PCM18XK1 Microchip Technology, PCM18XK1 Datasheet - Page 83

• Manufacturer Part Number: PCM18XK1
• Description: MODULE PROC PIC18F8680,6680,8565
• Manufacturer: Microchip Technology

Specifications of PCM18XK1

• Accessory Type: Processor Module
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: ICE2000
• For Use With: ICE2000 - EMULATOR MPLAB-ICE 2000 POD
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4.13
The Status register, shown in Register 4-3, contains the
arithmetic status of the ALU. The Status register can be
the destination for any instruction as with any other reg-
ister. If the Status register is the destination for an
instruction that affects the Z, DC, C, OV or N bits, then
the write to these five bits is disabled. These bits are set
or cleared according to the device logic. Therefore, the
result of an instruction with the Status register as
destination may be different than intended.
REGISTER 4-3:
 2004 Microchip Technology Inc.
Status Register
bit 7-5
bit 4
bit 3
bit 2
bit 1
bit 0
STATUS REGISTER
bit 7
Unimplemented: Read as ‘0’
N: Negative bit
This bit is used for signed arithmetic (2’s complement). It indicates whether the result was
negative (ALU MSB = 1).
1 = Result was negative
0 = Result was positive
OV: Overflow bit
This bit is used for signed arithmetic (2’s complement). It indicates an overflow of the
7-bit magnitude which causes the sign bit (bit 7) to change state.
1 = Overflow occurred for signed arithmetic (in this arithmetic operation)
0 = No overflow occurred
Z: Zero bit
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero
DC: Digit carry/borrow bit
For ADDWF, ADDLW, SUBLW, and SUBWF instructions:
1 = A carry-out from the 4th low order bit of the result occurred
0 = No carry-out from the 4th low order bit of the result
C: Carry/borrow bit
For ADDWF, ADDLW, SUBLW, and SUBWF instructions:
1 = A carry-out from the Most Significant bit of the result occurred
0 = No carry-out from the Most Significant bit of the result occurred
Legend:
R = Readable bit
- n = Value at POR
Note:
Note:
U-0
—
For borrow, the polarity is reversed. A subtraction is executed by adding the
2’s complement of the second operand. For rotate (RRF, RLF) instructions, this bit
is loaded with either the bit 4 or bit 3 of the source register.
For borrow, the polarity is reversed. A subtraction is executed by adding the
2’s complement of the second operand. For rotate (RRF, RLF) instructions, this bit
is loaded with either the high or low-order bit of the source register.
U-0
—
PIC18F6585/8585/6680/8680
U-0
—
W = Writable bit
‘1’ = Bit is set
R/W-x
For example, CLRF STATUS will clear the upper three
bits and set the Z bit. This leaves the Status register
as 000u u1uu (where u = unchanged).
It is recommended, therefore, that only BCF, BSF,
SWAPF, MOVFF and MOVWF instructions are used to
alter the Status register because these instructions do
not affect the Z, C, DC, OV or N bits from the Status
register. For other instructions not affecting any status
bits, see Table 25-2.
N
Note:
R/W-x
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
OV
The C and DC bits operate as a borrow and
digit borrow bit respectively, in subtraction.
R/W-x
Z
x = Bit is unknown
R/W-x
DC
DS30491C-page 81
R/W-x
C
bit 0