Samsung C8278X ユーザーズマニュアル
CONTROL REGISTERS
S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X
4-12
FLAGS
— System Flags Register
D5H
Set 1
Bit
Identifier
.7 .6 .5 .4 .3 .2 .1 .0
Reset Value
x x x x x x 0 0
Read/Write
R/W R/W R/W R/W R/W
R/W R R/W
Addressing Mode
Register addressing mode only
.7
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
.6
Zero Flag (Z)
0
Operation result is a non-zero value
1
Operation result is zero
.5
Sign Flag (S)
0
Operation generates a positive number (MSB = "0")
1
Operation generates a negative number (MSB = "1")
.4
Overflow Flag (V)
0
Operation result is
≤ +127 or ≥ –128
1
Operation result is > +127 or < –128
.3
Decimal Adjust Flag (D)
0
Add operation completed
1
Subtraction operation completed
.2
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
.1
Fast Interrupt Status Flag (FIS)
0
Interrupt return (IRET) in progress (when read)
1
Fast interrupt service routine in progress (when read)
.0
Bank Address Selection Flag (BA)
0
Bank 0 is selected
1
Bank 1 is selected