From Assembler

2.4.3 Values in expressions
The following forms of simple values may be used.
nnn - Decimal number, eg: 21
nnnD - "" "": 21d
nnnT - "" "": 21t
$nnn - Hexidecimal number, eg: $15
nnnH - "" "": 15h
%nnn - Binary number, eg: %10101
nnnB - "" "": 10101b
@nnn - Octal number, eg: @177
nnnO - "" "": 177o
nnnQ - "" "": 177q
'cc' - ASCII characters, eg: 'A'
<label> - Value of a label from symbol table.
* - Value of current program counter.
$ - "" ""

From Compiler

3.1 Constants
The following forms of constants are supported by the compiler:
<num> - Decimal number (0 - 65535)
0<num> - Octal number (0 - 0177777)
0x<num> - Hexidecimal number (0x0 - 0xffff)
'<char>' - Character (1 or 2 chars)
"<string>" - Address of literal string.
The following "special" characters may be used within character
constants or strings:
\n - Newline (line-feed) (0x0a)
\r - Carriage Return (0x0d)
\t - Tab (0x09)
\f - Formfeed (0x0c)
\b - Backspace (0x08)
\<num> - Octal value <num> (Max. three digits)
\x<num> - Hex value <num> (Max. two digits)
\<char> - Protect character <char> from input scanner.

Not sure how to find the predefined macro that you refer to.

Jon