Re: Sundance or Warrior?

On Fri, 9 Nov 2001 13:48:15 -0500, "Omar Vega" <omar@techsource.com> wrote:

>Tailgunner was put out on a Vbeam board also. I'll have to check the
>strapping and number of ROMs when I get home though.

Tailgunner used the JEI (jump on external input) command to check the comparator
when reading the position of the joystick. Since the JMI (jump on minus), and
the JEI command are the same opcode, with the command being determined by the
JMI jumper, Tailgunner can not run on a board with this jumper in place.

FWIW: All the JMI jumper did was route the highest bit of the temporary
accumulator to the external input line, which allowed checking the sign bit of
the most recently accessed accumulator (A or B) using the JEI instruction. The
external input was sampled with a hardware latch (for debouncing), which caused
the test results to be delayed by one instruction. A bit weird, and this is why
you see all sign test instructions (JMI's) proceeded with a NOP to allow the
minus flag to "latch", before testing it -- a bit of a pain to emulate
correctly.

Probably more than you ever wanted to know about that jumper huh?

-Zonn

>
>
>----- Original Message -----
>From: "Zonn" <zonn@zonn.com>
>To: <vectorlist@synthcom.com>
>Sent: Friday, November 09, 2001 12:46 PM
>Subject: Re: VECTOR: Sundance or Warrior?
>
>
>> On Fri, 09 Nov 2001 10:29:31 -0600, tom mcclintock <tomm@mgcap.com> wrote:
>>
>> >Star Hawk, Space War(s), or Barrier. I'd guess Space War if the board is
>> >marked Vectorbeam. Sundance and Warrior use four EPROMs BTW. Then again,
>> >it could be a Scramble...
>>
>> Well it's not a Space War, the JMI jumper is installed -- though Space War
>will
>> run with or without this jumper it was never installed on a Space War
>(well, ok,
>> *probably* never installed... this is the jumper above the ROMS). That
>and the
>> all dip switches are installed, Space War used many of the DIP switch
>inputs
>> for it's many front panel buttons.
>>
>> I'd guess Star Hawk, though I suppose it could be a Barrier. Did they make
>> enough Barrier's to have a ROM mask made? It's a Star Hawk. (Or a
>Scramble /
>> Oops! ;^)
>>
>> -Zonn

---------------------------------------------------------------------------
** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
** message body to vectorlist-request@synthcom.com. Please direct other
** questions, comments, or problems to neil@synthcom.com.
Received on Fri Nov 9 11:16:08 2001