INSTRUCTION SET DESCRIPTIONS
C-16
IDIV
Integer Divide:
IDIV
src
Performs a signed division of the
accumulator (and its extension) by the
source operand. If the source operand
is a byte, it is divided into the double-
length dividend assumed to be in
registers AL and AH; the single-length
quotient is returned in AL, and the
single-length remainder is returned in
AH. For byte integer division, the
maximum positive quotient is +127
(7FH) and the minimum negative
quotient is –127 (81H).
If the source operand is a word, it is
divided into the double-length dividend
in registers AX and DX; the single-
length quotient is returned in AX, and
the single-length remainder is returned
in DX. For word integer division, the
maximum positive quotient is +32,767
(7FFFH) and the minimum negative
quotient is –32,767 (8001H).
If the quotient is positive and exceeds
the maximum, or is negative and is
less than the minimum, the quotient
and remainder are undefined, and a
type 0 interrupt is generated. In
particular, this occurs if division by 0 is
attempted. Nonintegral quotients are
truncated (toward 0) to integers, and
the remainder has the same sign as
the dividend.
Instruction Operands:
IDIV reg
IDIV mem
When Source Operand is a Byte:
(temp)
←
(byte-src)
if
(temp) / (AX) > 0 and
(temp) / (AX) > 7FH or
(temp) / (AX) < 0 and
(temp) / (AX) < 0 – 7FH – 1
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) > 0 and
(temp) / (DX:AX) > 7FFFH or
(temp) / (DX:AX) < 0 and
(temp) / (DX:AX) < 0 – 7FFFH – 1
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 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: ......