P00 GetTpage

#   ROUTINE: P00 GetTpage
#       Parameters:
#           r4 = VRAM Texture mode
#              0x00: 4 bit compressed
#              0x01: 8 bit compressed
#              0x02: 16 bit (uncompressed)
#           r5 = Semi Transparency rate
#              0x00: 0.5 back + 0x5 forward
#              0x01: 1 back + 1 forward
#              0x02: 1 back - 1 forward
#              0x03: 1 back + 0.25 forward
#           r6 = texture page address (x) (must be multiple of 0x040)
#           r7 = texture page address (y) (must be multiple of 0x100)
#       Returns:
#           r2 = Tpage ID
#             if (([? Accessor Result] = 1) or ([? Accessor Result] = 2))
#              0x000f: x pos of tpage
#              0x0060: y pos of tpage
#              0x0180: semi transparency mode
#              0x0600: texture mode
#             else
#              0x000f: x pos of tpage
#              0x0010: y pos of tpage (mod 2)
#              0x0060: semi transparency mode
#              0x0180: texture mode
#              0x0800: y pos of tpage (div 2)

0002398c: 27bdffd8 addiu r29,r29,-0x0028
00023990: afb00010 sw r16,0x0010(r29)
00023994: 00808021 addu r16,r4,r0
00023998: afb20018 sw r18,0x0018(r29)
0002399c: 00a09021 addu r18,r5,r0
000239a0: afb3001c sw r19,0x001c(r29)
000239a4: 00c09821 addu r19,r6,r0
000239a8: afb10014 sw r17,0x0014(r29)
000239ac: afbf0020 sw r31,0x0020(r29)
000239b0: 0c00916f jal 0x000245bc                       #   ROUTINE: ? Accessor (0x245bc)
000239b4: 00e08821 addu r17,r7,r0
000239b8: 34030001 ori r3,r0,0x0001
000239bc: 10430006 beq r2,r3,0x000239d8                 
000239c0: 32030003 andi r3,r16,0x0003                   #   Texture mode mod 4
                                                        #   if (([? Accessor Result] != 1)
000239c4: 0c00916f jal 0x000245bc                       #       ROUTINE: ? Accessor (0x245bc) (Call #2)
000239c8: 00000000 nop
000239cc: 34030002 ori r3,r0,0x0002                     
000239d0: 1443000b bne r2,r3,0x00023a00                 #       AND ([? Accessor Result (#2)] == 2))
000239d4: 32030003 andi r3,r16,0x0003                   #       (texture mode)
                                                        #   {
000239d8: 00031a40 sll r3,r3,0x09                       #       texture mode << 9
000239dc: 32420003 andi r2,r18,0x0003                   #       semi transparency
000239e0: 000211c0 sll r2,r2,0x07                       #       semi transparency << 7
000239e4: 00621825 or r3,r3,r2                          #       (texture mode << 9) | (semi transparency << 7)
000239e8: 32220300 andi r2,r17,0x0300                   #       tpage y & 0x0300 // for a multiple of 0x100, this limits it to 3 values
000239ec: 000210c3 sra r2,r2,0x03                       #       tpage y >> 3     // absolute y value << 5
000239f0: 00621825 or r3,r3,r2                          #       leftValue = (tmode << 9) | (ABEMode << 7)) | (AbsY << 5)
000239f4: 326203ff andi r2,r19,0x03ff                   #       tpage x
000239f8: 08008e8c j 0x00023a30
000239fc: 00021183 sra r2,r2,0x06                       #       rightValue = (tpage x) >> 6 // absolute x value << 0
                                                        #   } else {
00023a00: 000319c0 sll r3,r3,0x07                       #       texture mode << 7
00023a04: 32420003 andi r2,r18,0x0003                   #       semi transparency
00023a08: 00021140 sll r2,r2,0x05                       #       ABE mode << 5
00023a0c: 00621825 or r3,r3,r2                          #       (Tmode << 7) | (ABEMode << 5)
00023a10: 32220100 andi r2,r17,0x0100                   #       tpage y & 0x100   // limited to a very small VRAM size here.
00023a14: 00021103 sra r2,r2,0x04                       #       tpage y >> 4      // absy << 4
00023a18: 00621825 or r3,r3,r2                          #       (tmode << 7) | (ABEmode << 5) | (absy << 4)
00023a1c: 326203ff andi r2,r19,0x03ff                   #       tpage x   
00023a20: 00021183 sra r2,r2,0x06                       #       tpage x >> 6 // absx << 0
00023a24: 00621825 or r3,r3,r2                          #       leftValue = (tmode << 7) | (ABEmode << 5) | (absy << 4) | (absx)
00023a28: 32220200 andi r2,r17,0x0200                   #       tpage y & 0x200
00023a2c: 00021080 sll r2,r2,0x02                       #       rightValue = tpage y << 2
                                                        #   }
00023a30: 00621025 or r2,r3,r2                          #   RETURN halfword (Tpage ID)
00023a34: 8fbf0020 lw r31,0x0020(r29)
00023a38: 8fb3001c lw r19,0x001c(r29)
00023a3c: 8fb20018 lw r18,0x0018(r29)
00023a40: 8fb10014 lw r17,0x0014(r29)
00023a44: 8fb00010 lw r16,0x0010(r29)
00023a48: 27bd0028 addiu r29,r29,0x0028
00023a4c: 03e00008 jr r31
00023a50: 00000000 nop