C-13
INSTRUCTION SET DESCRIPTIONS
DIV
Divide:
DIV
src
Performs an unsigned division of the
accumulator (and its extension) by the
source operand.
If the source operand is a byte, it is
divided into the two-byte dividend
assumed to be in registers AL and AH.
The byte quotient is returned in AL,
and the byte remainder is returned in
AH.
If the source operand is a word, it is
divided into the two-word dividend in
registers AX and DX. The word
quotient is returned in AX, and the
word remainder is returned in DX.
If the quotient exceeds the capacity of
its destination register (FFH for byte
source, FFFFH for word source), as
when division by zero is attempted, a
type 0 interrupt is generated, and the
quotient and remainder are undefined.
Nonintegral quotients are truncated to
integers.
Instruction Operands:
DIV reg
DIV mem
When Source Operand is a Byte:
(temp)
←
(byte-src)
if
(temp) / (AX) > FFH
then (type 0 interrupt is generated)
(SP)
←
(SP) – 2
((SP) + 1:(SP))
←
FLAGS
(IF)
←
0
(TF)
←
0
(SP)
←
(SP) – 2
((SP) + 1:(SP))
←
(CS)
(CS)
←
(2)
(SP)
←
(SP) – 2
((SP) + 1:(SP))
←
(IP)
(IP)
←
(0)
else
(AL)
←
(temp) / (AX)
(AH)
←
(temp) % (AX)
When Source Operand is a Word:
(temp)
←
(word-src)
if
(temp) / (DX:AX) > FFFFH
then (type 0 interrupt is generated)
(SP)
←
(SP) – 2
((SP) + 1:(SP))
←
FLAGS
(IF)
←
0
(TF)
←
0
(SP)
←
(SP) – 2
((SP) + 1:(SP))
←
(CS)
(CS)
←
(2)
(SP)
←
(SP) – 2
((SP) + 1:(SP))
←
(IP)
(IP)
←
(0)
else
(AX)
←
(temp) / (DX:AX)
(DX)
←
(temp) % (DX:AX)
AF ?
CF ?
DF –
IF –
OF ?
PF ?
SF ?
TF –
ZF ?
Table C-4. Instruction Set (Continued)
Name
Description
Operation
Flags
Affected
NOTE: The three symbols used in the Flags Affected column are defined as follows:
– the contents of the flag remain unchanged after the instruction is executed
? the contents of the flag is undefined after the instruction is executed
ü
the flag is updated after the instruction is executed
Содержание 80C186EA
Страница 1: ...80C186EA 80C188EA Microprocessor User s Manual...
Страница 2: ...80C186EA 80C188EA Microprocessor User s Manual 1995...
Страница 19: ......
Страница 20: ...1 Introduction...
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Страница 28: ...2 Overview of the 80C186 Family Architecture...
Страница 29: ......
Страница 79: ......
Страница 80: ...3 Bus Interface Unit...
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Страница 130: ...4 Peripheral Control Block...
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Страница 140: ...5 ClockGenerationand Power Management...
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Страница 166: ...6 Chip Select Unit...
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Страница 190: ...7 Refresh Control Unit...
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Страница 205: ......
Страница 206: ...8 Interrupt Control Unit...
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Страница 239: ...INTERRUPT CONTROL UNIT 8 32...
Страница 240: ...9 Timer Counter Unit...
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Страница 266: ...10 Direct Memory Access Unit...
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Страница 295: ...DIRECT MEMORY ACCESS UNIT 10 28...
Страница 296: ...11 Math Coprocessing...
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Страница 314: ...12 ONCE Mode...
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Страница 318: ...A 80C186 Instruction Set Additions and Extensions...
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Страница 330: ...B Input Synchronization...
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Страница 334: ...C Instruction Set Descriptions...
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Страница 383: ...INSTRUCTION SET DESCRIPTIONS C 48...
Страница 384: ...D Instruction Set Opcodes and Clock Cycles...
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Страница 408: ...Index...
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