Critical Hit Calculation

Critical Hit Calculation:
001864f8: 27bdffe0 addiu r29,r29,0xffe0
001864fc: afbf0018 sw r31,0x0018(r29)
00186500: 34040064 ori r4,r0,0x0064		r4 = 100 (creates random number from 0-99)
00186504: 0c063bb6 jal 0x0018eed8		Random Process (returns r2 = 0 or  1)
00186508: 34050004 ori r5,r0,0x0004		r5 = 4 (critical hit chance of 4%)
0018650c: 14400012 bne r2,r0,0x00186558		Branch if Critical did not occur
00186510: 34030001 ori r3,r0,0x0001		r3 = 1
00186514: 3c028019 lui r2,0x8019
00186518: 8c422d90 lw r2,0x2d90(r2)		Load Current Action Data Pointer
0018651c: 0c063ba8 jal 0x0018eea0		Random Process (Returns 0-7FFF)
00186520: a0430001 sb r3,0x0001(r2)		Store Critical Hit Flag
00186524: 3c048019 lui r4,0x8019
00186528: 248438ce addiu r4,r4,0x38ce
0018652c: 84830000 lh r3,0x0000(r4)		Load XA
00186530: 00000000 nop
00186534: 00430018 mult r2,r3			XA * Random
00186538: 00001012 mflo r2			r2 = XA * Random
0018653c: 04410002 bgez r2,0x00186548		Branch if Random is >= 0
00186540: 00000000 nop
00186544: 24427fff addiu r2,r2,0x7fff		XA * Random + 7FFF
00186548: 000213c3 sra r2,r2,0x0f		XA * Random / 8000h
0018654c: 00621021 addu r2,r3,r2		XA + XA * Random / 8000h (XA + Rand(0..(XA - 1)))
00186550: 0c0610fb jal 0x001843ec		Knockback Calculation
00186554: a4820000 sh r2,0x0000(r4)		Store new XA
00186558: 8fbf0018 lw r31,0x0018(r29)
0018655c: 27bd0020 addiu r29,r29,0x0020
00186560: 03e00008 jr r31
00186564: 00000000 nop