https://github.com/turkishrational/fasm

Flat Assembler (FASM) for TRDOS 386 Operating System
https://github.com/turkishrational/fasm

32bit 386 386dos 80386 adaptation assembler assembly binary compiler dos fasm file flat nasm port prg trdos trdos386 x86

Last synced: about 2 months ago
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Flat Assembler (FASM) for TRDOS 386 Operating System

• Host: GitHub
• URL: https://github.com/turkishrational/fasm
• Owner: turkishrational
• Created: 2024-10-06T17:12:18.000Z (4 months ago)
• Default Branch: main
• Last Pushed: 2024-12-19T18:13:28.000Z (about 2 months ago)
• Last Synced: 2024-12-19T18:35:42.313Z (about 2 months ago)
• Topics: 32bit, 386, 386dos, 80386, adaptation, assembler, assembly, binary, compiler, dos, fasm, file, flat, nasm, port, prg, trdos, trdos386, x86
• Language: Assembly
• Homepage:
• Size: 68.7 MB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
## Flat Assembler (FASM) for TRDOS 386 Operating System

TRDOS 386 adaptation/port of Tomasz Grysztar's Flat Assembler (v1.73.32)

.. FASM.PRG assembles itself ..

NOTE:

.PRG files are TRDOS 386 (32 bit, x86) flat binary executables. They start at virtual address 0 always.

(Similar to 16 bit MSDOS .COM files which start at 100h.) 

TRDOS 386 does not use segments. (Demand Paging method is used. The kernel page directory is set for 1 to 1

physical memory layout. Interrupts are set to run in the 1st 4MB -PDE 0- also with user's page directories.

User's segment selectors are set for 4MB base address with 4GB-4MB limit.)

(TRDOS 386 kernel handles memory as virtually -up to 4GB- flat memory by using system and user page tables.)

((In fact, TRDOS 386 programs start at 4MB linear base address but their page directories are set

  to provide virtual address 0 as start address. Maximum usable -virtual- memory for TRDOS 386 programs is 4GB-4MB.) 

How FASM assembles a TRDOS 386 binary: The answer is 'It is very easy!'.

fasm example.asm  -> creates EXAMPLE.BIN file (it will be able to run just after renaming it as EXAMPLE.PRG file) 

fasm example.asm example.prg -> creates EXAMPLE.PRG file.

Operating system depended files: FASM.ASM, SYSTEM.INC (other files are common source code files of FASM.)

Question: By using FASM.PRG in TRDOS 386 environment...

          Is it possible to assemble executable files for WINDOWS, LINUX, DOS or another operating system?

Answer: Yes. Just as FASM.EXE and Linux FASM do it.

Erdogan Tan - October 2024