adriancable / 8086tiny Goto Github PK

Not sure but curious since these chips were apparently quite similar: does this also support the 8088?

I just uploaded some spiffing snaps of a modern machine yesterday (feel free to use)...

• front
• rear
• inside view one
• inside view two

... the machine in question was donated to the Australian Computer Museum Society.

Look at this block in the bios:

mov	ah, 0
cpu	186
shl	ax, 9
extended_read_disk
shr	ax, 9
cpu	8086
mov	ah, 0x02	; Put read code back

cmp	al, 0
je	rd_error

The extended_read_disk instruction writes the error to AL. But right after the read we shift AX back 9 bits to right (shr ax, 9) which overrides AL. So what's even the point of cmp al, 0 and setting AL in extended_read_disk?

And even when you fix the bios, the read function in 8086tiny.c is still wrong. You use AX as length to read. But read() returns, for example 512, which is 0 inside AL because of the overflow. So even if we don't shift bits after the read AL indicates "error".

Are there any workarounds for not having timeb.h? https://www.gnu.org/software/gnulib/manual/html_node/sys_002ftimeb_002eh.html

The CAST macro is used to generate unaligned accesses. This breaks compatibility on architectures which don't support unaligned access, like ARM.

I'm looking into this issue and it seems that I would have to rewrite the CAST macro to be an inline function that uses byte loads.

Post macro-expansion, the code in

(scratch_int = *(unsigned short *)&mem[rm_addr]) &&
        !(scratch2_uint = (unsigned)(scratch_uint = (regs16[i_w + 1] << 16) + regs16[0]) / scratch_int,
          scratch2_uint - (unsigned short)scratch2_uint)
    ? regs16[i_w + 1] = scratch_uint - scratch_int * (*regs16 = scratch2_uint)

The type of scratch_int * (*regs16 = scratch2_uint) is int due to the LHS being an int and the RHS being an unsigned short. It is promoted to unsigned int before the subtraction. A counterexample generated by CBMC was -
scratch_int = 33793, scratch_uint = 2181038080, scratch2_uint (division result) = 64541. scratch_int * scratch2_uint = 2181034013 does not fit inside a 4-byte int.

Detected using Frama-C (eva) and CBMC while doing a project for the Software Verification and Analysis course under Prof @mksrivas at CMI

have a freelancer working on this port currently.

emcc 8086tiny.c -DNO_GRAPHICS -o 8086tiny.html -fsigned-char -O1 --embed-file bios --embed-file fd.img

node 8086tiny.js bios fd.img

keyboard , sound and graphics not working.

What version the 8086tiny need? i have SDL2

When i run 'make' the output is this:

cc 8086tiny.c sdl-config --cflags --libs -O3 -fsigned-char -std=c99 -o 8086tiny
/bin/sh: 1: sdl-config: not found
8086tiny.c:18:10: fatal error: SDL.h: No such file or directory
_ 18 | #include "SDL.h"
___ | ^~~~~~~
compilation terminated.
make: *** [Makefile:16: 8086tiny] Error 1

Hello, I'm trying to boot linux ELKS via 8086tiny but the boot stops like this:
ELKS.......................................................................................................................................................... ELKS Setup ....L0831C3AH00S0A t02D0 f0FC6 d12BA Direct console, scan kbd 80x25 emulating ANSI (3 virtual consoles)
At this point it just hangs.
Is there a way to get the boot log or something to figure out what has gone wrong?
Thanks in advance!

I think your LEA implementation is wrong.

When I want to execute, for example, lea sp, ... the c variable op_from_addr is 0xf0008 which points inside mem to ES instead to SP. This is because you calculate

op_from_addr = REGS_BASE + i_reg * 2;

for your LEA implementation instead of just

op_from_addr = REGS_BASE + i_reg;

(without * 2).

Q1: In bios.asm, how can I save a value (number, string, etc.) such as the content of biosstr (string) in a memory area of the emulator, and then read and print that memory area from 8086tiny.c?

Q2: Same question as Q1 but in reverse, storing a variable in 8086tiny.c, and then reading and printing that value from bios.asm.

Q3: In FreeDOS kernel, how can I save a value (number, string, etc.) in a memory area of the emulator, and then read and print that memory area from 8086tiny.c or from bios.asm?

Q4: Same question as Q3 but in reverse, storing a variable in 8086tiny.c or bios.asm, and then reading and printing that value from FreeDOS kernel.

Q5: I have same question: https://8086tiny.freeforums.net/thread/82/starting-exe-files-command-line

Q6: I have same question: https://8086tiny.freeforums.net/thread/62/local-drive-access

regards,
Danny.

Is there a way to interface the com(x) ports under DOS to access USB devices (modem in particular)