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RTEMS 4.6.99.3 On-Line Library


CPU Model Dependent Features Floating Point Unit

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1.3: Floating Point Unit

The Texas Instruments C3x/C4x family makes little distinction between the various cpu registers. Although floating point operations may only be performed on a subset of the cpu registers, these same registers may be used for normal integer operations. as a result of this, this port of rtems makes no distinction between integer and floating point contexts. The routine _CPU_Context_switch saves all of the registers that comprise a task's context. the routines that initialize, save, and restore floating point contexts are not present in this port.

Moreover, there is no floating point context pointer and the code in _Thread_Dispatch that manages the floating point context switching process is disabled on this port.

This not only simplifies the port, it also speeds up context switches by reducing the code involved and reduces the code space footprint of the executive on the Texas Instruments C3x/C4x.


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