Table of Contents
How do you subtract two 16 bit numbers?
- Get the LSB in L register and MSB in H register of 16 Bit number.
- Exchange the content of HL register with DE register.
- Again Get the LSB in L register and MSB in H register of 16 Bit number.
- Subtract the content of L register from the content of E register.
What is the function of CX register in the subtraction program of two 16 bit numbers?
BX, CX are general purpose registers where BX is used for storing second number and CX is used to store borrow.
How can I add two 16-bit numbers in 8051?
As there is only one 16-bit Register in 89C51, 16-bit addition is performed by using ADDC instruction twice, i.e. adding LSD first and MSD next. DATAM1 “ 12; DATAM2 = 56.
What is the use of HLT instruction *?
In the x86 computer architecture, HLT (halt) is an assembly language instruction which halts the central processing unit (CPU) until the next external interrupt is fired. Interrupts are signals sent by hardware devices to the CPU alerting it that an event occurred to which it should react.
What happens when halt instruction is used?
halt puts the 80386 in a HALT state by stopping instruction execution. Execution is resumed by an nmi or an enabled interrupt. After a halt, if an interrupt is used to continue execution, the saved CS:EIP or CS:IP value points to the next instruction (after the halt). The halt instruction is privileged.
What is the function of HLT instruction in 8085?
In 8085 Instruction set, HLT is the mnemonic which stands for ‘Halt the microprocessor’ instruction. It is having a size of 1-Byte instruction. Using these particular instructions, as 8085 enters into the halt state, so we can put the8085 from further processing of next instructions.
What is branching instructions in 8085?
Branching instructions refer to the act of switching execution to a different instruction sequence as a result of executing a branch instruction. The three types of branching instructions are: Jump (unconditional and conditional) Return (unconditional and conditional)
Which instruction is used to fill in time delay?
One of the main usage of NOP instruction is in delay generation. The NOP instruction is taking four clock pulses to be fetching, decoding and executing. If the 8085 MPU is working on 6MHz clock frequency, then the internal clock frequency is 3MHz.
How do you create a delay?
Write up a delay subroutine with delay equal to half the time period of the square wave. Make any port pin high and call the delay subroutine. After the delay subroutine is finished, make the corresponding port pin low and call the delay subroutine gain. After the subroutine is finished , repeat the cycle again.
What is meant by time delay?
From Longman Dictionary of Contemporary English Ëˆtime deËŒlay noun [singular] a short period of time between one thing happening and another thing happening, especially in broadcasting or communications The programme will be broadcast with a time delay so that rude words can be edited out.
What is delay routine?
1. Developing Counter And T Microprocessor And I. 2. Counters ¢ Using counters programmer can specify that how many times an instruction (or set of instructions) is to be executed.
What is counter and time delay?
ïƒ¼ COUNTERS ARE USED TO KEEP TRACK OF EVENTS. ïƒ¼ TIME DELAYS ARE IMPORTANT IN SETTING UP REASONABLY ACCURATE TIMING BETWEEN TWO EVENTS. COUNTERS A Counter is designed simply by loading an appropriate number into one of the registers and using the INR (Increment by one) or the DCR (Decrement by one) instructions.
What is stack and subroutine?
The stack is a reserved area of the memory in RAM where we can store temporary information. The programmer can use the stack to store data. And the microprocessor uses the stack to execute subroutines. The 8085 has a 16-bit register known as the ‘Stack Pointer. ‘
How do I add a delay in assembly language?
One classic way to make a delay is to use nested decrement loops. Every time the inner loop counts down to 0, then the next decrements, and so on. It’s a bit tedious to adjust the timing, and interrupts will mess with the process, but it works.
How are AVR delays calculated?
DELAY CALCULATION FOR AVR Tdelay = Delay generated by the loop tmc = period of one machine cycle = 1/Fclk (note: 1 machine cycle = 1 clock cycle) = 1 / 16 MHz = 0.0625 usec Nmc = number of machine cycles in 1 loop = 3 (for brne Nmc = 2 cycles, we subtract 1 for the one cases where our guess is correct.)
What does Acall delay do?
The delay subroutine is mostly a cut and paste from the code we saw previously in the LED Blink tutorial, except that the outer loop count is initialized outside of the subroutine. When this instruction is reached, the microcontroller will jump back to the instruction immediately following the subroutine call.