Differences

This shows you the differences between two versions of the page.

--- return_of_samus:data_locations:ram_map [2016/06/22 20:48] – Added loads of stuff, some structure too p.jboy
+++ return_of_samus:data_locations:ram_map [2020/04/03 20:07] – kkzero
@@ Line 4: / Line 4: @@
 === Overview ===
 <code>
--3FFF - 16KB ROM Bank (fixed - bank 0)
+-3FFF: 16KB ROM Bank (fixed - bank 0)
--7FFF - 16KB ROM Bank (swappable)
+-7FFF: 16KB ROM Bank (swappable)
--9FFF - 8KB Video RAM
+-9FFF: 8KB Video RAM
-A000-BFFF - 8KB Save RAM
+A000-BFFF: 8KB Save RAM
-C000-DFFF - 8KB Work RAM
+C000-DFFF: 8KB Work RAM
-E000-FDFF - Echo RAM (unused)
+E000-FDFF: Echo RAM (unused)
-FE00-FE9F - OAM
+FE00-FE9F: OAM
-FEA0-FEFF - Not usable
+FEA0-FEFF: Not usable
-FF00-FF7F - I/O Ports
+FF00-FF7F: I/O Ports
-FF80-FFFE - High RAM
+FF80-FFFE: High RAM
-FFFF      - Interrupt enable register
+FFFF:      Interrupt enable register
 </code>
@@ Line 21: / Line 21: @@
 -97FF: VRAM tiles
 -87AF: Samus
+-9F: Arm cannon
 B00-8EFF: Enemies
 x8C00-8E2F: Characters if room has message box (probably loaded with chozo?)
 -97FF: Background
 -9FFF: VRAM tilemap
--03FF: Background
+-9BFF: Background
--07FF: Window
+C00-9FFF: Window
-: Status bar
+C00: Status bar
-: Message
+C20: Message
 </code>
 === SRAM ===
 <code>
-A000-A03F - File 1
+A000-A03F: File 1
     + 00-07: 0123456789ABCDEF
-    + 08-0B: [$FFC0-C3]
+    + 08: Samus' Y position
-    + 0C-0F: [$FFC8-CB]
+    + 0A: Samus' X position
-    + 10-1C: [$D808-14]
+    + 0C: Screen Y position
-    + 1D: [$D045]
+    + 0E: Screen X position
-    + 1E: [$D055]
+    + 10: Enemy tiles source address (2 bytes)
-    + 1F: [$D050]
+    + 12: Background tiles source bank
-    + 20: [$D051]
+    + 13: Background tiles source address (2 bytes)
-    + 21: [$D052]
+    + 15: Metatile definitions source address (bank 8, 2 bytes)
-    + 22: [$D081]
+    + 17: Source address of data for $DC00..FF (bank 8, 2 bytes)
-    + 23: [$D082]
+    + 19: Bank for current room
-    + 24: [$D053]
+    + 1A: Samus passable block threshold
-    + 25: [$D054]
+    + 1B: Enemy passable block threshold
-    + 26: [$D02B]
+    + 1C: Projectile passable block threshold
-    + 27: [$D077]
+    + 1D: Samus' equipment
-    + 28: [$D078]
+    + 1E: Samus' beam
-    + 29: [$D089]
+    + 1F: Samus' energy tanks
-    + 2A: [$D092]
+    + 20: Samus' health
-    + 2B: [$D098]
+    + 22: Samus' max missiles
-    + 2C: [$D099]
+    + 24: Samus' missiles
-    + 2D: [$D09A]
+    + 26: Direction Samus is facing
-A040-A07F - File 2
+    + 27: Acid damage
-A080-A0BF - File 3
+    + 28: Spike damage
-A0C0      - Last used save slot
+    + 29: Real number of Metroids remaining
+    + 2A: Song for room
+    + 2B: In-game timer, minutes
+    + 2C: In-game timer, hours
+    + 2D: Number of Metroids remaining
+A040-A07F: File 2
+A080-A0BF: File 3
+A0C0:       Last used save slot
-A800-ACE2 - Written to in credits [$6:7920..7E02]
+A800-ACE2: Written to in credits [$6:7920..7E02]
-B000-B1BF - File 1 Item/Metroid data (0x40 bytes per map)
+B000-B1BF: File 1 Item/Metroid data (0x40 bytes per map)
-B200-B3BF - File 2 Item/Metroid data (verify)
+B200-B3BF: File 2 Item/Metroid data (verify)
-B400-B5BF - File 3 Item/Metroid data
+B400-B5BF: File 3 Item/Metroid data
 </code>
 === WRAM ===
 <code>
-C000-9F - OAM buffer (gets copied by the sprite DMA)
+C000-9F: OAM buffer (gets copied by the sprite DMA)
     + 0: Y position
     + 1: X position
@@ Line 80: / Line 88: @@
 : Priority (set: behind background)
-C205 - Mirror of SCY ($FF42)
