AMD Am186 Series, Набор инструкций

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Instruction Set Overview 2-4
2.4 USING THIS MANUAL
Each instruction is detailed in Chapter 4. The following sections explain the format used
when describing each instruction.
2.4.1 Mnemonics and Names
The primary assembly-language mnemonic and its name appear at the top of the first page
for an instruction (see Figure 2-1). Some instructions have additional mnemonics that
perform the same operation. These synonyms are listed below the primary mnemonic.
Figure 2-1 Instruction Mnemonic and Name Sample
MUL Multiply Unsigned Numbers
2.4.2 Forms of the Instruction
Many instructions have more than one form. The forms for each instruction are listed in a
table just below the mnemonics (see Figure 2-2).
Figure 2-2 Instruction Forms Table Sample
Form
The Form column specifies the syntax for the different forms of an instruction. Each form
includes an instruction mnemonic and zero or more operands. Items in italics are
placeholders for operands that must be provided. A placeholder indicates the size and type
of operand that is allowed.
Form Opcode Description
Clocks
Am186 Am188
MUL r/m8 F6 /4 AX=(r/m byte)•AL 26–28/32–34 26–28/32–34
MUL r/m16 F7 /4 DX::AX=(r/m word)•AX 35–37/41–43 35–37/45–47
This operand Is a placeholder for
imm8 An immediate byte: a signed number between –128 and 127
imm16 An immediate word: a signed number between –32768 and 32767
m An operand in memory
m8 A byte string in memory pointed to by DS:SI or ES:DI
m16
A word string in memory pointed to by DS:SI or ES:DI
m16&16
A pair of words in memory
m16:16 A doubleword in memory that contains a full address (segment:offset)
moffs8 A byte in memory that contains a signed, relative offset displacement
moffs16 A word in memory that contains a signed, relative offset displacement
ptr16:16 A full address (segment:offset)
r8 A general byte register: AL, BL, CL, DL, AH, BH, CH, or DH
r16 A general word register: AX, BX, CX, DX, BP, SP, DI, or SI
r/m8 A general byte register or a byte in memory
r/m16 A general word register or a word in memory
rel8 A signed, relative offset displacement between –128 and 127
rel16 A signed, relative offset displacement between –32768 and 32767
sreg
A segment register