Question

Write a subroutine to fill the memory location 2501H to 25FF H with Hex number 01H to FFH.

Answer 1

FILL:   LXI H, 2501H     ; HL points to starting address
        MVI A, 01H       ; A = 01H (initial data)
        MVI B, FFH       ; Counter = FFH (255 locations)

LOOP:   MOV M, A         ; Store A at memory location [HL]
        INX H            ; Point to next memory location
        INR A            ; Increment data (01H → FFH)
        DCR B            ; Decrement counter
        JNZ LOOP         ; Repeat until B = 00H

        RET              ; Return from subroutine