Identifiers or symbol names may be as long as 512 characters. The first character of the name must be alphabetic; remaining characters may be alphanumeric or an underscore character (_). By default, upper- and lowercase characters are distinct unless case-sensitivity is turned off in the Freescale DSP Assembler settings panel.
The identifiers listed in the following table are reserved for the assembler. These names identify the Freescale DSP registers.
| X | A | PC |
| X0 | A0 | M01 |
| X1 | A1 | N |
| Y | A2 | SP |
| Y0 | B | MR |
| Y1 | B0 | CCR |
| R0 | B1 | SR |
| R1 | B2 | OMR |
| R2 | LC | SSH |
| R3 | LA |