Need help with this chart Suppose EBX = 1000 (in decimal) and the unsigned decim
ID: 3671938 • Letter: N
Question
Need help with this chart
Suppose EBX = 1000 (in decimal) and the unsigned decimal values of the bytes stored in memory addresses 1000 through 1003 are 255, 255, 255, and 255. What effect do the following instructions have (independently) on this area of memory? For multi-byte data, assume the least significant byte is stored in the smallest address.
5. Suppose EBX = 1000 (in decimal) and the unsigned decimal values of the bytes stored in memory addresses 1000 through 1003 are 255, 255, 255, and 255. What effect do the following instructions have (independently) on this area of memory? For multi-byte data, assume the least significant byte is stored in the smallest address. a. ADD BYTE PTR [EBX], 1 After Address 1000 1001 1002 1003 Before 255 255 255 255 b. ADD WORD PTR [EBX], 1 After Address 1000 1001 1002 1003 Before 255 255 255 255 C. ADD DWORD PTR [EBX], 1 After Address 1000 1001 1002 1003 Before 255 255 255 255Explanation / Answer
Before getting in to the above chart,
We have to know the basic notations and EBX means Embedded Board eXpandable, a computer motherboard form factor
those are:
bit = ...1 bit...
1 nibble = 4 bits = 1/2 byte
1byte = 8 bits = 2 nibbles
1WORD = 2 bytes = 4 nibbles = 16 bits
1DWORD = 2 WORDs = 4 bytes = 8 nybbles = 32 bits(Here, DWORD means Double WORD)
1QWORD = 2 DWORDs = 4 WORDS = ..... = 64 bits(Quad(means 4,in numericals or decimal number)
And now, multi-byte data means if, data contains more than one byte then it will be called as multi-byte data.
But, in general,
in calculating binary to hecta,octa,decimal(etc.,) conversions we take one byte = 8bits.that is, we consider only 8bits at max.
Sometimes abbreviated as LSB, the least significant bit is the lowest bit in a series of numbers in binary; the LSB is located at the far right of a string. For example, in the binary number: 10111001, the least significant bit is the far right 1.
the least significant bit (LSB) is the bit position in a binary integer giving the units value,
In the first chart,that is , by considering 1BYTE(as given)
the binary representation of the decimal number 255 is 11111111 and the least significant bit is 1 as said in the above detailed explanation.
Now,for 1 word = 2 bytes=2*8=16 bits
255 in binary is, with 8 bits is 11111111 and LSB is 1
255 in binary is, with 16 bits(1 word=2 bytes) is 0000000011111111 and LSB is 1.(we can add n number of zeroes before MSB,it does not affect the value)
255 in binary is, with 32bits(2 words,that is, 1 DWORD) is 0000000000000000000000011111111 and LSB is 1 .
As in the given problem, the value at all the respective given values, 255 was considered so the above said explanation and procedureis applicable to the entire chart.(tabular form,given).