//
//  demo3: find max value in a linked list

        .global main, Stop, CodeEnd, DataStart, DataEnd
	.global head, max

	.text
main:
	// Use r0 for ptr

	// max=head.value
	movw	r1,#:lower16:head
	movt	r1,#:upper16:head
	ldr	r1,[r1]
	ldr	r1,[r1,#0]	// r1 = head.value

	movw    r2,#:lower16:max
        movt    r2,#:upper16:max
	str	r1,[r2]		// max = head.value

        movw    r1,#:lower16:head
        movt    r1,#:upper16:head
        ldr     r1,[r1]
	ldr	r1,[r1,#4]	// r1=head.next
	mov	r0,r1		// ptr (r0) = head.next

while:
	cmp	r0,#0		// ptr ? null
	beq	whileEnd

	ldr	r1,[r0,#0]	// r1 = ptr.value
	movw    r2,#:lower16:max
        movt    r2,#:upper16:max
	ldr	r2,[r2]
	cmp	r1,r2		// ptr.value ? max
	
	ble	ifEnd

	// max = ptr.value
        ldr     r1,[r0,#0]      // r1 = ptr.value
        movw    r2,#:lower16:max
        movt    r2,#:upper16:max
	str	r1, [r2]

ifEnd:	// ptr=ptr.next  (r0 = ptr)

	ldr     r0,[r0,#4]	// ptr=ptr.next

	b	while

whileEnd:






Stop:
CodeEnd:
    	nop

/* --------------------------------------------------
   Begin of the permanent program variables
   -------------------------------------------------- */
	.data
DataStart:
max:    .skip   4	
head:   .4byte  p0      // head contains the address of the first list elem
                        // head->[34]->[-9]->[99]->[78]->[55]

// list structure is: [int value, next]
p0: .4byte  34, p3      // p0 contains [34, p3]
p1: .4byte  99, p2      // p1 contains [99, p2]
p2: .4byte  78, p4      // p2 contains [78, p4]
p3: .4byte  -9, p1      // p3 contains [-9, p1]
p4: .4byte  55, 0       // p4 contains [55, null]
DataEnd:

	.end