Question

Microprocessor

assmebly language and c

Write a program to add 10 byte-wide values stored in SRAM starting at address 0x0150. Use register indirect addressing mode with post-increment. Store the result in SRAM location 0x0200 using direct addressing mode.

Answer 1

Algorithm:

Step 1: Point HL register pair to memory location 0150H (indirect addressing)

Step 2: Set up a decrement counter, say C from 0AH (for 10 data)

Step 3: Load Accumulator with 00H to clear content

Step 4: Move content of memory location to register B

Step 5: Add B with Accumulator (A) and store to A. (ADD command)

Step 6: Increase memory location by one (post increment)

Step 7: Decrease C counter by one

Step 8: Until C is not equal to 0 repeat program control from Step 4:

Step 9: Store content of Accumulator to memory location 0200H (direct addressing)

Step 10: Terminate the program

Code:

LXI H, 0150H ; HL register pair points at memory location 0150H

MVI C, 0A H ; Sets up a decrement counter

MVI A, 00H ; Clears Accumulator

Jump: MOV B, M ; Moves content of memory location to B

ADD B ; Adds A and B and stores result at A

INX H ; HL pair points at M+1 memory location

DCR C ; Decreases C counter by one

JNZ Jump: ; Until C is not control jumps to jump1:

STA 0200H ; Stores result at 0200H (when C=0)

HLT