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MSM80C154S/83C154S¡ Semiconductor
Program status word register (PSW)
Accumulator (ACC) parity indicator.
This bit is "1" when the "1" bit number in the accumulator is an odd number, and
"0" when an even number.
NAME
ADDRESS
MSB LSB
76543210
BIT LOCATION FLAG FUNCTION
PSW 0D0H CY AC F0 RS1 RS0 OV F1 P
PSW.0 P
User flag which may be set to "0" or "1" as desired by the user.PSW.1 F1
RAM register bank switchPSW.3 RS0
RS1 RS0
00H - 07H
00
08H - 0FH
01
10H - 17H
10
18H - 1FH
11
PSW.4 RS1
Overflow flag which is set if the carry C6 from bit 6 of the ALU or CY is "1" as a
result of an arithmetic operation. The flag is also set to "1" if the resultant product
of executing multiplication instruction (MUL AB) is greater than 0FFH, but is reset
to "0" if the product is less than or equal to 0FFH.
PSW.2 OV
BANK
0
1
2
3
User flag which may be set to "0" or "1" as desired by the user.PSW.5 F0
Auxiliary carry flag.
This flag is set to "1" if a carry C
3
is generated from bit 3 of the ALU as a result of
executing an arithmetic operation instruction.
In all other cases, the flag is reset to "0".
PSW.6 AC
Main carry flag.
This flag is set to "1" if a carry C
7
is generated from bit 7 of the ALU as result of
executing an arithmetic operation instruction.
If a carry C
7
is not generated, the flag is reset to "0".
PSW.7 CY
RAM ADDRESS