Instruction Set
4-14
ADD
Add Numbers
ADD
What It Does
ADD adds two integers or unsigned numbers.
Syntax
Description
ADD performs an integer addition of the two operands. ADD assigns the result to
sum and
sets the flags accordingly. ADD sign-extends immediate byte values to the appropriate size
before adding to a word operand.
Operation It Performs
Form
Opcode
Description
Clocks
Am186 Am188
ADD AL,
imm8
04
ib
Add immediate byte to AL
3
3
ADD AX,
imm16
05
iw
Add immediate word to AX
4
4
ADD
r/m8,imm8
80
/0 ib
Add immediate byte to r/m byte
4/16
4/16
ADD
r/m16,imm16
81
/0 iw
Add immediate word to r/m word
4/16
4/20
ADD
r/m16,imm8
83
/0 ib
Add sign-extended immediate byte to r/m word
4/16
4/20
ADD
r/m8,r8
00
/r
Add byte register to r/m byte
3/10
3/10
ADD
r/m16,r16
01
/r
Add word register to r/m word
3/10
3/14
ADD
r8,r/m8
02
/r
Add r/m byte to byte register
3/10
3/10
ADD
r16,r/m16
03
/r
Add r/m word to word register
3/10
3/14
ADD
sum,addend
if (
addend == imm8)
if (size(
sum) > 8)
/* extend sign of addend */
if (
addend < 0)
addend = 0xFF00 | addend;
else
addend = 0x00FF & addend;
/* add */
sum = sum + addend;
Содержание Am186 Series
Страница 1: ...Am186 and Am188 Family Instruction Set Manual February 1997...
Страница 10: ...Table of Contents x...
Страница 18: ...Programming 1 8...
Страница 40: ...Instruction Set Listing 3 14...