Q.Divide 0EDH by 01EH

The 8051 DIV AB instruction divides the numerator in A by the denominator in B, leaving the quotient in A and the remainder in B. Dividing $0EDH\;(237)$ by $01EH\;(30)$ gives quotient 7 remainder 27. …

[!TLDR]

$0EDH = 237$, $01EH = 30$; $237 = 7\times30 + 27$, so after DIV AB the quotient is $A = 07H$ and the remainder is $B = 1BH$ (27).

This II PUC Electronics microcontroller example uses the 8051 unsigned-division instruction $DIV AB$. Before the instruction the numerator must be in the accumulator A and the denominator in register B; after it, A holds the quotient and B holds the remainder.

8051 program:

MOV A, #0EDH   ; load EDH (237) into A (numerator)
MOV B, #01EH   ; load 1EH (30) into B (denominator)
DIV AB         ; now A = quotient, B = remainder

Working out the division in decimal ($0EDH = 237$, $01EH = 30$):

$237 \div 30 = 7 \text{ remainder } 27, \quad 7\times30 = 210, \quad 237 - 210 = 27.$ …