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Articles on Trending Technologies
Technical articles with clear explanations and examples
Instruction type XCHG in 8085 Microprocessor
In 8085 Instruction set, there is one mnemonic XCHG, which stands for eXCHanGe. This is an instruction to exchange contents of HL register pair with DE register pair. This instruction uses implied addressing mode. As it is1-Byte instruction, so It occupies only 1-Byte in the memory. After execution of this instruction, the content between H and D registers and L and E registers will get swapped respectively. Mnemonics, Operand Opcode(in HEX) Bytes XCHG EB 1 Let us suppose, HL and DE register pairs are having ABCDH and 6789H contents respectively. After execution of ...
Read MoreHow to display current connection info in MySQL?
MySQL provides many functions that give the current connection information. For instance, to know about the current user, use the user() function. Syntax mysql> SELECT CURRENT_USER(); Here is the output that displays the name of the current user. +----------------+ | CURRENT_USER() | +----------------+ | root@% | +----------------+ 1 row in set (0.00 sec) In the above, % tells us about localhost. To check the current connection id, use the following method − mysql> SELECT CONNECTION_ID(); The following is the output that shows the current connection id. ...
Read MoreInstruction type LDAX rp in 8085 Microprocessor
In 8085 Instruction set, LDAX is a mnemonic that stands for LoaD Accumulator from memory pointed by eXtended register pair denoted as “rp” in the instruction. This instruction uses register indirect addressing for specifying the data. It occupies only 1-Byte in the memory. This rp can be either BC register pair represented by B or DE register pair represented by D.Note that LDAX H is not provided in 8085 instruction set. This is because, LDAX H is the same as MOV A, M in its function. Mnemonics, Operand Opcode(in HEX) Bytes LDAX B 0A 1 ...
Read MoreHow to get a list of MySQL views?
To get a list of MySQL views, we can use the SELECT command with LIKE operator. Let us see the syntax first. mysql> SELECT TABLE_SCHEMA, TABLE_NAME -> FROM information_schema.tables -> WHERE TABLE_TYPE LIKE 'VIEW'; The following is the output that displays the total number of views. +--------------+-----------------------------------------------+ | TABLE_SCHEMA | TABLE_NAME | +--------------+-----------------------------------------------+ | sys ...
Read MoreInstruction type STAX rp in 8085 Microprocessor
In 8085 Instruction set, STAX is a mnemonic that stands for SToreAccumulator contents in memory pointed by eXtended register denoted as “rp”.Hererp stands for register pair. This instruction uses register indirect addressing for specifying the destination. So using this instruction, the current content of Accumulator will be written to the memory location as pointed by 16-bit address as stored in the register pair. It occupies only 1-Byte in memory. Mnemonics, Operand Opcode(in HEX) Bytes STAX B 02 1 STAX D 12 1 STAX B is an example instruction of this type. It ...
Read MoreInstruction type LHLD a16 in 8085 Microprocessor
In 8085 Instruction set LHLD is a mnemonic that stands for Load HL pair using Direct addressing from memory location whose 16-bit address is denoted as a16. So the previous content of HL register pair will get updated with the new 16-bits value. As HL pair has to be updated, so data comes from two consecutive memory locations starting at the address a16 and also from next address location. This instruction uses absolute addressing mode for specifying the data in the instruction. It occupies 3-Bytes in the memory. Mnemonics, Operand Opcode(in HEX) Bytes LHLD Address 2A ...
Read MoreInstruction type SHLD a16 in 8085 Microprocessor
In 8085 Instruction set, SHLD is a mnemonic, which stands for Store HLpair using Direct addressing in memory location whose 16-bit address is denoted as a16. As HL pair has to be stored, so it has to be stored in two consecutive locations starting at the address a16. We know that H and L are 8-bit registers. So their contents will be stored in two consecutive memory locations as each memory location can hold 8-bits of data. This instruction uses absolute addressing mode for specifying the destination. It occupies 3-Bytes in the memory. Mnemonics, Operand Opcode(in HEX) Bytes ...
Read MoreHow to create boolean column in MySQL with false as default value?
To create a column with ‘false’ as the default value, we can use the concept of “default” at the time of creation of the table. Note − 0 represents false and 1 represents true. Creating a table using “default” false. mysql> create table TrueFalseTable -> ( -> Adult boolean default false -> ); Query OK, 0 rows affected (0.65 sec) Inserting records with no value, since we have set “default” above. mysql> insert into TrueFalseTable values(); Query OK, 1 row affected (0.16 sec) To display records. ...
Read MoreInstruction type ADD R in 8085 Microprocessor
In 8085 Instruction set, ADD R is a mnemonic that stands for “Add contents of R to Accumulator”. As addition is a binary operation, so it requires two operands to be operated on. So input operands will reside on Accumulator and R registers and after addition the result will be stored back on to Accumulator. In this case, “R” stands for any of the following registers or memory location M pointed by HL pair. R = A, B, C, D, E, H, L, or M It is 1-Byte instruction so occupies only 1-Byte in memory. As R can ...
Read MoreHow to use union and order by clause in MySQL?
Union is a type of operator in MySQL. We can use ORDER BY with this to filter records. Use UNION if you want to select rows one after the other from several tables or several sets of rows from a single table all as a single result set. Let us see an example. Creating first table mysql> create table UnionDemo1 -> ( -> id int -> ); Query OK, 0 rows affected (0.59 sec) Inserting records into first table. mysql> insert into UnionDemo1 values(1), (4), (10); Query OK, ...
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