UPD78F9500MA-CAC-A Datasheet, PDF (39/342 Pages) Renesas Technology Corp – 8-Bit Single-Chip Microcontrollers

CHAPTER 3 CPU ARCHITECTURE
(a) Interrupt enable flag (IE)
This flag controls interrupt request acknowledge operations of the CPU.
When IE = 0, the interrupt disabled (DI) status is set. All interrupt requests are disabled.
When IE = 1, the interrupt enabled (EI) status is set. Interrupt request acknowledgment is controlled with
an interrupt mask flag for various interrupt sources.
This flag is reset to 0 upon DI instruction execution or interrupt acknowledgment and is set to 1 upon EI
instruction execution.
(b) Zero flag (Z)
When the operation result is zero, this flag is set to 1. It is reset to 0 in all other cases.
(c) Auxiliary carry flag (AC)
If the operation result has a carry from bit 3 or a borrow at bit 3, this flag is set to 1. It is reset to 0 in all
other cases.
(d) Carry flag (CY)
This flag stores overflow and underflow that have occurred upon add/subtract instruction execution. It
stores the shift-out value upon rotate instruction execution and functions as a bit accumulator during bit
operation instruction execution.
User’s Manual U18172EJ3V0UD
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