Calculate File Descriptor for 1 sector of BATTLE.BIN

00068d40: 27bdffe8 addiu r29,r29,0xffe8
00068d44: 3c048005 lui r4,0x8005
00068d48: 2484eaf4 addiu r4,r4,0xeaf4
00068d4c: 34060001 ori r6,r0,0x0001            1 sector
00068d50: 3c058004 lui r5,0x8004
00068d54: 8ca559c8 lw r5,0x59c8(r5)            LBA 0x3e8 BATTLE.BIN
00068d58: afbf0010 sw r31,0x0010(r29)
00068d5c: 0c01a178 jal 0x000685e0              000685e0 - 0006863c
00068d60: 00003821 addu r7,r0,r0
00068d64: 8fbf0010 lw r31,0x0010(r29)
00068d68: 27bd0018 addiu r29,r29,0x0018
00068d6c: 03e00008 jr r31
00068d70: 00000000 nop