Calculate Tile Ceiling
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BATTLE.BIN : Calculate Tile Ceiling
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Parameters : r4 - Tile X coordinate
r5 - Tile Y coordinate
r6 - Tile Exit side slope mod
r7 - Tile Exit side height
Returns : r2 = Ceiling Height if any
r2 = 0x7f if no ceiling or invalid results
Uses Data from ScratchPad 0x1f800000
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00176164: 3c028019 lui r2,0x8019 |
00176168: 8c42f4e0 lw r2,-0x0b20(r2) |Pointer to scratch pad 0x1f800000 Pointer at 8019f4e0
0017616c: 00000000 nop |
00176170: 90420018 lbu r2,0x0018(r2) |Map Max X
00176174: 00000000 nop |
00176178: 00a20018 mult r5,r2 |
0017617c: 00805821 addu r11,r4,r0 |Tile's X Coord
00176180: 3408007f ori r8,r0,0x007f |Max Height (no ceiling)
00176184: 00005021 addu r10,r0,r0 |Initialize Elevation counter
00176188: 3c0c8019 lui r12,0x8019 |
0017618c: 258cf8cc addiu r12,r12,-0x0734 |Pointer : Tiles data ( 8019f8cc )
00176190: 00004812 mflo r9 |Y*Max X
@LOOP - 2 Times (Low elevation and High elevation)
00176194: 012b1021 addu r2,r9,r11 |This Iteration Tile ID (Low or High elevation)
00176198: 000210c0 sll r2,r2,0x03 |Tile's ID *8
0017619c: 004c2821 addu r5,r2,r12 |dynamic Tile data pointer ( 8019f8cc Table - from sent data)
001761a0: 90a20006 lbu r2,0x0006(r5) |Tile's 0x06
001761a4: 00000000 nop |
001761a8: 30420001 andi r2,r2,0x0001 |
001761ac: 14400019 bne r2,r0,0x00176214 #If Tile is Unselectable : branch to Next iteration
001761b0: 00000000 nop |
001761b4: 90a30003 lbu r3,0x0003(r5) |Load Halves + Depht
001761b8: 90a20004 lbu r2,0x0004(r5) |Load Slope Type
001761bc: 3063001f andi r3,r3,0x001f |Keep only halves
001761c0: 00c21007 srav r2,r2,r6 |
001761c4: 30420003 andi r2,r2,0x0003 |Keep Exit Side Slope type
001761c8: 00620018 mult r3,r2 |
001761cc: 90a40002 lbu r4,0x0002(r5) |Load Height
001761d0: 90a30005 lbu r3,0x0005(r5) |Load Tile's 0x05 (Thickness)
001761d4: 00042040 sll r4,r4,0x01 |Height * 2
001761d8: 3063001f andi r3,r3,0x001f |Thickness only Thickness ?
001761dc: 00031840 sll r3,r3,0x01 |Thickness * 2
001761e0: 00001012 mflo r2 |Halve * Exit Side slope mod
001761e4: 00822021 addu r4,r4,r2 |Exit Side Height
001761e8: 00832023 subu r4,r4,r3 |Potential Ceiling Height (Exit Side Height - Thickness)
001761ec: 308300ff andi r3,r4,0x00ff |Dynamic Ceiling Height
001761f0: 30e200ff andi r2,r7,0x00ff |Not Dynamic Exit Side Height
001761f4: 0043102b sltu r2,r2,r3 |
001761f8: 10400006 beq r2,r0,0x00176214 #If Exit Side height < Ceiling height False if no ceiling - keep 0x7f
001761fc: 310200ff andi r2,r8,0x00ff |0x7f
00176200: 0043102b sltu r2,r2,r3 |0x1 if 0x7f < Ceiling height
00176204: 10400002 beq r2,r0,0x00176210 #If Ceiling Height is invalid ? (> 0x7f)
00176208: 00000000 nop |
0017620c: 01002021 addu r4,r8,r0 |Preserve 0x7f
00176210: 00804021 addu r8,r4,r0 |r8 = Ceiling height
00176214: 254a0001 addiu r10,r10,0x0001 |Counter + 1
00176218: 29420002 slti r2,r10,0x0002 |
0017621c: 1440ffdd bne r2,r0,0x00176194 Λ Loop 2 times
00176220: 25290100 addiu r9,r9,0x0100 |High Elevation Offset
00176224: 03e00008 jr r31 |
00176228: 310200ff andi r2,r8,0x00ff |Returns Ceiling Height, or 0x7f
Return Locations
BATTLE.BIN 001757c0: 0017567c_-_00175954 00175868: 0017567c_-_00175954 00175ab0: Movement_routine 00175b80: Movement_routine 001772cc: 00177180_-_001773b4 00177344: 00177180_-_001773b4 001775ec: 001773b8_-_00177790 001776b4: 001773b8_-_00177790
