dsPIC30F Family Reference Manual
DS70049C-page 2-12 © 2004 Microchip Technology Inc.
Register 2-1: SR: CPU Status Register
Upper Byte:
R-0 R-0 R/C-0 R/C-0 R-0 R/C-0 R -0 R/W-0
OA OB SA SB OAB SAB DA DC
bit 15 bit 8
Lower Byte: (SRL)
R/W-0
(2)
R/W-0
(2)
R/W-0
(2)
R-0 R/W-0 R/W-0 R/W-0 R/W-0
IPL<2:0> RA N OV Z C
bit 7 bit 0
bit 15 OA: Accumulator A Overflow Status bit
1 = Accumulator A overflowed
0 = Accumulator A has not overflowed
bit 14 OB: Accumulator B Overflow Status bit
1 = Accumulator B overflowed
0 = Accumulator B has not overflowed
bit 13 SA: Accumulator A Saturation ‘Sticky’ Status bit
1 = Accumulator A is saturated or has been saturated at some time
0 = Accumulator A is not saturated
Note: This bit may be read or cleared (not set).
bit 12 SB: Accumulator B Saturation ‘Sticky’ Status bit
1 = Accumulator B is saturated or has been saturated at some time
0 = Accumulator B is not saturated
Note: This bit may be read or cleared (not set).
bit 11 OAB: OA || OB Combined Accumulator Overflow Status bit
1 = Accumulators A or B have overflowed
0 = Neither Accumulators A or B have overflowed
bit 10 SAB: SA || SB Combined Accumulator ‘Sticky’ Status bit
1 = Accumulators A or B are saturated or have been saturated at some time in the past
0 = Neither Accumulator A or B are saturated
Note: This bit may be read or cleared (not set). Clearing this bit will clear SA and SB.
bit 9 DA: DO Loop Active bit
1 = DO loop in progress
0 = DO loop not in progress
bit 8 DC: MCU ALU Half Carry/Borrow
bit
1 = A carry-out from the 4th low order bit (for byte-sized data) or 8th low order bit (for word-sized data)
of the result occurred
0 = No carry-out from the 4th low order bit (for byte-sized data) or 8th low order bit (for word-sized data)
of the result occurred
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