Instruction Set
4-116
JNS
Jump If Not Sign
JNS
What It Does
If the previous instruction clears the Sign Flag (SF), JNS stops executing the current
sequence of instructions and begins executing a new sequence of instructions; otherwise,
execution continues with the next instruction.
Syntax
Description
JNS tests the flag set by a previous instruction. If the given condition is true (SF=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
JNS
rel8
79
cb
Jump short if not sign (SF=0)
13,4
13,4
JNS
label
To jump if the result of a previous
operation cleared SF to 0, use JNS.
if (SF == 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 –
Summary of Contents for Am186 Series
Page 1: ...Am186 and Am188 Family Instruction Set Manual February 1997...
Page 10: ...Table of Contents x...
Page 18: ...Programming 1 8...
Page 40: ...Instruction Set Listing 3 14...