Consider the given C-code and its corresponding assembly code, with a few operands U1-U4 being unknown. Some useful information as well as the semantics of each unique assembly instruction is annotated as inline comments in the code. The memory is byte-addressable.

Which one of the following options is a CORRECT replacement for operands in the position (U1, U2, U3, U4) in the above assembly code?

If the numerical value of a 2-byte unsigned integer on a little endian computer is 255 more than that on a big endian computer, which of the following choices represent(s) the unsigned integer on a little endian computer?

A processor has 64 registers and uses 16-bit instruction format. It has two types of instructions: I-type and R-type. Each I-type instruction contains an opcode, a register name, and a 4-bit immediate value. Each R-type instruction contains an opcode and two register names. If there are 8 distinct I-type opcodes, then the maximum number of distinct R-type opcodes is _____.

A processor has $$16$$ integer registers $$\left( {R0,\,\,R1,\,\,..\,\,,\,\,R15} \right)$$) and $$64$$ floating point registers $$(F0, F1,… , F63).$$ It uses a $$2$$-byte instruction format. There are four categories of instructions: Type-$$1,$$ Type-$$2,$$ Type-3, and Type-$$4.$$ Type-$$1$$ category consists of four instructions, each with $$3$$ integer register operands $$(3Rs)$$. Type-$$2$$ category consists of eight instructions, each with $$2$$ floating point register operands $$(2Fs).$$ Type-$$3$$ category consists of fourteen instructions, each with one integer register operand and one floating point register operand $$(1R+1F).$$ Type-$$4$$ category consists of $$N$$ instructions, each with a floating point register operand $$(1F).$$

The maximum value of $$N$$ is __________.