4.4.5. MCR

This function is called when an MCR instruction is recognized for a coprocessor. If the requested coprocessor register does not exist or cannot be written to, the function must return ARMul_CP_CANT.

Syntax


unsigned MCR(void *handleint type, ARMword instr, ARMword *data)

where:

handle

is the handle from ARMulif_InstallCoprocessorV5.

type

is the type of the coprocessor access. This canbe one of:

ARMul_CP_FIRST

indicates that this is the first time the coprocessor model has been called for this instruction.

ARMul_CP_BUSY

indicates that this is a subsequent call, after the first call was busy-waited.

ARMul_CP_INTERRUPT

warns the coprocessor that the ARM is about to service an interrupt, so the coprocessor must discard the current instruction. Usually, the instruction will be retried later, in which case the type will be reset to ARMul_CP_FIRST.

ARMul_CP_DATA

indicates valid data is included in data.

instr

is the current opcode.

data

is a pointer to the data being transferred to the coprocessor.

Return

The function must return one of:

  • ARMul_CP_DONE, to indicate that the coprocessor operation is complete

  • ARMul_CP_BUSY, to indicate that the coprocessor is busy

  • ARMul_CP_CANT, to indicate that the instruction is not supported, or the specified register cannot be accessed.

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