$1.$ What is the difference between signed and unsigned integers?

$2.$ Express the following decimal numbers as a word length of $1$s complement:

$125$

$-43$

$-125$

$43$

$3.$ Used BCD to encode each of the following numbers in $4$ bytes. Express each answer in hex digits grouped by $2$ per byte:

$230$

$12348765$

$10$

$1715$

$4.$ Suppose you buy $32-$bit PC with $512$ MB of RAM. What is the $8-$hex digit address of the last byte of installed memory?

$5.$ Suppose you buy $64-$bit PC with $1024$ MB of RAM. What is the $16-$hex digit address of the last byte of installed memory?

$6.$ What is the difference between the EAX, EBX, ECX, and EDX registers?

$7.$ Define D$-$WORD?

$8.$ Explain what the following statements are doing?

mov eax, number$1$;

add eax, number$2$;

atod string;

dtoa sum, eax;

output resulstsLb$1,$ sum;

$9.$ What is the difference between eax and ax$?$

$10.$ How do AX$,$ AH$,$ AL map onto eax?