For these programming exercises, use only those instructions that have been discussed so far in these notes:

add	divu	mflo	sll
addi	j	mult	sra
addiu	lb	multu	srl
addu	lbu	nor	sub
and	lh	or	subu
andi	lhu	ori	sw
beq	lui	sb	xor
bne	lw	sh	xori
div	mfhi

USING MIPS

Write a program that computes the sum:

1 + 2 + 3 + 4 + 5 + ... + 98 + 99 + 100 

Do this, as above, by using the j instruction to implement a non-ending loop. Before the loop, initialize a register to zero to contain the sum, initialize another register to one to be the counter, and another register to 101₁₀. Inside the loop add the counter to the sum, increment the counter, and jump to the top of the loop.

However, now, at the top of the loop put in a beq instruction that branches out of the loop when the counter equals 101₁₀. The target of the branch should be something like this:

exit: j exit # sponge for excess machine cycles sll $0,$0,0 

Now run the program by setting the value of the PC to 0x400000 (as usual) and entering 500 or so for the number of Multiple Steps (F11). Your program will not need so many steps, but that is OK. The excess steps will be used up repeatedly executing the statment labeled "exit".