AMD Am186 Series, Instruction Set

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Instruction Set 4-124
JPO Jump If Parity Odd JPO
JNP Jump If Not Parity
What It Does
If the previous instruction clears the Parity Flag (PF), JPO and JNP stop executing the
current sequence of instructions and begin executing a new sequence of instructions;
otherwise, execution continues with the next instruction.
Syntax
Description
JPO and JNP test the flag set by a previous instruction. If the given condition is true (PF=0),
a short jump is made to the location provided as the operand.
Operation It Performs
Flag Settings After Instruction
Form Opcode Description
Clocks
Am186 Am188
JPO
rel8
7B
cb
Jump short if parity odd (PF=0) 13,4 13,4
JNP rel8 7B cb Jump short if not parity (PF=0) 13,4 13,4
JPO label
To jump if the result of a previous
operation cleared PF to 0, use JPO or
its synonym, JNP. Both forms perform
the same operation.
JNP label
if (PF == 0)
{
/* extend sign of label */
if ( label < 0)
displacement = 0xFF00 | label;
else
displacement = 0x00FF &
label;
/* branch to labeled instruction */
IP = IP + displacement;
}
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Processor Status
Flags Register
reserved
OF DF IF TF SF ZF AF PF CF
? = undefined; – = unchanged
– – – – – – res – res – res –