lab6_1.asm

.data
A: .word -2, 6, -1, 3, -2
.text
main:       
la $a0,A
li $a1,5
j mspfx
nop 
continue:
lock:       
j lock
nop
end_of_main:
#-----------------------------------------------------------------
#Procedure mspfx
# @brief find the maximum-prefix sum in a list of integers
# @param[in] a0: thebase address of thelist(A) need to be processed
# @param[in] a1: the number of elements in list(A) 
# @param[out]v0: the length of sub-listof Athat has the max sum.
# @param[out]v1: the max prefix sum
#-----------------------------------------------------------------
#Procedure mspfx
#function: find the maximum-prefix sum in a list of integers
#the base address of the list(A) is stored in $a0
#the number of elements is stored in a1
mspfx:  addi $v0,$zero,0		#initialize the length in $v0 to0
	addi $v1,$zero,0		#initialize the max sum in $v1to 0
	addi $t0,$zero,0		#initialize the index i in $t0 to 0
	addi $t1,$zero,0		#initialize the running sum in $t1 to 0
loop:   add $t2,$t0,$t0		#put 2i in $t2
	add $t2,$t2,$t2		#put 4i in $t2
	add $t3,$t2,$a0		#put 4i+A (address of A[i]) in $t3
	lw  $t4,0($t3)		#load A[i] from mem(t3) into $t4
	add $t1,$t1,$t4		#add A[i] to the running sum in $t1
	slt $t5,$v1,$t1		#set $t5 to 1 if max sum < new sum
	bne $t5,$zero,mdfy 	#if the max sum is less, modify results
	j   test			#done?
mdfy:   addi $v0,$t0,1		#new max-sum prefix has length i+1
	addi $v1,$t1,0		#new max sum is the running sum
test:   addi $t0,$t0,1		#incrementthe index i
	slt $t5,$t0,$a1		#set $t5 to 1 if i<n
	bne $t5,$zero,loop	#repeat if i<n
done:
#j continue
mspfx_end: