This part works on the second half of the serial
uses some basic math and compares the results with something

  +140	00002ccc  3c004330	lis		 r0,0x4330
  +144	00002cd0  3c400000	lis		 r2,0x0
  +148	00002cd4  6c638000	xoris	 r3,r3,0x8000
  +152	00002cd8  90010038	stw		 r0,0x38(r1)
  +156	00002cdc  c8222ff8	lfd		 f1,0x2ff8(r2)	  4.5036E+15
  +160	00002ce0  9061003c	stw		 r3,0x3c(r1)
  +164	00002ce4  60000000	nop
  +168	00002ce8  60000000	nop
  +172	00002cec  c8010038	lfd		 f0,0x38(r1)
  +176	00002cf0  fc200828	fsub	 f1,f0,f1
  +180	00002cf4  480000e5	bl		 0x2dd8			  _sqrt
  +184	00002cf8  fc00081e	fctiwz	 f0,f1
  +188	00002cfc  d8010040	stfd	 f0,0x40(r1)
  +192	00002d00  60000000	nop
  +196	00002d04  60000000	nop
  +200	00002d08  80010044	lwz		 r0,0x44(r1)
  +204	00002d0c  7f9f0000	cmpw	 cr7,r31,r0
  +208	00002d10  409e0050	bne		 cr7,0x2d60



This part works on the first half of the serial, and is a loop

  +212	00002d14  3fc00000	lis		 r30,0x0
  +216	00002d18  3ba00000	li		 r29,0x0
  +220	00002d1c  3f800000	lis		 r28,0x0
  +224	00002d20  3bde401c	addi	 r30,r30,0x401c	  characterAtIndex:
  +228	00002d24  4800001c	b		 0x2d40
  +232	00002d28  809e0000	lwz		 r4,0x0(r30)	  characterAtIndex:
  +236	00002d2c  7fa5eb78	or		 r5,r29,r29
  +240	00002d30  7f63db78	or		 r3,r27,r27
  +244	00002d34  3bbd0001	addi	 r29,r29,0x1
  +248	00002d38  4bfeff03	bla		 0xfffeff00		  -[r3 characterAtIndex:]
  +252	00002d3c  7fe3f850	subf	 r31,r3,r31
  +256	00002d40  809c4018	lwz		 r4,0x4018(r28)	  length
  +260	00002d44  7f63db78	or		 r3,r27,r27
  +264	00002d48  4bfeff03	bla		 0xfffeff00		  -[r3 length]
  +268	00002d4c  7f9d1840	cmplw	 cr7,r29,r3
  +272	00002d50  419cffd8	blt		 cr7,0x2d28
  +276	00002d54  2f9f0000	cmpwi	 cr7,r31,0x0
  +280	00002d58  38600001	li		 r3,0x1
  +284	00002d5c  419e0008	beq		 cr7,0x2d64
  +288	00002d60  38600000	li		 r3,0x0
  +292	00002d64  38210070	addi	 r1,r1,0x70
  +296	00002d68  80010008	lwz		 r0,0x8(r1)
  +300	00002d6c  bb61ffec	lmw		 r27,0xffec(r1)
  +304	00002d70  7c0803a6	mtspr	 lr,r0
  +308	00002d74  4e800020	blr