RTools

This is MS-DOS tools for linking RDF/RDL files. While playing with small compilers, I noticed one problem for all beginners. It lacks runtime-libraries and linkers support.

I investigate the OBJ/OMF format and found it too complicated. AOUTB has no segment memory support. COFF and ELF are also complex and solve problems non-relevant to MS-DOS.

By chance, I meet the RDOFF2 format from NASM - a beautiful and simple format for object modules.

This repository contains tools for working with RDOFF2 (and source code) to help you build small compilers.

RDF - NASM builtin format RDOFF2 for object files. Different version of Nasm works different with this files. So, I strongly advise to use NASM version 0.98.39. See DOC\RDOFF2.TXT and source code.

RDL - Again, NASM-format but for libraries.

• nasm - version 0.98.39, just recompiled for MS-DOS (no DPMI) with RDF support (by default - is disabled). No other changes.
• rdfdump - dump utility
• rlib - library manager
• rlink - linker itself

RLINK

RLINK can generate huge files. To speed up RLINK - point your TMP/TEMP directory to ramdrive. So, don't be confused with dos 16-bit application - RLINK known how to handle more then 64kb and 640kb :).

Supported output formats

• COM - simple MS-DOS .com file
• MZS - MS-DOS exe, small memory model (CS = code, DS = data,bss,stack)
• MZL - MS-DOS exe, large memory model (each rdf have own CS, DS and BSS segment)
• ADAM - DOS32 Extender.
• LX - OS/2 and DPMI exe file.
• PE - DOS PE32 file (PE32 without imports).
• QLB - QuickBASIC Quick Library (.QLB), large memory model, see below.
• RDF - Linked rdf into one code-segment (like a .com, but with zero offset and name). Could be used as DLL. If you load code segment at ????:0000 - you don't need process relocations. And, as bonus, you can use symbol table.

Builtin stubs and extenders

• Simple stub (will write something like "This is dpmi exe!"). Can be used with HX-DOS Extender or with LX format (if you want bind other DOS-Extender).
• Loader DOS32 Extender (for ADAM)
• ZRDX DOS-Extender (for LX)
• Loader HX-DOS Extender (for PE).

If you need viewer for RDF, please visit to https://github.com/DosWorld/objview

"Make" utility available at https://github.com/DosWorld/smallmake

QLB - QuickBASIC Quick Library

rlink qlb /o=NAME.QLB A.RDF B.RDF links rdf files into a Quick Library for QuickBASIC 4.5 (QB /L NAME.QLB). It was tested with QuickBASIC 4.0 and 4.50 (QB.EXE); QBasic (QBASIC.EXE, MS-DOS 5/6) is a different product and does not load Quick Libraries (no /L option). The library is standalone: no BQLB45.LIB or Microsoft linker is needed. See TEST\QLB for an example, DOC\QLB.MD for the format description and DOC\QLBRT.MD for what QuickBASIC requires.

• Every module from the command line is linked (not only modules reachable from the entry-point). Each rdf gets its own code, data and bss segment, as in MZL.
• All exported symbols from code segment go into the library, and BASIC finds them by name (DECLARE SUB name () / CALL name), names are case-insensitive. Use A-Z, 0-9 and _.
• RLINK adds a small precompiled runtime (SRC\QBRT.ASM, source of the table in RLOQBE.PAS), which QuickBASIC calls through b_ULVars. Selector 0Ah (find procedure) is solved by the runtime with a hash code table and the names, created by RLINK and kept after the runtime code, selector 10h (find common) is handled by the runtime too. For all other selectors (start-up, shut-down, ...) the runtime calls the entry-point (/entry, default start), so the entry-point is the start-up/shut-down hook. It is a Pascal style far procedure: the selector is the word parameter on the stack, the procedure removes it (retf 2), the selector is also in CX. Without any work to do the entry-point is just retf 2.
• Names. The CODE table of the QB header lists every exported name in the spelling of the object (/nonames leaves it empty). The runtime of the library finds a routine like the runtime of Microsoft's libraries: QuickBASIC sends the name as written and, for a CDECL declaration, the flag DX = 0040h; the runtime then looks for _ + name (DECLARE FUNCTION foo CDECL finds the symbol _foo). It also frees the temporary string that holds the name (service 26 of QuickBASIC), otherwise QuickBASIC hangs after a dozen lookups. See DOC\QLBRT.MD.
• Imports. A module may extern the names of QuickBASIC itself: services (B$RUNERR, B$STDALC ...) and variables (b_errnum, b_ULSymSeg ...). RLINK resolves them with thunks and offsets in the QB data segment, nothing else is needed. The list and the rules are in DOC\QLB-IMP.MD (section 9), the test is TEST\QLB\IMPORT.ASM.
• Only 16-bit relocations. Library data is mapped into QuickBASIC data segment at offset 3360h, the library is built for the QuickBASIC 4.5 (QB.EXE) layout.
• TEST/QLB21: prototype that loads a QLB from a DOS program with INT 21h AH=4Bh AL=01h (see DOC/QLB21.MD).
• Size: every RDF is its own segment set, so the code, data and bss of one RDF are each limited to 64 KB; the library as a whole can be larger (up to about 1 MB). Tested: 80 KB library of two 40 KB modules in QuickBASIC 4.50.

How to use

See MAKEFILE in TEST directory.

Dependencies

Requires System2 library:

https://github.com/DosWorld/libsystem2

Build

You need Turbo Pascal, System2 library and "make" in path. Just type:

    cd src
    make

License

NASM version 0.98.39 binaries distributed with own different license and copyright-holders (see DOC\NASMLIC.TXT, GNU LGPL).

MIT License