HD6417615 Hitachi Semiconductor, HD6417615 Datasheet - Page 60

• Manufacturer Part Number: HD6417615
• Description: Hardware Manual
• Manufacturer: Hitachi Semiconductor

2.2.3
Byte immediate data is placed in an instruction code.
With the MOV, ADD, and CMP/EQ instructions, immediate data is sign-extended and operated in
registers as longword data. Immediate data accessed by the TST, AND, OR, and XOR instructions
is zero-extended and handled as longword data. Consequently, AND instructions with immediate
data always clear the upper 24 bits of the destination register.
Word or longword immediate data is not located in the instruction code; it should be placed in a
memory table. Use an immediate data transfer instruction (MOV) to refer the memory table using
the PC relative addressing mode with displacement.
2.2.4
This chip has three different types of data format that correspond to various instructions. These are
the fixed-point data format, the integer data format, and the logical data format.
The DSP type fixed-point data format has a binary point fixed between bits 31 and 30. There are
three types: with guard bits, without guard bits, and multiplication input; each with different valid
bit lengths and value ranges.
The DSP type integer data format has a binary point fixed between bits 16 and 15. There are three
types: with guard bits, without guard bits, and shift amount; each with different valid bit lengths
and value ranges. The shift amount of the arithmetic shift (PSHA) has a 7 bit range and can
express values from –64 to +63, but the actual valid values are from –32 to +32. In the same
manner, the shift amount of the logical shift has a 6 bit range, but the actual valid values are from
–16 to +16.
The DSP type logical data format does not have a decimal point.
The data format and valid data length are determined by the instructions and DSP registers.
Figure 2.7 shows the three DSP type data formats and binary point positions. The SuperH type
data format is also shown for reference.
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Immediate Data Format
DSP Type Data Formats