4 Jan
2007
4 Jan
'07
7:26 a.m.
On Wed, 3 Jan 2007, Dave Dunfield wrote:
> Has anyone extracted images of the Read Only
Storage
> for the IBM 5100/5100 desktop computers? I haven't
I've extracted the first of the two Exec ROS', the one containing all the
monitor and I/O routines. I'm in the progress of disassembling and
commenting the code. I've also disassembled several IBM utility programs,
e.g. TDTCOPY, DDCOPY, SIO8BIT, DIAG DCP and so on.
This for example is the beginning of the Tape I/O supervisor routine:
; ***************************
; Device E (Tape) I/O Routine
; ***************************
7F00 216C MOVE R1, $D8 ; Vector table for I/O routines
7F02 A13B ADD R1, #$3C ; Vector to device F
7F04 D718 MOVE R7, (R1)
7F06 0F33 INC2 R15, R3
7F08 6EF0 MOVB R14, (R15)+ ; IOCB_Cmd
7F0A 6DF6 MOVB R13, (R15)--- ; IOCB_Flags
7F0C CE0B SNZ R14
7F0E A00B BRA $7F1C ; "Sense" command
7F10 8C30 LBI R12, #$30
7F12 8103 LBI R1, #$03
7F14 CE10 SLE R14, R1 ; Read or Write ?
7F16 A007 BRA $7F20 ; No
7F18 CDC6 SBC R13, R12
7F1A A02B BRA $7F48 ; Bit 2 or 3 set
7F1C 2807 MOVE R8, $0E ; R7L0, contains vector
7F1E 2056 JMP ($00AC) ; Do I/O and return to caller
[...]
> seen any mention of it anywhere, nor any
simulators.
> Has anyone worked on this? Seems like it should be doable
> and worthwhile. Though, it might be necessary to build
> hardware to read out the ROS contents -- I don't think the
> 5100 provides programmatic access to the PALM object code for
> the 360 and S/3 emulators, just the BASIC and APL code.
> Does that sound right?
Yes. The 5110 can only access the following ROS':
Common ROS
BASIC ROS
APL ROS
and maybe Diskette Sort (haven't tried yet)
These ROS' are accessed as an I/O device. You write two PUTB instructions
to device 1, MSB of the ROS address first, then LSB. Then you can read the
contents of this ROS with consecutive GETBs (the second GETB automatically
increments the ROS address by 1; ROS address is given as word address!).
I've read these ROS' from my 5110 model 1.
The Executable ROS is only accessible by the processor during an
instruction fetch cycle... and by the graphics adapter while -POR is
active!
BTW I haven't found any 360 / S/3 emulator yet. Both BASIC and APL ROS
don't contain any code I recognize.
I'd be VERY interested if some progress can be
made on this.
Really? Until now nobody have had any interest in neither a Kermit for the
5110 nor an Infocom interpreter (both written in assembly).
I have a (BASIC only) 5100 that has a failure of the
non-executable
ROS ...
Of what non-executable ROS? There are several. Do you also have the
Diskette Sort feature (additional ROS card)?
So far I've not been able to dig up any
significant technical information,
You haven't searched for that information, have you? Do you know my site?
It's still not complete, though, as I'm learing more and more while
disassembling programs and playing with different bits...
Christian