Datasheet

RX610 Group 2. CPU
R01DS0097EJ0120 Rev.1.20 Page 29 of 84
Feb 20, 2013
(8) Floating-Point Status Word (FPSW)
The floating-point status word (FPSW) indicates the results of floating-point operations.
When an exception handling enable bit (Ej) enables the exception handling (Ej = 1), the corresponding Cj flag indicates
the source of the exception within the exception handling routine. If the exception handling is masked (Ej = 0), check the
Fj flag at the end of a series of processing whether an exception is generated or not. The Fj flag is the accumulation type
flag (j = X, U, Z, O, or V).
(9) 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.