INSTRUCTION SET DESCRIPTIONS
C-10
CMP
Compare:
CMP
dest, src
Subtracts the source from the desti-
nation, which may be bytes or words,
but does not return the result. The
operands are unchanged, but the flags
are updated and can be tested by a
subsequent conditional jump
instruction. The comparison reflected
in the flags is that of the destination to
the source. If a CMP instruction is
followed by a JG (jump if greater)
instruction, for example, the jump is
taken if the destination operand is
greater than the source operand.
Instruction Operands:
CMP reg, reg
CMP reg, mem
CMP mem, reg
CMP reg, immed
CMP mem, immed
CMP accum, immed
(dest) – (src)
AF
ü
CF
ü
DF –
IF –
OF
ü
PF
ü
SF
ü
TF –
ZF
ü
CMPS
Compare String:
CMPS dest-string, src-string
Subtracts the destination byte or word
from the source byte or word. The
destination byte or word is addressed
by the destination index (DI) register
and the source byte or word is
addresses by the source index (SI)
register. CMPS updates the flags to
reflect the relationship of the
destination element to the source
element but does not alter either
operand and updates SI and DI to
point to the next string element.
Instruction Operands:
CMP dest-string, src-string
CMP (repeat) dest-string, src-string
(dest-string) – (src-string)
if
(DF) = 0
then
(SI)
←
(SI) + DELTA
(DI)
←
(DI) + DELTA
else
(SI)
←
(SI) – DELTA
(DI)
←
(DI) – DELTA
AF
ü
CF
ü
DF –
IF –
OF
ü
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...
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Страница 283: ......
Страница 284: ...11 Math Coprocessing...
Страница 285: ......
Страница 302: ...12 ONCE Mode...
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Страница 306: ...A 80C186 Instruction Set Additions and Extensions...
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Страница 318: ...B Input Synchronization...
Страница 319: ......
Страница 322: ...C Instruction Set Descriptions...
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Страница 371: ......
Страница 372: ...D Instruction Set Opcodes and Clock Cycles...
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Страница 396: ...Index...
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