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To reset the pending RST 7.5 instruction in the 8085, you need to execute a SIM instruction with a particular value in the accumulator.
PUSH FLAGS
MVI A,10H
SIM
POP FLAGS
Of course the PUSH and POP are optional, if you don't need to preserve the value of the accumulator.
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Justify RST instruction can be called 1 byte Call instruction?
The RST instruction is a 1 byte opcode with a 3 bit imbedded operand. There are 8 different RST instructions. Each pushes the PC on the stack, and loads the PC with the operand's value times 8. (0H, 8H, 10H, 18H, etc.)Pushing the PC on the stack and loading a new value into the PC is exactly what a CALL instruction does, so the RST instruction is a 1 byte CALL instruction. The difference between RST and CALL is that CALL is a 3 byte instruction which can go anywhere in memory in one instruction.
What is the purpose of RST instruction in microprocessor?
Special restart instruction used with interrupts
What does rst in 8085 software interrupt stand for?
RST is simply the opcode chosen to represent the Restart instruction.
What will be the contents of PC after the execution of RST 4 Instruction?
20H
Instruction that are present in 8085 and not in 8080?
RIM, SIM, RST, to name three.
What is the interrupt number in 8085 microprocessor and how to find interrupt's vector address?
The 8085 has five interrupts, INTR, RST5.5, RST6.5, RST7.5, and TRAP. It also has eight software interrupts, RST0, RST1, ..., RST7. The INTR interrupt requires a hardware response that is an opcode. Usually, the opcode is either a CALL instruction, in which case the interrupt vector can go anywhere in memory, or it is an RST instruction, in which case the vector is based on a table in low memory. In the case of RST instructions, either directly or via INTR, or the RSTx.5 interrupts, you simply multiply the interrupt number by 8 to get the vector address. The following table presents the vector addresses for all possible interrupts... RST 0 - 00H RST 1 - 08H RST 2 - 10H RST 3 - 18H RST 4 - 20H TRAP - 24H RST 5 - 28H RST5.5 - 2CH RST 6 - 30H RST 6.5 - 34H RST 7 - 38H RST 7.5 - 3CH
Mention any one byte call instruction and the address to which it is points to?
RST 2 is one example of a one byte call instruction. It points to 0010H.
Discuss the bit pattern of the accumulator for SIM instruction?
There are seven bits (one unused) in the accumulator prior to executing the SIM instruction that are of value. Numbering is 7 through 0, where 7 is the most significant... 7-Serial Out data - This sets the SOD pin 6-Enable serial data - if 0, ignore bit 7 5-Unused 4-Reset RST 7.5 flip-flop 3-Mask set enable - if 0, ignore bits 0, 1, and 2 2-Mask 7.5 - if 0, enable RST 7.5 1-Mask 6.5 - if 0, enable RST 6.5 0-Mask 5.5 - if 0, enable RST 5.5
Why rst x.1 rst x.2 rst x.3 not in 8085 why only rstx.5 is used?
Because that's how Intel designed the 8085. In addition to the 8080 type interrupt on the INTR pin, Intel chose, for the 8085, to implement four new interrupts, RST 5.5, RST 6.5, RST 7.5, and TRAP, each of which would not require the interrupting device to provide a vector. The naming convention of x.5 was simply in recognition that Intel placed the implicit vector halfway between two other RST vectors. As an example, RST 6.5 is halfway between RST 6 and RST 7. Since RST 6 and RST 5 are eight bytes away from each other, placing RST 6.5 in between would place a limit of four bytes, and four bytes is enough to place a three byte JMP instruction. The decimal and hex addresses of all of the vectors are... RST 0 - 0 - 00H RST 1 - 8 - 08H RST 2 - 16 - 10H RST 3 - 24 - 18H RST 4 - 32 - 20H TRAP - 36 - 24H RST 5 - 40 - 28H RST 5.5 - 44 - 2CH RST 6 - 48 - 30H RST 6.5 - 52 - 34H RST 7 - 56 - 38H RST 7.5 - 60 - 3CH
How many bytes are there for jump instruction in 8085?
There are 74 instructions in the 8085 microprocessor.
What is rst 5.5 in 8085?
RST 5.5 is an interrupt request pin (pin 9) on the 8085. It is sampled, along with other interrupt requests, one clock cycle before ALE on the falling edge of CLK. When enabled, and having priority, it causes an interrupt vector sequence using the RST 5.5 instruction, going to location 002CH.
What is the full form of rst?
1) Reset 2) Rest 3) Restart 4) reStructuredText 5) Retail sales tax
