SH7729R Datasheet, PDF (71/855 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer Super RISC engine Family/SH7700 Series

The name Ix is the alias for R8. Other aliases are as follows.
Ax0: .REG
Ax1: .REG
Ix: .REG
Ay0: .REG
Ay1: .REG
Iy: .REG
As0: .REG
As1: .REG
As2: .REG
As3: .REG
Is: .REG
(R4)
(R5)
(R8)
(R6)
(R7)
(R9)
(R4) ; This is optional, if another alias is required for single data transfer.
(R5) ; This is optional, if another alias is required for single data transfer.
(R2)
(R3)
(R8) ; This is optional, if another alias is required for single data transfer.
2.1.2 Control Registers
The SH7729R has 8 control registers: SR, SSR, SPC, GBR, VBR, RS, RE, and MOD (figure 2.5).
SSR, SPC, GBR and VBR are the same as the SH-3 registers.
In SR, there are six additional control bits: RC[11:0], RF0, RF1, DMX, DMY and DSP. Bits
DMX, DMY, RC[11:0], and RF[1:0] can be modified in privileged mode, privileged DSP mode,
and use DSP mode. DMX and DMY are used for modulo addressing control. If DMX is 1, the
modulo addressing mode is effective for the X memory address pointer, Ax (R4 or R5). If DMY is
1, the modulo addressing mode is effective for the Y memory address pointer, Ay (R6 or R7).
However, both X and Y address pointers cannot be operated in modulo addressing mode even
though both DMX and DMY bits are set. The case where DMX = DMY = 1 is reserved for future
expansion. Modulo addressing is available for X and Y data transfer operations (MOVX and
MOVY), but not for a single data transfer operation (MOVS).
RF1 and RF0 hold information on the number of repeat steps, and are set when a SETRC
instruction is executed. When RF[1:0] = 00, the current repeat module consists of one instruction
step. RF[1:0] = 01 means two instruction steps, RF[1:0] = 11 means three instruction steps, and
RF[1:0] = 10 means the current repeat module consists of four or more instructions.
Although RC[11:0] and RF[1:0] can be changed by a store/load to SR, use of the dedicated
manipulation instruction SETRC is recommended.
Rev. 5.0, 09/03, page 25 of 806