$.$ A particular single$-$board computer has a video$-$out port. One of the ways

to use the video$-$out port is with the character buffer. While the character

matrix on the screen is $24\backslash$times $40$ characters, the character buffer is mapped

to $32\backslash$times $64$ nested array of uint$8$ ts$.$ If it had been written in C$,$ the

declaration might have looked like:

unsigned uint$8$ t characters$[32][64]$;

$0123963$

$0$

$1$

$.$

$.$

$.$

$2$ unused

$.$

$.$

$.$

$.$

$.$

$.$

$23$

$.$

$.$

$.$ unused

$31$

The base address for the character buffer is $0$x$40000.$

Each element of the character matrix is represented as a $1-$byte uint$8$ t$.$

By limiting the displayable characters to uppercase Latin letters, numerals, and some punctuation, and by applying some magic pixie dust, the

designers are able to encode the displayable characters using only $5$ bits.

Two bits are used for the character$$s display mode:

$00=$ white$-$on$-$black $01=$ black$-$on$-$white $1$x $=$ blinking

The remaining bit is used to indicate whether the cursor should be displayed under the character:

$0=$ do not display cursor here $1=$ display cursor here

$76540$

bit vector cursor mode character

Suppose that you want to place the letter $$W$(0$x$17$ in the $5-$bit encoding$)$ near the middle of the screen $($characters$[12][20]),$ black$-$on$-$white,

without the cursor.

$$ What is the hex value for the uint$8$ t that you$$d assign to that character?

character$[12][20]=0$x

$$ How many columns are in the nested array characters$[32][64]?$

number of columns $=$

$$ How much memory $($in bytes$)$ does each row of the nested array

character occupy?

memory per row $=$

$$ What is the base address $($in hex$)$ for row $12$ of the nested array

character?

row address $=0$x

$$ What is the memory address $($in hex$)$ for characters$[12][20]?$

address