Accumulator Catastrophic Overflow

If the SATA (CORCON[7]) and/or SATB (CORCON[6]) bits are not set, then no saturation operation is performed on the accumulator, and the accumulator is allowed to overflow all the way up to bit 71 (destroying its sign). If the Catastrophic Overflow Trap Enable (COVTE) bit (INTCON4[8] in the interrupt controller) is set, a catastrophic overflow initiates an arithmetic error trap.

Accumulator saturation and overflow detection can only result from the execution of a DSP instruction that modifies one of the two accumulators via the 72-bit DSP ALU. Saturation and overflow detection do not take place when the accumulators are accessed via the MCU class of instructions. Furthermore, the Accumulator Status bits shown in Table 3-6 are not modified. However, the MCU Status bits (Z, N, C, OV, DC) will be modified, depending on the MCU instruction that accesses the accumulator.