On 2017-Jan-09, at 6:27 AM, Pete Lancashire wrote: > wow ... the memories ... someday I've got to get a PDP-11 again :-). > > had most of the opcodes memorized, for a story .... > > Had a coworker who played the piano, he could enter/patch code from > the 11/35's panel from memory so fast all you saw was a blur. > > When we replacing the 11/35's with 11/34A he hated it. > > -pete > > On Mon, Jan 9, 2017 at 6:13 AM, Paul Koning <[email protected]> wrote: >> >>> On Jan 9, 2017, at 12:38 AM, Don North <[email protected]> wrote: >>> >>> On 1/8/2017 9:10 PM, Brent Hilpert wrote: >>>> OK, what was the standard (if there was one) number-base syntax for PDP-11 >>>> assembler? >>>> >>>> Despite all the PDP-11 assembly info on web sites, this seems to be a >>>> buried bit of info. >>>> One assembler doc uses a prefix of "&o", another specifies octal as >>>> default and prefix of zero for decimal (opposite of the common C-derived >>>> standard . . great). >>>> >>>> Is this for example standard?: >>>> >>>> BIT #&o200, @#&o177564 ; test 2^7 bit at address >>>> octal 177564 >>>> >>>> (I'm just trying to make some written commentary consistent with common >>>> policy.) >>>> >>>> >>> MACRO11 Language Manual v5.5 section 6.4 >>> >>> All numbers are octal radix, unless the default radix is changed via the >>> .RADIX N directive (N can be 2, 8, 10, or 16). N blank resets the radix to >>> octal. >>> >>> So 0100, 100 would be octal 100, decimal value 64. >>> >>> Any number followed by a period (decimal point) is forced to be base 10. >>> >>> So 100. would be decimal 100, octal 144. >>> >>> Prefix operators ^B (binary), ^O (octal), ^D (decimal), ^X (hexadecimal) >>> force the following digits/characters to the designated radix. >>> >>> So ^B101000 == ^O50 == ^D40 == ^X28 all represent the same value (decimal >>> 40.) irrespective of the current .RADIX N setting. >> >> I don't remember ^X. Other ways to specify numeric values is with prefix ' >> (single quote) for a single byte value, i.e., 'x is the ASCII code for >> character x. Similarly, "xy is a 16 bit value for the two-character >> sequence xy (little endian). And ^Rxyz is the RAD50 coded value for the >> three characters xyz. >> >> &o doesn't match anything I've ever seen, not even in the wildly different >> world of Unix.
So the answer is, by modern expectations the old standard would be ambiguous or misleading. I guess I should just comment it.
