$.$DATA

VAL$1$ DW $1\backslash$Alpha $30\backslash$Eta

VAL$2$ DW $1980$H

VAL$3$ DW $20$B$5$H

REST DW $2$ DUP $(?)$

$.$CODE

MAIN PROC FAR

MOV AX$,$ @DATA

MOV DS$,$ AX

PUSH VAL$3$

PUSH VAL$2$

PUSH VAL$1$

CALL SUBR$1$

MOV RESL, AX

MOV RESL $+2,$ BX

MOV AH$,4$CH

INT $21$H

MAIN ENDP

END MAIN

SUBR$1$ PROC FAR

SUB BX$,$ BX

PUSH BP

MOV BP$,$ SP

MOV AX$,[$BP$+6]$

MOV CX$,[$ BP $+8]$

MOV DX$,[$BP $+10]$

ADD AX$,$CX

ADC BX$,00$

ADD AX$,$ DX

ADC BX$,00$

POP BP

RET $6$

SUBR$1$ ENDP

END

Assume SP $=169$BH before the "PUSH VAL$3"$ instruction in the main procedure. After the main procedure is executed, find the following:

RESI $=$

SP$=$

b$.$ User wants to add $256$k EPROMs and $256$k SRAMs to a PC using the $74138$s to decode the $64$k x$8$ memory blocks $($EPROMs and SRAMs$)$ controlled by Ys$.$ Addresses available start $50000$H and another D$0000.$

$1.$ How many memory block required from EPROMs and SRAMs?

$2.$ Determine the typical range address of added EPROMs and SRAMs?

$3.$ Determine the range of each memory block controlled by Ys$?$

$4.$ Design and draw the memory decoding using $74138$ circuitries in which the memory block controlled by Ys$?$