Syntax: SUI 8-bit Where 8-bit is an immediate data operand. Byte: 2byte Addressing Mode: Immediate Addressing Working: 1. 2. 3. 4. Flag Example: SUI 11H where [A]= 22H After execution of SUI 11H [A] = 11H Program: write an ALP for 8bit subtraction of value present in Register A that is 44H with an immediate value 30H. Store result at memory location 5000H. Label Mnemonics Comments Start: SUI 30H STA 5000H Stop: HLT Output: [5000H]= 14H
Syntax: STAX Rhp Where Rhp is higher order register the pair. (HL, BC or DE) Byte: 1byte Addressing Mode: Register Indirect Addressing Working: for execution of this instruction, microprocessor will allocate first byte for opcode and the operand is register which don't need allocation. Example: STAX H where [L]= FFH [H] = 40 H [A]= 88H After execution of STAX H [40FF H]= 88 H
Instructions of 8085 can be classified on three basis: First Classification on basis of their byte length i.e. size of instruction. 1. 1-byte instructions 2. 2-byte instructions 3. 3-byte instructions Second Classification on basis of their addressing modes i.e. kinds of approaches to fetch and execute. 1. Register Addressing 2. Immediate Addressing 3. Direct Addressing 4. Register Indirect Addressing 5. Implicit Addressing There are five sets of instructions for 8085mp Programming: 1. Data Transfer group 2. Arithmetic group 3. Logical group 4. Branching group 5. Machine Control group
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