ps.tmac

.nr _C \n(.C .cp 0 .cflags 8 \(an .char \[radicalex] \h'-\w'\(sr'u'\[radicalex]\h'\w'\(sr'u' .char \(mo \h'.08m'\(mo\h'-.08m' .char \(nm \h'.08m'\(nm\h'-.08m' .char \[parenlefttp] \[parenlefttp]\h'.016m' .char \[parenleftbt] \[parenleftbt]\h'.016m' .char \[parenleftex] \[parenleftex]\h'.016m' .char \[parenrighttp] \[parenrighttp]\h'.016m' .char \[parenrightbt] \[parenrightbt]\h'.016m' .char \[parenrightex] \[parenrightex]\h'.016m' .char \[ci] \v'-.25m'\h'.05m'\D'c .5m'\h'.05m'\v'.25m' .char \[sq] \h'.05m'\D'l .5m 0'\D'l 0 -.5m'\D'l -.5m 0'\D'l 0 .5m'\h'.55m' pic tests this register to see whether it should use \X'ps:...'
.nr 0p 1 .cp \n(_C