> On Jan 9, 2017, at 12:38 AM, Don North <no...@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. paul