RX630_15 Datasheet, PDF (54/156 Pages) Renesas Technology Corp – Renesas MCUs

RX630 Group
2. CPU
2.3 Register Associated with DSP Instructions
(1) Accumulator (ACC)
The accumulator (ACC) is a 64-bit register used for DSP instructions. The accumulator is also used for the multiply and
multiply-and-accumulate instructions; EMUL, EMULU, FMUL, MUL, and RMPA, in which case the prior value in the
accumulator is modified by execution of the instruction.
Use the MVTACHI and MVTACLO instructions for writing to the accumulator. The MVTACHI and MVTACLO
instructions write data to the higher-order 32 bits (bits 63 to 32) and the lower-order 32 bits (bits 31 to 0), respectively.
Use the MVFACHI and MVFACMI instructions for reading data from the accumulator. The MVFACHI and MVFACMI
instructions read data from the higher-order 32 bits (bits 63 to 32) and the middle 32 bits (bits 47 to 16), respectively.
R01DS0060EJ0160 Rev.1.60
May 19, 2014
Page 54 of 154