Renesas HD6417641 用户手册
Section 2 CPU
Rev. 4.00 Sep. 14, 2005 Page 42 of 982
REJ09B0023-0400
DSR is assigned as a system register and the following load/store instructions are provided:
STS DSR,Rn;
STS.L DSR,@-Rn;
LDS Rn,DSR;
LDS.L @Rn+,DSR;
When DSR is read by an STS instruction, the upper bits (bits 31 to 8) are all 0.
2.2 Data
Formats
2.2.1
Register Data Format (Non-DSP Type)
Register operands are always longwords (32 bits) (figure 2.9). When the memory operand is only
a byte (8 bits) or a word (16 bits), it is sign-extended into a longword when loaded into a register.
a byte (8 bits) or a word (16 bits), it is sign-extended into a longword when loaded into a register.
31
0
Longword
Figure 2.9 Longword Operand
2.2.2 DSP-Type
Data
Formats
This LSI has several different data formats that depend on the instruction. This section explains
the data formats for DSP type instructions.
the data formats for DSP type instructions.
Figure 2.10 shows three DSP-type data formats with different binary point positions. A CPU-type
data format with the binary point to the right of bit 0 is also shown for reference.
data format with the binary point to the right of bit 0 is also shown for reference.
The DSP-type fixed point data format has the binary point between bit 31 and bit 30. The DSP-
type integer format has the binary point between bit 16 and bit 15. The DSP-type logical format
does not have a binary point. The valid data lengths of the data formats depend on the instruction
and the DSP register.
type integer format has the binary point between bit 16 and bit 15. The DSP-type logical format
does not have a binary point. The valid data lengths of the data formats depend on the instruction
and the DSP register.