What is a condition code?
condition codes in British English plural noun. a set of single bits that indicate specific conditions within a computer. The values of the condition codes are often determined by the outcome of a prior software operation and their principal use is to govern choices between alternative instruction sequences.
What is conditional code register?
Condition Code Register. Condition Code Register. The CCR contains five flag bits, which are set by the ALU to hold information about the result of an arithmetic or logical operation instruction that has just been executed. Flags in CCR and their meanings: Carry C, bit 0.
What are condition codes in assembly?
Condition codes
In ARM state, you can use a condition code to control the execution of VFP instructions. The instruction is executed conditionally, according to the status flags in the APSR, in exactly the same way as almost all other ARM instructions.
What are condition codes CC )? Explain the use of them?
Reading the Flags
| Code | Meaning (for cmp or subs ) | Flags Tested |
|---|---|---|
| cc or lo | Unsigned lower (or carry clear). | C==0 |
| mi | Negative. The mnemonic stands for “minus”. | N==1 |
| pl | Positive or zero. The mnemonic stands for “plus”. | N==0 |
| vs | Signed overflow. The mnemonic stands for “V set”. | V==1 |
What are the commonly used condition code flags?
The N, Z, C, and V bits are the condition code flags, you can set them by arithmetic and logical operations. They can also be set by MSR and LDM instructions. The ARM7TDMI processor tests these flags to determine whether to execute an instruction. All instructions can execute conditionally in ARM state.
What is a condition flag?
Forth conditionals use flags to indicate true/false values. A flag can be generated in several ways, based on testing criteria. The flag can then be displayed from the stack with the word “.”, or it can be used as input to a conditional control command.
How many Condition Codes What are they?
Definition of ‘condition codes’
There are 8 variants of the instruction selected by the condition codes that need be set for the instruction to perform the move. It also saves the frame pointer, loads integer regstier zero with the value 3, and increments integer register 31 without changing the condition codes.
What is Assembly condition codes in Java?
Advertisements. Conditional execution in assembly language is accomplished by several looping and branching instructions. These instructions can change the flow of control in a program. Conditional execution is observed in two scenarios −
Which flag Cannot be tested directly by the condition codes?
the Q flag
The state of the Q flag cannot be tested directly by the condition codes.
What are conditional code flags or status flags?
Processor status is described as condition codes, or status flags. Condition codes refer to the information about most recently executed instruction. For example, if decrementing a register produces zero value, the zero flag ZF is set by the processor.
Which of the following is not a condition flag *?
Which of the following is not a condition flag? Explanation: Trap, direction, and interrupt are the control flags. Carry, parity, auxiliary carry, zero, sign and overflow flags are the condition flags. 26.
Which are different types of condition codes used in BC instruction?
The Condition Code and Branch Instructions
- arithmetic (add, subtract)
- logical (AND, OR, XOR)
- comparisons.
- various others.
What is BC statement in assembly language?
bc (Branch Conditional) instruction.
What are the conditional branch instructions explain each with an example?
A conditional branch instruction is a branch instruction that may or may not cause a transfer of control depending on the value of stored bits in the PSR (processor status register). Each conditional branch instruction tests a different combination of Status bits for a condition.
Which flag will not affected during logical operation?
The carry flag is set to zero for these logical operations. These operations do not carry, nor do they borrow.
What is INR instruction?
In 8085 Instruction set, INR is a mnemonic that stands for ‘INcRement’ and ‘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. This instruction is used to add 1 with the contents of R.
What is meant by an opcode?
The opcode is the instruction that is executed by the CPU and the operand is the data or memory location used to execute that instruction.
What is the function of Dad D instruction?
As the 8085 internal architecture is only 8-bits, this instruction easily takes double the time needed to add two 8-bit numbers. Here, DAD is a mnemonic, which stands for Double ADd and also rp stands for any one of the following register pairs as mentioned below.
Instruction type DAD rp in 8085 Microprocessor.
| Mnemonics, Operand | Opcode(in HEX) | Bytes |
|---|---|---|
| DAD H | 29 | 1 |
What is the instruction XTHL mean?
eXchange Top of stack with HL
In 8085 Instruction set, XTHL is a mnemonic that stands for “eXchange Top of stack with HL”. This instruction exchanges the contents of the top two locations of the stack with the contents of register pair HL.
Is 3 Byte A instruction?
Three-byte instruction is the type of instruction in which the first 8 bits indicates the opcode and the next two bytes specify the 16-bit address. The low-order address is represented in second byte and the high-order address is represented in the third byte.
How is push B instruction executed?
Let us consider PUSH B as an example instruction of this category. It is a 1-Byte instruction. The result of execution of this instruction is shown below with an example.
Instruction type PUSH rp in 8085 Microprocessor.
| Mnemonics, Operand | Opcode(in HEX) | Bytes |
|---|---|---|
| PUSH B | C5 | 1 |
| PUSH D | D5 | 1 |
| PUSH H | E5 | 1 |
| PUSH PSW | F5 | 1 |
Which flag is affected by MOV instruction?
The MOV instruction never affects the flags. Whenever the destination operand equals Zero, the Zero flag is set. A flag is set when it equals 1. A flag is clear when it equals 0.
What is the instruction sphl mean *?
In 8085 Instruction set, SPHL is an instruction with the help of which Stack Pointer will get initialized with the contents of register pair HL. It is an indirect way of initializing the stack pointer.
What is push and pop instructions?
Instructions that store and retrieve an item on a stack. Push enters an item on the stack, and pop retrieves an item, moving the rest of the items in the stack up one level.
How does the pop instruction work?
The pop instruction removes the 4-byte data element from the top of the hardware-supported stack into the specified operand (i.e. register or memory location). It first moves the 4 bytes located at memory location [SP] into the specified register or memory location, and then increments SP by 4.
What is RBX register?
rbx – register b extended. rcx – register c extended. rdx – register d extended. rbp – register base pointer (start of stack) rsp – register stack pointer (current location in stack, growing downwards)