On Jan 9, 2017, at 12:38 AM, Don North <north at alum.mit.edu> wrote: On 1/8/2017 9:10 PM, Brent Hilpert wrote: 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.

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 <paulkoning at comcast.net> wrote: > >> On Jan 9, 2017, at 12:38 AM, Don North <north at alum.mit.edu> 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.