Samsung S3P80C5 User Manual page 72

S3P80C5/C80C5/C80C8
FLAGS —
System Flags Register
Bit Identifier
RESET Value RESET
Read/Write
Addressing Mode
.7
.6
.5
.4
.3
.2
.1
.0
.7 .6
x x
R/W R/W
Register addressing mode only
Carry Flag (C)
0 Operation does not generate a carry or borrow condition
1 Operation generates a carry-out or borrow into high-order bit 7
Zero Flag (Z)
0 Operation result is a non-zero value
1 Operation result is zero
Sign Flag (S)
0 Operation generates a positive number (MSB = "0")
1 Operation generates a negative number (MSB = "1")
Overflow Flag (V)
Operation result is ≤ +127 or ≥ –128
0
1 Operation result is > +127 or < –128
Decimal Adjust Flag (D)
0 Add operation completed
1 Subtraction operation completed
Half-Carry Flag (H)
0 No carry-out of bit 3 or no borrow into bit 3 by addition or subtraction
1 Addition generated carry-out of bit 3 or subtraction generated borrow into bit 3
Fast Interrupt Status Flag (FIS)
0 Interrupt return (IRET) in progress (when read)
1 Fast interrupt service routine in progress (when read)
Bank Address Selection Flag (BA)
0 Bank 0 is selected
(normal setting for S3C80C5/C80C8)
1 Invalid selection (bank 1 is not implemented)
.5 .4
x x
R/W R/W R/W
CONTROL REGISTERS
D5H
.3 .2 .1
x x 0
R/W R
Set 1
.0
0
R/W
4-9