;
;	CPE 221 Assembly Programming Asssignment #1 Solution
;	Fall 2012
;	This program sort a list of numbers using bubble sort algorithm
;      from highest to lowest and counts the number of swaps.
;

orig:		.org	1000
		
		lar r30,	End
		lar r29,	phase
		lar r26,	swap	
		lar r25,	loop
		lar r23,	loop2
		la  r6, 	size
		addi 	r6,r6,-1
		sub	r12, r12, r12

phase:		la	r10,0(r6)			;copy the size to r10
		addi 	r10,r10,-1
		lar 	r28,array
loop:		ld	r8, 0(r28)		;first number
		ld	r9, 4(r28)		;second number 
		sub 	r7,r8,r9
		brmi   r26,r7			;if 1st number greater, r7 will be +ve(do swap)
loop2:	addi	r28,r28,4			;point to next number in the list		
		addi	r10,r10,-1		;
		brpl	r25,r10		;if +ve go to next number in the phase , else go to next phase
		addi	r6,r6,-1
		brpl	r29,r6
		br	r30
swap:		la	r11,0(r8)		;r11 temp register used for swapping
		la	r8,0(r9)
		la	r9,0(r11)
		st	r8,0(r28)
		st	r9,4(r28)
		la 	r9,0(r11)
		addi	r12, r12, 1
		br 	r23

End:		st	r12, num_swaps
		stop
		.org 3000
array:		.dc	-9,7,-7,15,8,2,20,1,12,23,-99,33,22,17
size:		.equ  14
num_swaps:	.dw	1