Decompression with updates

Reminder: *pointer = value at the location being pointed to.
Note: variable<rx> = decompiled variable name <note at which register>

pointer<r3> Decompression(arg1<r3>, const1<r4>)
//r4 always equals 807cca60 (copied from r29)
//r3 = r31(802cafe8) + some number (0x44 in this case) = 802cb02c
{
	//build stack frame (LR, r31, r30, and r29 pushed)
	//r4 is copied back to r29, this is really stupid.
	scratch<r0> = *const1<r4>
	if (scratch<r0>!=0) {
		return pointer<r3> = null
		//and unwind stack frame
	}

	arg1<r3> -> <r5>
	offsetStack<r3> = stack<r1> + 8
	offsetTOC<r4> = TOC<r2> - 0x5570
	clear(floatingPointInvalidException<crb6>)

	result<r3> = subfunction1(offsetStack<r3>, offsetTOC<r4>, arg1<r5>)

	index2<r30> = 0
	limit<r0> = *(const1<r29> + 4)
	//limit abstracted away from r0
	for( i<r31> = 0; i<r31> < limit; i<r31>++) {
		result<r3> = stack<r1> + 8
		<r4> = *(const1<r29> + 8) + index2<r30>
		result<r3> = subfunction2(result<r3>, <r4>, 0x20);
		if(result<r3> == 0) {
			break
		}
		index2<r30> += 0x28
	}

	if( i<r31> < 0 || limit <= 0) {
		<r4> = 0
	} else {
		<r4> = i<r31> * 0x28 + *(const1<r29> + 8)
	}

	if( <r4> == 0 ) {
		return pointer<r3> = null
		//and unwind stack frame
	}

	return pointer<r3> = *(const1<r29> + 0x10) + *(<r4> + 0x20)
	//and unwind stack frame
}






result<r3> subfunction1(offsetStack<r3>, offsetTOC<r4>, arg1<r5>) {
	//build stack frame
	//LR, r25-r31
	offsetStack<r3> -> <r25>
	offsetTOC<r4> -> <r26>

	if(crb6 != 0) {
		push f1-f8
	}

	<r29> = stack<r1> + 0xA8
	<r30> = stack<r1> + 8
	<r28> = 0x0200 0000
	<r31> = -1
	<r12> = 0
	<r11> = 0x8013 0000
	push offsetTOC<r4> to stack<r1> + 0xC
	<r27> = stack<r1> + 0x74
	<r0> = 0x80128FB4
	<r4> = stack<r1> + 0x68
	push offsetStack<r3> to stack<r1> + 0x8
	<r0> -> <r3> //0x80128FB4
	push arg1<r5> to Stack<r1> + 0x10
	offsetTOC<r26> -> <r5>
	push <r6> to stack<r1> + 0x14
	<r27> -> <r6>
	push <r7 - r10, r12, r25, r28-r31>
	<r3> = subfunction1_1 (r3, r4, r5)

	if( <r5> != 0) {
		<r4> = -2
		if( <r3> < -1 ) {
			<r4> = <r3>
		}
		store byte 0 @ (<r25> + <r4>)
	}
	//unwind stack register, pop <r25> - <r31>
	//return is probably on <r3>
}

result<r3> subfunction2(previousResult<r3>, <r4>, 0x20) {
	offsetStack<r3>--
	<r4>--
	<r6> = 0x21
	while(true) {
		<r6>-- //and update condition register
		if(<r6> == 0) {
			return result2<r3> = null
		}
		<r0> = byte *( --previousResult<r3>) //predecrement
		<r5> = byte *( --<r4>) //also predecrement
		if(<r0> != <r5>) {
			return result<r3> = <r5> - <r0>
		}
		if(<r0> == 0) {
			return result2<r3> = null
		}
	}
}