CHAPTER 3 CPU ARCHITECTURE
User's Manual U11919EJ3V0UM00
54
(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 except non-maskable
interrupt are disabled.
When IE = 1, the interrupt enabled (EI) status is set and interrupt request acknowledgement is controlled
with an interrupt mask flag for each interrupt source.
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 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.
www.DataSheet4U.com
Содержание UPD789022
Страница 2: ...User s Manual U11919EJ3V0UM00 2 MEMO www DataSheet4U com ...
Страница 8: ...User s Manual U11919EJ3V0UM00 8 MEMO www DataSheet4U com ...
Страница 12: ...User s Manual U11919EJ3V0UM00 12 MEMO www DataSheet4U com ...
Страница 22: ...User s Manual U11919EJ3V0UM00 22 MEMO www DataSheet4U com ...
Страница 32: ...User s Manual U11919EJ3V0UM00 32 MEMO www DataSheet4U com ...
Страница 84: ...User s Manual U11919EJ3V0UM00 84 MEMO www DataSheet4U com ...
Страница 92: ...User s Manual U11919EJ3V0UM00 92 MEMO www DataSheet4U com ...
Страница 104: ...User s Manual U11919EJ3V0UM00 104 MEMO www DataSheet4U com ...
Страница 166: ...User s Manual U11919EJ3V0UM00 166 MEMO www DataSheet4U com ...
Страница 178: ...User s Manual U11919EJ3V0UM00 178 MEMO www DataSheet4U com ...
Страница 184: ...User s Manual U11919EJ3V0UM00 184 MEMO www DataSheet4U com ...
Страница 204: ...User s Manual U11919EJ3V0UM00 204 MEMO www DataSheet4U com ...
Страница 206: ...User s Manual U11919EJ3V0UM00 206 MEMO www DataSheet4U com ...
Страница 212: ...User s Manual U11919EJ3V0UM00 212 MEMO www DataSheet4U com ...