Interrupt handling
Posted: 30 Dec 2007 16:43
I psoted this in form of a question some time ago but received no reply, therefore I decided to rephrase it as a couple of suggestions:
1: Add a directive that instructs the compiler not to push&pop certain registers when an interrupt occurs. This is similar to how register handling is done on VAX, for those of you who're familar with VAX assembly
Why woudl this be useful ? Pushing and popping entire working register array takes plenty of cycles - sometiems it takes to long. If user could instruct the compiler not to push&pop registers that aren't used in interrupt handler, valuable cycles would be saved.
Something along the lines of {$MASK W9, W11, W12} would instruct the compiler not to generate push/pop pairs for registers W9, W11 and W12.
2: Add the option to implement interrupt handlers solely in assembly (short of RETFIE, of course). This is directly related to my first suggestion; if none of the registers are to be saved this would allow interrupt handler to contain only assembly code, allowing more efficient interrupt handlers for time-critical applications.
1: Add a directive that instructs the compiler not to push&pop certain registers when an interrupt occurs. This is similar to how register handling is done on VAX, for those of you who're familar with VAX assembly
Why woudl this be useful ? Pushing and popping entire working register array takes plenty of cycles - sometiems it takes to long. If user could instruct the compiler not to push&pop registers that aren't used in interrupt handler, valuable cycles would be saved. Something along the lines of {$MASK W9, W11, W12} would instruct the compiler not to generate push/pop pairs for registers W9, W11 and W12.
2: Add the option to implement interrupt handlers solely in assembly (short of RETFIE, of course). This is directly related to my first suggestion; if none of the registers are to be saved this would allow interrupt handler to contain only assembly code, allowing more efficient interrupt handlers for time-critical applications.