800:0000-f9ff:ffff |
| ROM3 Basic | f600:0000-f7ff:ffff |
Machine Code monitor/editor
I tried to find a machine code monitor for 8088 rom, but did not have any luck there.
I tried mumon88, but that didn´t work.
PCem (short for PC Emulator) is an IBM PC emulator for Windows and Linux that specializes in running old operating systems and software that are designed for IBM PC compatibles. Originally developed as an IBM PC XT emulator, it later added support for other IBM PC compatible computers as well.
The big difference with PCem and Dosbox is the fact that you can configure many systems from 8088 to pentium, soundcards and graphic cards (like hercules, CGA, EGA VGA and alike)
You won’t start in MS-DOS, you can boot from a virtual floppy, just what i needed!
Update : Typing boot disk.img in dosbox works
I’ve installed PCem using:
cd pcem/ sudo apt-get install libsdl2-dev sudo apt-get install libopenal-dev tar xzvf ../PCemV17Linux.tar.gz ./configure make clean make # first start (complains about roms, but creates ~/.pcem/... ./pcem cd ~/.pcem/roms # git clone roms git clone https://github.com/BaRRaKudaRain/PCem-ROMs.git mv PCem-ROMs/* ./ rm -rf PCem-ROMs
Below a simple example, booting a floppy with a custom made bootsector.
I’m still searching for our bootblock demo, which uses VGA graphics and a music loader using Soundblaster.
We made this around the 90’s, and i have never seen a demo then booting a demo without dos.
Scrollers, music, starfields etc.
NOTE: Dos calls can’t be used, that’s not loaded. So NO int 21h software functions!
The disk image I created using my real original 5.25″ floppy, and converted this with my Fluxengine.
One of the other bootblock thingy’s I made, An amiga guru meditation error. (below a old capture)
When a corrupted disk or faulty software was booted using a amiga you often could see an error like this, now you could have it on you PC!
Original screen capture of a Guru Meditation.
You can see, mine is a little different, because of the font spacing and color.
PCem info
Systems / motherboards emulated :
8088
AMI XT clone
Atari PC3
Compaq Portable Plus
DTK Clone XT
(c)Anonymous Generic Turbo XT BIOS
IBM PC
IBM PCjr
IBM XT
Juko XT clone
NCR PC4i
Phoenix XT clone
Schneider Euro PC
Tandy 1000
Tandy 1000HX
Thomson TO16 PC
Toshiba T1000
VTech Laser Turbo XT
Zenith Data SupersPort
Xi8088
8086
Amstrad PC1512
Amstrad PC1640
Amstrad PC2086
Amstrad PC3086
Amstrad PC5086
Amstrad PPC512/640
Compaq Deskpro
Olivetti M24
Sinclair PC200/Amstrad PC20
Tandy 1000SL/2
Toshiba T1200
VTech Laser XT3
286
AMI 286 clone
Award 286 clone
Bull Micral 45
Commodore PC30-III
Compaq Portable II
Dell System 200
Epson PC AX
Epson PC AX2e
GW-286CT GEAR
IBM AT
IBM PS/1 Model 2011
IBM PS/2 Model 30-286
IBM PS/2 Model 50
IBM XT Model 286
Samsung SPC-4200P
Samsung SPC-4216P
Toshiba T3100e
Tulip AT Compact
386SX
Acermate 386SX/25N
AMI 386SX clone
Amstrad MegaPC
DTK 386SX clone
Epson PC AX3
IBM PS/1 Model 2121
IBM PS/2 Model 55SX
KMX-C-02
Packard Bell Legend 300SX
Samsung SPC-6033P
386DX
AMI 386DX clone
Compaq Deskpro 386
IBM PS/2 Model 70 (type 3)
IBM PS/2 Model 80
MR 386DX clone
Samsung SPC-6000A
486
AMI 486 clone
AMI WinBIOS 486 clone
Award SiS 496/497
Elonex PC-425X
IBM PS/2 Model 70 (type 4)
Packard Bell PB410A
Socket 4/5/7 (Pentium)
ASUS P/I-P55TVP4
ASUS P/I-P55T2P4
Award 430VX PCI
Epox P55-VA
Intel Advanced/EV (Endeavor)
Intel Advanced/ZP (Zappa)
Intel Premiere/PCI (Batman's Revenge)
Packard Bell PB520R (Robin LC)
Packard Bell PB570 (Hillary)
Super Socket 7 (K6-2/III)
FIC VA-503+
Socket 8 (Pentium Pro)
Intel VS440FX
Slot 1 (Pentium II)
Gigabyte GA-686BX
Graphics cards emulated :
3DFX Voodoo Graphics
3DFX Voodoo 2
ATI Graphics Pro Turbo (Mach64 GX)
ATI Video Xpression (Mach64 VT2)
ATI VGA Edge-16 (ATI-18800)
ATI VGA Charger (ATI-28800)
CGA
Cirrus Logic CL-GD5429
Cirrus Logic CL-GD5430
Cirrus Logic CL-GD5434
Compaq CGA
Diamond Stealth 32 (Tseng ET4000/w32p)
Diamond Stealth 3D 2000 (S3 ViRGE/325)
Hercules
Hercules InColor
IBM EGA
IBM VGA
MDA
MDSI Genius
Number Nine 9FX (S3 Trio64)
OAK OTI-037
OAK OTI-067
Olivetti GO481 (Paradise PVGA1A)
Paradise Bahamas 64 (S3 Vision864)
Phoenix S3 Trio32
Phoenix S3 Trio64
Plantronics ColorPlus
S3 ViRGE/DX
Sigma Color 400
Trident TVGA8900D
Trident TGUI9400CXi
Trident TGUI9440
Trigem Korean VGA (Tseng ET4000AX)
Tseng ET4000AX
Wsye 700
Sound cards emulated :
AdLib
AdLib Gold
Ensoniq AudioPCI
GameBlaster
Gravis UltraSound
Sound Blaster v1.0
Sound Blaster v1.5
Sound Blaster MCV
Sound Blaster v2.0
Sound Blaster Pro v1
Sound Blaster Pro v2
Sound Blaster Pro MCV
Sound Blaster 16
Sound Blaster AWE32
Sound Blaster PCI128
Windows Sound System
When selling a large part of my computer collection I kept a few odd pieces.
