Instruction Set
4-169
OR
Logical Inclusive OR
OR
What It Does
OR sets particular bits of a component to 1 according to a mask.
Syntax
Description
OR computes the inclusive OR of its two operands and places the result in the first operand.
Each bit of the result is 0 if both corresponding bits of the operands are 0; otherwise, each
bit is 1.
Operation It Performs
Flag Settings After Instruction
Form
Opcode
Description
Clocks
Am186 Am188
OR AL,
imm8
0C
ib
OR immediate byte with AL
3
3
OR AX,
imm16
0D
iw
OR immediate word with AX
4
4
OR
r/m8,imm8
80
/1 ib
OR immediate byte with r/m byte
4/16
4/16
OR
r/m16,imm16
81
/1 iw
OR immediate word with r/m word
4/16
4/20
OR
r/m16,imm8
83 /
1 ib
OR immediate byte with r/m word
4/16
4/20
OR
r/m8,r8
08 /
r
OR byte register with r/m byte
3/10
3/10
OR
r/m16,r16
09
/r
OR word register with r/m word
3/10
3/14
OR
r8,r/m8
0A
/r
OR r/m byte with byte register
3/10
3/10
OR
r16,r/m16
0B
/r
OR r/m word with word register
3/10
3/14
OR
component,mask
/* OR component with mask */
component = component | mask;
/* clear overflow and carry flags */
OF = CF = 0;
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
SF=1 if result is 0 or positive
SF=0 if result is negative
ZF=1 if result equal to 0
ZF=0 if result not equal to 0
PF=1 if low byte of result has even number of set bits
PF=0 otherwise
0
–
–
–
res ? res
res 0
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...