A51: DEFINING NEW INSTRUCTIONS WITH MACROS
Information in this article applies to:
I am using the M8051TBO from Virtual IP Group. This CPU has an additional instruction, DEC DPTR. The opcode is 0A5h but the Keil assembler does not directly support it.
Other IP cores like the Mentor M8051EW have additional instructions, too (Mentor uses opcode 0A5h for a MOVC @DPTR++,A instruction).
How can I use such instructions in my assembler programs?
To use chip-specific instructions, you may define a Macro that expands to the appropriate opcode. For example:
DEC_DPTR MACRO ; DEC DPTR instruction on M8051TBO DB 0A5H ; op-code ENDM MOVCI MACRO ; MOVC @DPTR++,A instruction on M8051EW DB 0A5H ; op-code ENDM
These macros may be used as if they were assembler instructions. For example:
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Last Reviewed: Sunday, October 29, 2006
of your data.