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Hitachi Embedded Workshop User Manual
151
2.7
H8S/2600 CPU Specific Functions
MAC Instruction: The multiplication/accumulation operation (MAC instruction) can be performed on the
H8S/2600 CPU. In this instruction, a saturation and non-saturation operations are selectable. The
simulator/debugger determines the operation with a value of bit 7 (hereafter called as the MACS bit) in the
SYSCR register of internal I/O.
MACS bit 0: Non-saturation operation
MACS bit 1: Saturation operation
EXR Register: The EXR register can be used on the H8S/2600 CPU. It is also possible to set the enable or
disable of this register. The simulator/debugger determines the operation with a value of bit 5 (hereafter called as
the EXR bit) in the SYSCR register of internal I/O.
EXR bit 0: EXR disabled
EXR bit 1: EXR enabled
The SYSCR address is set in [SYSCR Address] in the [Simulator System] dialog box.
Note:
Set the SYSCR address in the internal I/O. Note that the simulator/debugger determines the MACS bit as
0 (non-saturation) and the EXR bit as 0 (EXR disabled) when the SYSCR address is set other than the
internal I/O.
For details, refer to section 4.21.1, Simulator System Dialog Box.
2.8
Control Registers
The H8S/2600 series support the SYSCR (system control register) as the control register mapped to the memory.
It enables multiplication/accumulation operation, user program simulation for EXR accessing, and debugging.
The SYSCR address is set in [SYSCR Address] in the [Simulator System] dialog box. For modifying or
displaying the control register, use the [IO] window.
For details, refer to section 4.21.1, Simulator System Dialog Box, or section 4.5, Viewing the I/O Memory.