Which of the following instructions is wrong? (a) ldi r20, 0x30 (b) lds r1, 0x10

Question

Which of the following instructions is wrong? (a) ldi r20, 0x30 (b) lds r1, 0x1009 (c) ldd r10, Y+20 (d) std r16, -Z Which register is used to specify the program memory address? (a) EIND register (b) Y pointer (c) X pointer (d) Z pointer If you want to copy the contents of register pair r0: r1 to r16: rl7, which of the following instructions should be used? (a) movw r1, r17 (b) movw r0, r16 (c) movw r17, r1 (d) movw r16, r0 Assume that the contents of X is 0x1000, then which of the following data memory location's contents are loaded into the register r20 after the execution of the instruction "ldd r20,X+30"? (a) location at 0x101E (b) location at 0x1015 (c) location at 0x 1000 (d) location at 0x 1030 The data stored in [0x2010] = 5, [0x2011] = 10, [0x2012] = 20, and [0x2013] = 30, Z first points to [0x2011]. What is value of r0 and r1 after execute following code: Z++ ldi r0, +Z ldi r1, Z- (a) 30, 20 (b) 30, 30 (c) 20, 20 (d) 20, 30

Explanation / Answer

1: The last instruction is wrong.STD is for Store Indirect From Register to data space using Index Z.It is used to store one byte direct with or without displacement from the register to the data space. ST Z, rXX is the syntax. Answer d) is the correct answer

2.Index register used to specify the program memory address is Z - pointer. Answer d) is the correct answer

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