Z8F64220100ZDA Zilog, Z8F64220100ZDA Datasheet - Page 269
Manufacturer Part Number
ADAPTER ICE Z8 ENCORE 64K 64LQFP
Specifications of Z8F64220100ZDA
For Use With/related Products
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
The Flags Register contains the status information regarding the most recent arithmetic,
logical, bit manipulation or rotate and shift operation. The Flags Register contains six bits
of status information that are set or cleared by CPU operations. Four of the bits
(C, V, Z and S) can be tested for use with conditional jump instructions. Two Flags (H and
D) cannot be tested and are used for Binary-Coded Decimal (BCD) arithmetic.
The two remaining bits, User Flags (F1 and F2), are available as general-purpose status
bits. User Flags are unaffected by arithmetic operations and must be set or cleared by
instructions. The User Flags cannot be used with conditional Jumps. They are undefined at
initial power-up and are unaffected by Reset.
positions in the Flags Register.
Interrupts, the Software Trap (TRAP) instruction, and Illegal Instruction Traps all write
the value of the Flags Register to the stack. Executing an Interrupt Return (IRET) instruc-
tion restores the value saved on the stack into the Flags Register.
U = Undefined
Figure 57. Flags Register
H F2 F1
Half Carry Flag
Decimal Adjust Flag
Z8 Encore! XP
displays the Flags and their bit
CPU Instruction Set