Z8F6421AN00ZEM Zilog, Z8F6421AN00ZEM Datasheet - Page 269

• Manufacturer Part Number: Z8F6421AN00ZEM
• Description: KIT ICE Z8 ENCORE 64K 44LQFP
• Manufacturer: Zilog
• Series: Z8 Encore!®r
• Type: In-Circuit Emulator Systemr

Specifications of Z8F6421AN00ZEM

• Contents: Emulator Board, Cables, Software and Documentation
• For Use With/related Products: Z8 Encore! 44-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 269-3392

Flags Register
PS019921-0308
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
Bit
C
7
Z
S
V
Figure 57. Flags Register
D
H F2 F1
Figure 57
Bit
0
Flags Register
User Flags
Half Carry Flag
Decimal Adjust Flag
Overflow Flag
Sign Flag
Zero Flag
Carry Flag
Z8 Encore! XP
displays the Flags and their bit
Product Specification
eZ8
™
®
CPU Instruction Set
F64XX Series
255