"Joe Morris" <
j.c.m...@verizon.net> writes:
> "Louis Krupp" <lkr...@nospam.pssw.com.invalid> wrote:
>> Ken Wheatley <
k...@birchanger.com> wrote:
>>>On 2012-05-18 14:38:41 +0000, Peter Grange said:
>
>>>> Clip from BBC "Tomorrow's World" in 1969. Can't place the hardware,
>>>> but what's coming out of the printer looks suspiciously like a crash
>>>> dump...
>>>>
http://www.retronaut.co/2011/08/new-banking-tomorrows-world-1969/
>
>>>Is it Burroughs?
>
>> An early pre-release B6500, maybe. I know Burroughs was still doing
>> cross-compliations of the MCP in 1969. The Conrac (?) displays look
>> familiar. If Joe says the dump contains instructions, then it
>> probably does. Hex A7 is a B6500 RETN (I looked it up), hex 92 is an
>> LNOT. The Mark Stack (AE) ... Enter (AB) sequence would be a
>> give-away, but at the moment, I don't see any of those.
>
> Looking at the dump, I'll call it certain that it's a dump of an S/360 (or
> compatible machine) program. We see only about 11 bytes of data on each
> line, but some examples:
>
> 2C722: MVC B1B(A,8),?C8(A) /move 8 characters
Move 8 would be:
MVC B1B(8,R10),C8(R10)
Of course if you see:
D208AB1BA0C8
^^
That's move 9 characters.
> B 0B?(A) /unconditional branch
> 2C740: BNZ (or BNE) 080(A) /branch on nonzero or unequal
> MVC B0B(A,8),BCB(A)
> B ???
> 2C760: CLI 818(A),X'00' /compare one byte of memory
> BE 0FA(A) /branch if equal
> LA 1,31?(A) /load address to register
> 2C782 has the character string I quoted - in EBCDIC, not ASCII
> 2C7A4: XC 808(A,8),808(A) /exclusive OR 8 bytes memory-to-memory
Same here.
> BZ ???(?)
> 2C7C0: XR 4,4 /exclusive OR register-to-register
>
> Fragments, but each one is self-consistent, and all of the base registers
> refer to R10. (Using exclusive OR was a common way of testing a register or
> field for zero or nonzero status.)
The above XR clears R4 to zero.
The operation sets the condition code but there's no "test" involved,
the result is always zero.
--
Dan Espen