17 ears ago I wrote autoconf that enabled DOS users to boot multiple configurations without any menus or pause. I admit, I copied the original source from SVM, but ended up working on it for a very long time and extending the features for at least two or three years. The name was unfortunate since GNU already had an autoconf, but I was completely unfamiliar with the *nix side of the world since all I had was a 386 PC. Autoconf went on to be widely used, especially in Europe until DOS 6.2 which introduced multiple configurations that were “good enough”. I spent a month writing a converter from DOS configurations into Autoconf configurations, but it was too late, Microsoft pushed me out of the multi-boot market by embedding a crappier default implementation into the operating system. Anyway, I forgive you, Bill.
Here’s the code that let you declare DEVICE=something.sys in your config.sys file. I included the juiciest commented parts below. The preamble is already priceless.
;----------------------------------------------------------------------------
; This code is so simple I just couldn't beleive it. So forget about all
; books on assembler, cause this DOES ALWAYS WORK and is the shortest way
; to do it!
;----------------------------------------------------------------------------
I used macros stolen from someone’s 3D rendering engine’s source code to avoid typing push and pop too many times. That someone was probably sitting next to me in the basement of Infomaniak in Geneva. ASM recursive macros must blow your mind!
pushx macro r1, r2, r3, r4, r5, r6, r7, r8 ;that's a usefull macro
ifnb <r1> ;stolen it from the source
push r1 ;of a 3D vector engine...
pushx r2, r3, r4, r5, r6, r7, r8 ;pushx + 8 registers max
endif
endm ;assembled depending from
;pushed quantity
popx macro r1, r2, r3, r4, r5, r6, r7, r8
ifnb <r1>
pop r1
popx r2, r3, r4, r5, r6, r7, r8
endif
endm
The following seems pretty magical to me right now. Oh yeah, otherwise it STUCKS!
ORG 0000h ;INDESPENSABLE, SINCE OTHERWISE IT STUCKS
driver_suiv dw -1 ;ALL THIS IS NECESSARY FOR
dw -1 ;DOS COMPATIBILITY AND
attribut dw 8004h ;CONFLICT AVOID, if you remove
req dw offset sys_request ;it will stuck the machine
run dw offset init ;CRAZY DOS!!!!
nom_device db 'NUL '
Who uses DOS 3.2, seriously?
lds bx,dword ptr cs:[req_ofs] ;verify the DOS rubbish
mov word ptr [bx+14],0 ;version -> stay resident
mov word ptr [bx+16],cs ;or not
push bx ;who uses DOS 3.2 ????
mov ah,30h
int 21h ;HAS TO STAY RESIDENT BEFORE
pop bx ;DOS 3.2, cause otherwise
cmp al,3 ;IT WILL GO CRAZY
Finally …
END ;oh finally the end...
The entire source for this gem is here. And I’ve published the complete autoconf source here on Github.