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CONTROL REGISTERS
Bit number(s) that is/are appended to
the register name for bit addressing
Register ID
FLAGS − − System Flags Register
Bit Identifier
RESET
RESET Value
Read/Write
Bit Addressing
Mode
.7
.6
.5
R = Read-only
W = Write-only
R/W = Read/write
'-' = Not used
Type of addressing
that must be used to
address the bit
(1-bit, 4-bit, or 8-bit)
4-4
Name of individual
bit or related bits
Register name
.7
.6
.5
x
x
x
R/W
R/W
R/W
Register addressing mode only
Carry Flag (C)
Operation does not generate a carry or borrow condition
0
0
Operation generates carry-out or borrow into high-order bit 7
Zero Flag (Z)
Operation result is a non-zero value
0
0
Operation result is zero
Sign Flag (S)
Operation generates positive number (MSB = "0")
0
Operation generates negative number (MSB = "1")
0
Figure 4-1. Register Description Format
S3C8248/C8245/P8245/C8247/C8249/P8249
Register address
(hexadecimal)
.4
.3
x
x
R/W
R/W
Description of the
effect of specific
bit settings
Register location
in the internal
register file
D5H
Set 1
.2
.1
.0
x
x
0
R/W
R/W
R/W
RESET value notation:
'-' = Not used
'x' = Undetermined value
'0' = Logic zero
'1' = Logic one
Bit number:
MSB = Bit 7
LSB = Bit 0
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