CONTROL REGISTERS

S3C84E5/C84E9/P84E9

 

 

Bit number(s) that is/are appended to

Name of individual

 

the register name for bit addressing

bit or related bits

Register location

 

 

 

 

 

Register address

in the internal

Register ID

Register name

(hexadecimal)

register file

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

 

Bit Addressing

Register addressing mode only

 

 

 

 

 

 

 

Mode

 

 

 

 

 

 

 

 

 

 

 

 

 

 

.7

 

 

Carry Flag (C)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

Operation does not generate a carry or borrow condition

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

Operation generates carry-out or borrow into high-order bit 7

.6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Zero Flag (Z)

 

 

 

 

 

 

 

 

 

 

0Operation result is a non-zero value

0Operation result is zero

.5

Sign Flag (S)

0

Operation generates positive number (MSB = "0")

 

 

0

Operation generates negative number (MSB = "1")

 

 

R = Read-only

Description of the

 

 

W = Write-only

effect of specific

RESET value notation:

 

R/W = Read/write

bit settings

 

'-' = Not used

 

'-' = Not used

 

Bit number:

 

'x' = Undetermined value

 

 

 

 

MSB = Bit 7

Type of addressing

 

'0' = Logic zero

 

LSB = Bit 0

that must be used to

 

'1' = Logic one

 

 

address the bit

 

 

 

(1-bit, 4-bit, or 8-bit)

 

 

 

Figure 4-1. Register Description Format

4-4

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Image 73
Samsung S3C84E5 Bit Identifier Reset Value Read/Write Bit Addressing, Mode Carry Flag C, Zero Flag Z, Sign Flag S