Differences From H8/300 Cpu; Differences From H8/300H Cpu - Hitachi H8S/2646 Hardware Manual

In addition, there are differences in address space, CCR and EXR register functions, power-down
modes, etc., depending on the model.
2.1.3

Differences from H8/300 CPU

In comparison to the H8/300 CPU, the H8S/2600 CPU has the following enhancements.
• More general registers and control registers
 Eight 16-bit expanded registers, and one 8-bit and two 32-bit control registers, have been
added.
• Expanded address space
 Normal mode* supports the same 64-kbyte address space as the H8/300 CPU.
 Advanced mode supports a maximum 16-Mbyte address space.
Note: * Not available in the H8S/2646 Series.
• Enhanced addressing
 The addressing modes have been enhanced to make effective use of the 16-Mbyte address
space.
• Enhanced instructions
 Addressing modes of bit-manipulation instructions have been enhanced.
 Signed multiply and divide instructions have been added.
 A multiply-and-accumulate instruction has been added.
 Two-bit shift instructions have been added.
 Instructions for saving and restoring multiple registers have been added.
 A test and set instruction has been added.
• Higher speed
 Basic instructions execute twice as fast.
2.1.4

Differences from H8/300H CPU

In comparison to the H8/300H CPU, the H8S/2600 CPU has the following enhancements.
• Additional control register
 One 8-bit and two 32-bit control registers have been added.
• Enhanced instructions
 Addressing modes of bit-manipulation instructions have been enhanced.
 A multiply-and-accumulate instruction has been added.
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