3.14 Accumulator Access

Accumulator can be accessed with File Register or Indirect Addressing, using any instruction which supports such addressing. However, it is recommended that the DSP instructions, LAC, SAC and SACR, be used to load and store the accumulators, since they provide sign-extension, shifting and rounding capabilities. LAC, SAC, and SACR instruction details are provided in Instruction Descriptions.

Note:
  1. For convenience, ACCAU and ACCBU are sign-extended to 32 bits. This provides the flexibility to access these registers using either Byte or Word mode (when File Register or Indirect Addressing is used).
  2. The OA, OB, SA or SB bit cannot be set by writing overflowed values to the memory-mapped accumulators using MOV instructions, as these Status bits are only affected by DSP operations.
  3. dsPIC33A SUAC, SAC and SLAC instructions to store ACCxU, ACCxH and ACCxL values respectively. Similarly, LUAC, LAC and LLAC instructions can be used to load values to ACCxU, ACCxH and ACCxL.