CONTROL REGISTERS
S3C80A5B
4-4
FLAGS - System Flags Register
.7
Carry Flag (C)
.6
Zero Flag (Z)
.5
Bit Identifier
Reset Value
Read/Write
Bit Addressing Mode
R = Read-only
W = Write-only
R/W = Read/write
'-' = Not used
Addressing mode or
modes you can use
to modify register
values
RESET value notation:
'-' = Not used
'x' = Undetermined value
'0' = Logic zero
'1' = Logic one
Bit number(s) that is/are appended to
the register name for bit addressing
Name of individual
bit or related bits
Register name
Register ID
Sign Flag (S)
0
Operation does not generate a carry or borrow condition
0
Operation generates carry-out or borrow into high-order bit 7
0
Operation result is a non-zero value
0
Operation result is zero
0
Operation generates positive number (MSB = "0")
0
Operation generates negative number (MSB = "1")
Description of the
effect of specific
bit settings
Set 1
Register location
in the internal
register file
D5H
Register address
(hexadecimal)
.7
.6
.5
x
x
x
R/W
R/W
R/W
Register addressing mode only
.4
.3
.2
.1
.0
x
R/W
x
R/W
x
R/W
x
R/W
0
R/W
Bit number:
MSB = Bit 7
LSB = Bit 0
Figure 4-1. Register Description Format