- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄363666 > NSC800E (National Semiconductor Corporation) NSC800TM High-Performance Low-Power CMOS Microprocessor PDF資料下載
參數(shù)資料
| 型號： | NSC800E |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | NSC800TM High-Performance Low-Power CMOS Microprocessor |
| 中文描述： | NSC800TM高性能低功耗CMOS微處理器 |
| 文件頁數(shù)： | 13/76頁 |
| 文件大?。?/td> | 785K |
| 代理商： | NSC800E |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁當(dāng)前第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁
8.0 Functional Description
(Continued)
8.4.3 Carry (C)
A carry from the highest order bit of the accumulator during
an add instruction, or a borrow generated during a subtrac-
tion instruction sets the carry flag. Specific shift and rotate
instructions also affect this bit.
Two specific instructions in the NSC800 instruction reper-
toire set (SCF) or complement (CCF) the carry flag.
Other operations that affect the C flag are as follows:
#
Adds
#
Subtracts
#
Logic Operations (always resets C flag)
#
Rotate Accumulator
#
Rotate and Shifts
#
Decimal Adjust
#
Negation of Accumulator
Other operations do not affect the C flag.
8.4.4 Adds/Subtract (N)
This flag is used in conjunction with the H flag to ensure that
the proper BCD correction algorithm is used during the deci-
mal adjust instruction (DAA). The correction algorithm de-
pends on whether an add or subtract was previously done
with BCD operands.
The operations that set the N flag are:
#
Subtractions
#
Decrements (8-bit)
#
Complementing of the Accumulator
#
Block I/O
#
Block Searches
#
Negation of the Accumulator
The operations that reset the N flag are:
#
Adds
#
Increments
#
Logic Operations
#
Rotates
#
Set and Complement Carry
#
Input Register Indirect
#
Block Transfers
#
Load of the I or R Registers
#
Bit Tests
Other operations do not affect the N flag.
8.4.5 Parity/Overflow (P/V)
The Parity/Overflow flag is a dual-purpose flag that indi-
cates results of logic and arithmetic operations. In logic op-
erations, the P/V flag indicates the parity of the result; the
flag is set (high) if the result is even, reset (low) if the result
is odd. In arithmetic operations, it represents an overflow
condition when the result, interpreted as signed two’s com-
plement arithmetic, is out of range for the eight-bit accumu-
lator (i.e.
b
128 to
a
127).
The following operations affect the P/V flag according to
the parity of the result of the operation:
#
Logic Operations
#
Rotate and Shift
#
Rotate Digits
#
Decimal Adjust
#
Input Register Indirect
The following operations affect the P/V flag according to
the overflow result of the operation.
#
Adds (16 bit with carry, 8-bit with/without carry)
#
Subtracts (16 bit with carry, 8-bit with/without carry)
#
Increments and Decrements
#
Negation of Accumulator
The P/V flag has no significance immediately after the fol-
lowing operations.
#
Block I/O
#
Bit Tests
In block transfers and compares, the P/V flag indicates the
status of the BC register, always ending in the reset state
after an auto repeat of a block move. Other operations do
not affect the P/V flag.
8.4.6 Half Carry (H)
This flag indicates a BCD carry, or borrow, result from the
low-order four bits of operation. It can be used to correct the
results of a previously packed decimal add, or subtract, op-
eration by use of the Decimal Adjust Instruction (DAA).
The following operations affect the H flag:
#
Adds (8-bit)
#
Subtracts (8-bit)
#
Increments and Decrements
#
Decimal Adjust
#
Negation of Accumulator
#
Always Set by:
Logic AND
Complement Accumulator
Bit Testing
#
Always Reset By:
Logic OR’s and XOR’s
Rotates and Shifts
Set Carry
Input Register Indirect
Block Transfers
Loads of I and R Registers
The H flag has no significance immediately after the follow-
ing operations.
#
16-bit Adds with/without carry
#
16-Bit Subtracts with carry
#
Complement of the carry
#
Block I/O
#
Block Searches
Other operations do not affect the H flag.
13
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| NSC800N | NSC800TM High-Performance Low-Power CMOS Microprocessor |
| NSC800V | NSC800TM High-Performance Low-Power CMOS Microprocessor |
| NSC858 | NSC858 Universal Asynchronous Receiver/Transmitter |
| NSC858D | NSC858 Universal Asynchronous Receiver/Transmitter |
| NSC858E | NSC858 Universal Asynchronous Receiver/Transmitter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| NSC800E-1/883 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:8-Bit Microprocessor |
| NSC800E-1M | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:8-Bit Microprocessor |
| NSC800E-3/883 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:8-Bit Microprocessor |
| NSC800E-3M | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:8-Bit Microprocessor |
| NSC800E-4 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:8-Bit Microprocessor |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。