SH7729R Datasheet, PDF (70/855 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer Super RISC engine Family/SH7700 Series

On the other hand, registers R2–R9 are also used for DSP data address calculation when DSP
extension is enabled (see figure 2.4). Other symbols that represent the purpose of the registers in
DSP type instructions is shown in [ ].
31
0
R0
General Registers (DSP mode enabled)
R1
R2 [As]
R3 [As]
R4 [As, Ax]
X or Y data transfer operation
R4, 5 [Ax]: Address register set for X data memory.
R8 [x]: Index register for address register set Ax.
R5 [As, Ax]
R6 [Ay]
R7 [Ay]
R8 [Ix, Is]
R9 [Iy]
R10
R11
R6, 7 [Ay]: Address register set for Y data memory.
R9 [Iy]: Index register for address register set Ay.
Single data transfer operation
R2−5 [As]: Address register set for memory.
R8 [Is]: Index register for address register set As.
R12
R13
R14
R15
Figure 2.4 General Purpose Registers (DSP Mode)
DSP type instructions can access X and Y data memory simultaneously. To specify addresses for
X and Y data memory, two address pointer sets are provided. These are:
R8[Ix], R4,5[Ax] for X memory access, and R9[Iy], R6,7[Ay] for Y memory access.
The symbols R2–R9 are used by the assembler, but users can use the register name (alias) to
indicate the purpose of the register in the DSP instruction. The coding in assembler is as follows.
Ix: .REG (R8)
Rev. 5.0, 09/03, page 24 of 806