Intel 8XC251SP, 8XC251SA, 8XC251SQ, 8XC251SB manual Program Status Word 1 Register, PSW1

PROGRAMMING

.

PSW1

7

CY AC N RS1

		Address:		S:D1H
		Reset State:		0000 0000B
				0
RS0	OV		Z	—

Bit	Bit	Function
Number	Mnemonic
7	CY	Carry Flag:
		Identical to the CY bit in the PSW register (Figure 5-2).
6	AC	Auxiliary Carry Flag:
		Identical to the AC bit in the PSW register (Figure 5-2).
5	N	Negative Flag:
		This bit is set if the result of the last logical or arithmetic operation was
		negative (i.e., bit 15 = 1). Otherwise it is cleared.
4–3	RS1:0	Register Bank Select Bits 0 and 1:
		Identical to the RS1:0 bits in the PSW register (Figure 5-2).
2	OV	Overflow Flag:
		Identical to the OV bit in the PSW register (Figure 5-2).
1	Z	Zero Flag:
		This flag is set if the result of the last logical or arithmetic operation is
		zero. Otherwise it is cleared.
0	—	Reserved:
		The value read from this bit is indeterminate. Write a “0” to this bit.

Figure 5-3. Program Status Word 1 Register

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