Old-School DevKit

This development kit is focused on retrocomputers, running natively on target machines as well as on modern computers.

Tools included

• OSASMZ80
  Old-School Assembler for Z80 (Beta)
• OSASM80
  Old-School Assembler for i80 (Beta)
• OSASM86
  Old-School Assembler for i86 (In planning)
• OSLINK
  Old-School Multiplatform Linker (Pre-release)
• OSOUTBIN
  Old-School Generic Binary Generator (Beta)
• OSOUTCOM
  Old-School COM Executable Generator (Beta)
• OSOUTEXE
  Old-School EXE Executable Generator (In planning)
• OSOUTPCB
  Old-School PC Boot Sector Generator (Beta)
• OSOUTUZI
  Old-School UZI Executable Generator (In planning)
• OSOUTUZX
  Old-School UZIX Executable Generator (In planning)
• OSOUTMNX
  Old-School Minix Executable Generator (In planning)
• OSBASZ80
  Old-School BASIC Compiler for Z80 (In planning)
• OSBAS80
  Old-School BASIC Compiler for i80 (In planning)
• OSBAS86
  Old-School BASIC Compiler for i86 (In planning)
• OSCC0
  Old-School C Parser and Pre-Processor (Alpha)
• OSCC1
  Old-School C Syntax Analyzer (In planning)
• OSCCZ80
  Old-School C Compiler for Z80 (In planning)
• OSCC80
  Old-School C Compiler for i80 (In planning)
• OSCC86
  Old-School C Compiler for i86 (In planning)

File extensions

• .s: Old-School Assembler Source File
• .bas: Old-School BASIC Source File
• .c: Old-School C Source File
• .cc1: Old-School C Token File
• .cc: Old-School C Object File
• .obj: Old-School Generic Object File
• .lnk: Old-School Linked Object File

Tool Usage Steps

OSBASxxx --> OSASMxxx -\
             OSASMxxx --+--> OSLINK --> OSOUTxxx
             OSASMxxx -/

• OSASMxxx Gererates Object files from source files
• OSLINK Links Object files in one Linker Object File
• OSOUTxxx Converts Linker Object file to final executable

Test Machines

• 8080/Z80:
  openMSX Emulator: Gradient Expert Plus + DDX 3.0 Floppy Cartridge

• 8086:
  PC Pentium 100 with MS-DOS 6.22

Minimum Requirements

MS-DOS Distributions

MS-DOS 3.0 or compatible
192 KiB RAM
360 KiB Floppy Disk

CP/M or MSX-DOS

48 KiB TPA (64 KiB RAM) Floppy Disk

Distros

• distro/msxdos1.dsk:
  MSX-DOS 1 Distribution Disk (Bootable)
• distro/msxdos1alt.dsk:
  CP/M i80 Distribution Disk for MSX-DOS (Bootable)
• distro/msxdos2.dsk:
  MSX-DOS 2 Distribution Disk
• distro/msdosXXXX.img:
  MS-DOS Distribution Disk

Minimum Requirements for Development

• NASM
• (Smaller-C with 8086 target)[github.com/humbertocsjr/SmallerC]
• Z88dk
• GCC
• MTools

Ubuntu Development Env Install

Preparation script:

sudo apt install nasm build-essential mtools
sudo snap install --beta z88dk
git clone https://github.com/humbertocsjr/SmallerC.git
cd SmallerC
chmod +x ./configure
./configure
make 
sudo make install
cd ..
rm -R SmallerC

Old-School Generic Object File Format

All object files are composed of records, all following a single pattern described below:

Pos	Size	Description
000	0001	Reg Type
001	0001	Data Size
002	????	Data

The data field can be up to 255 bytes long.

TODO: Add Reg Type List

Old-School Assembler

This is a generic assembler framework, supporting multiple 8/16bit processors.

Common commands

• proc [PROCEDURE NAME]
  This command mark the start of a internal procedure/function, is used by the linker to filter used functions from unused ones in the final executable.
• endp
  This command mark the end of a procedure/function.
• use [PROCEDURE NAME]
  This command informs the linker which functions will be used by current function, not being necessary in the case of directly using the CALL command (It varies in each processor)
• cpu [CPU model]
  This command informs the target cpu of the source code.
• sector [CODE / DATA / BSS] This command tells which sector of the executable the next commands belong to.
• db [value1, value2, value3....] Output bytes directly to the final executable.
• dw [value1, value2, value3....] Output words (2 bytes) directly to the final executable.