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Document BusHandler interface.

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Thomas Harte 2022-05-13 10:59:36 -04:00
parent 0d81992f6a
commit 7a2fd93d08
1 changed files with 22 additions and 1 deletions
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23
InstructionSets/M68k/Executor.hpp
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@ -28,11 +28,32 @@ enum class FunctionCode {
InterruptAcknowledge = 0b111,
};
/// The Executor is templated on a class that implements bus handling as defined below;
/// the bus handler is responsible for all reads and writes, and will also receive resets and
/// interrupt acknowledgements.
///
/// The executor will provide 32-bit addresses and act as if it had a 32-bit data bus, even
/// if interpretting the original 68000 instruction set.
struct BusHandler {
/// Write @c value of type/size @c IntT to @c address with the processor signalling
/// a FunctionCode of @c function. @c IntT will be one of @c uint8_t, @c uint16_t
/// or @c uint32_t.
template <typename IntT> void write(uint32_t address, IntT value, FunctionCode function);
/// Read and return a value of type/size @c IntT from @c address with the processor signalling
/// a FunctionCode of @c function. @c IntT will be one of @c uint8_t, @c uint16_t
/// or @c uint32_t.
template <typename IntT> IntT read(uint32_t address, FunctionCode function);
/// React to the processor programmatically strobing its RESET output.
void reset();
int acknowlege_interrupt(int);
/// Respond to an interrupt acknowledgement at @c interrupt_level from the processor.
/// Should return @c -1 in order to trigger autovectoring, or the appropriate exception vector
/// number otherwise.
///
/// It is undefined behaviour to return a number greater than 255.
int acknowlege_interrupt(int interrupt_level);
};
/// Ties together the decoder, sequencer and performer to provide an executor for 680x0 instruction streams.