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Applies to: C51 C Compiler
Information in this article applies to:
Can I use the high speed multiply/divide unit of the Infineon 80C517 in my main program and in an interrupt routine?
No. The 517 multiply/divide unit does not allow recursive use of the MDU indexes. The overhead of saving and restoring these registers would eliminate the advantage of the MDU. Therefore, the MDU may be used in the main program or in an interrupt, but not both.
If you must use the MDU in an interrupt and in your main code, you must disable interrupts in your main code when you multiply and divide, and restore interrupts when your math routines are finished. This ensures that interrupts do not run while you access the MDU of the 517.
Article last edited on: 2005-09-28 18:23:20
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