The S12Z version of as recognizes the following options:
You can use the ‘-mreg-prefix=pfx’ option to indicate that the assembler should expect all register names to be prefixed with the string pfx.
For an explanation of what this means and why it might be needed, see Register Notation.
The ‘-mdollar-hex’ option affects the way that literal hexadecimal constants are represented. When this option is specified, the assembler will consider the ‘$’ character as the start of a hexadecimal integer constant. Without this option, the standard value of ‘0x’ is expected.
If you use this option, then you cannot have symbol names starting with ‘$’. ‘-mdollar-hex’ is implied if the ‘--traditional-format’ (see Compatible Output: --traditional-format) is used.