C-11
INSTRUCTION SET DESCRIPTIONS
CWD
Convert Word to Doubleword:
CWD
Extends the sign of the word in register
AX throughout register DX. Use to
produce a double-length (doubleword)
dividend from a word prior to
performing word division.
Instruction Operands:
none
if
(AX) < 8000H
then
(DX)
←
0
else
(DX)
←
FFFFH
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
DAA
Decimal Adjust for Addition:
DAA
Corrects the result of previously
adding two valid packed decimal
operands (the destination operand
must have been register AL). Changes
the content of AL to a pair of valid
packed decimal digits.
Instruction Operands:
none
if
((AL) and 0FH) > 9 or (AF) = 1
then
(AL)
←
(AL) + 6
(AF)
←
1
if
(AL) > 9FH or (CF) = 1
then
(AL)
←
(AL) + 60H
(CF)
←
1
AF
ü
CF
ü
DF –
IF –
OF ?
PF
ü
SF
ü
TF –
ZF
ü
DAS
Decimal Adjust for Subtraction:
DAS
Corrects the result of a previous
subtraction of two valid packed
decimal operands (the destination
operand must have been specified as
register AL). Changes the content of
AL to a pair of valid packed decimal
digits.
Instruction Operands:
none
if
((AL) and 0FH) > 9 or (AF) = 1
then
(AL)
←
(AL) – 6
(AF)
←
1
if
(AL) > 9FH or (CF) = 1
then
(AL)
←
(AL) – 60H
(CF)
←
1
AF
ü
CF
ü
DF –
IF –
OF ?
PF
ü
SF
ü
TF –
ZF
ü
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 80C186XL
Страница 1: ...80C186XL 80C188XL Microprocessor User s Manual...
Страница 2: ...80C186XL 80C188XL Microprocessor User s Manual 1995...
Страница 18: ...1 Introduction...
Страница 19: ......
Страница 27: ......
Страница 28: ...2 Overview of the 80C186 Family Architecture...
Страница 29: ......
Страница 79: ......
Страница 80: ...3 Bus Interface Unit...
Страница 81: ......
Страница 127: ......
Страница 128: ...4 Peripheral Control Block...
Страница 129: ......
Страница 137: ......
Страница 138: ...5 ClockGenerationand Power Management...
Страница 139: ......
Страница 154: ...6 Chip Select Unit...
Страница 155: ......
Страница 178: ...7 Refresh Control Unit...
Страница 179: ......
Страница 193: ......
Страница 194: ...8 Interrupt Control Unit...
Страница 195: ......
Страница 227: ......
Страница 228: ...9 Timer Counter Unit...
Страница 229: ......
Страница 253: ......
Страница 254: ...10 Direct Memory Access Unit...
Страница 255: ......
Страница 283: ......
Страница 284: ...11 Math Coprocessing...
Страница 285: ......
Страница 302: ...12 ONCE Mode...
Страница 303: ......
Страница 306: ...A 80C186 Instruction Set Additions and Extensions...
Страница 307: ......
Страница 318: ...B Input Synchronization...
Страница 319: ......
Страница 322: ...C Instruction Set Descriptions...
Страница 323: ......
Страница 371: ......
Страница 372: ...D Instruction Set Opcodes and Clock Cycles...
Страница 373: ......
Страница 396: ...Index...
Страница 397: ......