Monthly Archives: August 2018

QL-SD teaser

The QL-SD driver seems to be finished (note that it currently doesn’t work with the MiST FPGA board, but there are no more known problems with either the original QL hardware or the MiSTer FPGA machine).

Now the boring part has begun, which means hours of reading tax related stuff (selling stuff internationally is hard!), writing/updating the manual, preparing an order page, preparing shipping labels, etc. I really don’t enjoy this part of the process.

Anyway, as a short teaser, the hardware does exist now in some quantities:

I will probably open the order page publicly starting September, after my holiday.

QDOS: To LRESPR or not

Update: the old code had a bug if the EXE was made resident using the HOT_RES keyword (thanks to Jan Bredenbeek for pointing it out), updated code below.

Today I’ve had a short discussion about creating a QDOS executable that can both be LRESPRed (to install a thing) and EXecuted (to, erm, execute it). One important detail is that LRESPR must only work in the main BASIC, as otherwise the system will crash once the daughter BASIC is terminated. There are several ways to do it, but I’d like to share mine:

base    bra.s   start
        nop
        nop
        dc.w    $4AFB
        dc.w    4
        dc.b    'Test'

start
; Trick: on an EXE call a6 must point to either a BRA ($60) or JMP ($4E).
; both have bit 6 set ($40). On Basic a6 points to the MSB of sb_buffb.
; Bit 6 will never be set as long as QLs have less than 1GB of RAM 🙂
        btst    #6,(a6)
        beq.s   lrespr                  ; Definitely LRESPR
        cmp.w   #$4afb,6(a6)            ; This check is somewhat optional...
        beq.s   job_start               ; but in case QLs ever have >1GB... 🙂

lrespr
        moveq   #sms.info,d0
        trap    #1
        tst.l   d1                      ; Job ID = main BASIC
        beq.s   basic_start

; LRESPRed from daughter SBASIC/MultiBasic
        moveq   #err.nimp,d0
        rts

; LRESPred from main BASIC
basic_start
;       ...
        moveq   #0,d0
        rts

; EXECed as normal job
job_start
;       ...