Amongst those was a 8088 DIY machine.
It is a 50PTX3 motherboard with a 8088 compatible CPU
Tested the power adapter first, a nice 5V and 12V.
Then I plugged the power in the Motherboard add plugged a test ISA card in the slot.
After turning the machine on I saw the Address leds flashing
A NEC D70108C from 1984, which is 8088 pin compatible with Intel 8088 but faster, and has some extra functionality.
The empty socket is for the 8087 Co-processor.
Everything pretty dirty
Adding an 8bit Isa hercules/CGA card.
It starts! .. But there is no Floppy controller (yet)
I’ve dumped the Bios to a file and used a hexeditor to play around.
So that’s why there is a bad checksum.
Installing a ZIF socket (Zero Insertion Force) to make things easier to modify.
Burned GlaBios on the Eprom and now I can continue to play around.
So why? Why this all ..
I want to play around with old 8088 assembly code again, but not as I did before using a Dos machine, but hardcoded into Eproms.
I’ve got 8 banks for ROMs and the source code for GlaBios is available.
In the past Edk and me wrote a boot demo, so it was not utilizing Ms-Dos functions. Maybe i can get some graphical and sound stuff working straight from the Bios.
Some commands:
# Dump the bios to file minipro -w original.rom -p AT2764A@DIP28 xxd and hexdump to view the dump I've used ghex to alter the ROM # Write a new bios to a 28C64 (same Eeprom i've used for the C64 Cartridges) minipro -w /home/henri/Downloads/MYROM -p AT28C64
GlaBios source code:
https://github.com/640-KB/GLaBIOS/blob/main/src/GLABIOS.ASM
I was planning to disassemble the Phoenix Bios, but it’s quite hard to differentiate between code and data, there are no named pointers and you have to interpret every line of code.
So GlaBios it is ..
First code to look at:
This is after the whole post reset. There is a reset pointer at ffff:fffe Which points to the bootstrap routine, which ends in below machine code. I'm going to plug my own code over here. (See the funny remark about Monster as being displayed in one of above pictures) ;----------------------------------------------------------------------------; ; INT 18 - Unbootable IPL ;----------------------------------------------------------------------------; ; Display a disk boot failure message and wait for a key to cold reboot. ; ; This may be re-vectored to ROM BASIC, if present. ; ; Size: 18 bytes ;----------------------------------------------------------------------------; INT_18 PROC ASSUME DS:_BDA_ABS PRINT_SZ BOOT_FAIL ; print boot failure string XOR AX, AX ; AH = 0 (wait for key) MOV DS, AX ; DS = 0000 MOV WARM_FLAG_ABS, AX ; do a cold boot INT 16H ; wait for key press JMP BOOT ; reboot INT_18 ENDP BOOT ENDP ;----------------------------------------------------------------------------; ; ; END OF BIOS POST/BOOTSTRAP ; ;----------------------------------------------------------------------------; ASSUME DS:_BDA STRINGS PROC ;----------------------------------------------------------------------------; ; Banner Strings ; BANNER_STRINGS PROC IF POST_GLADOS EQ 1 BOOT_BEGIN DB CR, LF DB 'Starting GLaDOS...' NL2_Z DB LF ; two NL's, null term'd ENDIF NL_Z DB CR, LF, 0 ; one NL, null term'd BOOT_FAIL DB 'Disk Boot Fail.' DB ' You monster.' NL2_ANY_KEY DB LF NL_ANY_KEY DB CR, LF ANY_KEY DB 'Press the Any Key' DB '...'
Assembly stuff
I’ve got Dosbox installed on my machine.
git clone https://github.com/640-KB/GLaBIOS.git
I copied MASM.EXE and LINK.EXE in the GLaBios src directory.
edit make.bat
change
MASM GLABIOS;
into
MASM /DVER_DATE=”05/24/23″ /DARCH_TYPE=”T” /DCPU_TYPE=”V” GLABIOS;
start dosbox
mount c: /home/henri/projects/
c:
cd glabios/src
make.bat