+C203: Tile Y (see $22BC)
-C206 - Mirror of SCX ($FF43)
+C204: Tile X (see $22BC)
+C205: Scroll Y
+C206: Scroll X
-C3AA-AB - Pointer to LCD interrupt data
+C215: Tilemap address of ([$C204], [$C203]) (see $22BC)
-C500-FE - Offscreen enemy bytes (for current map)
+C308-37: Ch slots of 4 bytes according to $3:6E36
-    C540-C57F - Item/Metroid data bytes (for current map, gets copied to $C900 when switching maps)
+    + 3: XOR'd with 10h in $6E36 every fourth frame
-C600-C7FF - Enemy Slots (0x10 slots, 0x20 bytes each)
+C3A1: Scroll X for LCD interrupt handler type = 1
-C900-CABF - Item/Metroid data bytes (0x40 per map, gets saved to SRAM)
+C3A8: X position of Metroid Queen's head on screen
+C3A9: Y position of Metroid Queen's head on screen
+C3AA: A two-byte pointer to LCD interrupt data
-CEC0-CFFF - Music RAM
+C3D2: Background palette for LCD interrupt handler type = 1
-    CEDC - Song Enqueued (poking this causes the song to change the next frame)
+C3D3: Metroid Queen's health
-    CEDD - Song Playing (poking this does nothing)
+C3EF: Set to 1 in $3:6E36 if 0 < [Metroid Queen's health] < 32h, probably an aggression flag
+C3F1: Set to 1 in $3:6E36 if 0 < [Metroid Queen's health] < 64h, probably an aggression flag
+C407: Set to [$D069] in $2:4000
+C40F: bottom-most visible metatile row index in map * $10 (big-endian word).
+C411: top-most visible metatile row index in map * $10 (big-endian word).
+C413: right-most visible metatile column index in map * $10 (big-endian word).
+C415: left-most visible metatile column index in map * $10 (big-endian word).
+C417: Number of tile that Baby Metroid is touching.
+C418: Set to [$D058] in $2:4000
+C422: Cleared by $2EE3, set to 1 by $1FF5
+C423: Value for $D00F in $2EE3, cleared by $1FF5
+C424: Read by $2EE3, set to [$D078] by $1FF5
+C430: Used as index for pointer table at $1:5AB1
+C432: Scroll Y two frames ago (according to $3:4000)
+C433: Scroll Y one frame ago (according to $3:4000)
+C434: Scroll X two frames ago (according to $3:4000)
+C435: Scroll X one frame ago (according to $3:4000)
+C44B: Checked and set in $2:4000, previous value for $C458 in $239C
+C459: Used by $1:7A6C (when saving to SRAM), decides where in C540.. to process for $C900
+C45C: Used as index for table at $1:729C, value for $FFEA
+C500-FE: Object spawn states (map-specific)
+    C500-C53F: Non-persistent object (e.g. enemy) spawn states
+: Spawned in object table ("visible")
+: Dead/acquired
+        FF: Not spawned
+    C540-7F: Persistent object (e.g. item, Metroid) spawn states
+C600..C7FF: Enemy data. 20h byte slots according to $30BB, current address is kept in $D05E
+    + 0: Flags. If bits 0-3 clear, $30BB executes $30EA on slot. If bit 7 is set sprite is invisible (blinking).
+    + 1: Y coordinate. Value for $FFB7 in $30EA
+    + 2: X coordinate. Value for $FFB8 in $30EA
+    + 3: Metasprite number. Value for $FFB9 in $30EA
+    + 4: Priority bit ($80) for sprites. Value for $FFBF in $30EA
+    + 5: Sprite flip flags ($20 for horizontal, $40 for vertical)
+    + 6: Low nibble is blink frames remaining. Bit 4 is sprite palette flag.
+    + A: Frozen frame counter. Increments by 2 every 4 frames. 0 is not frozen, 1-$C4 is frozen, $C5-$D0 is thawing.
+    + B: Health
+    + 1D: Map object slot index
+C900-CABF: Item/Metroid data bytes (0x40 per map, gets saved to SRAM)
+CEC0-CFFF: Audio data
+    CEC0: Tone/sweep channel sound effect
+        CEC0: Tone/sweep channel sound effect to play
+: Nothing
+: Jumping
+: Hi-jumping
+: Screw attacking
+: Uncrouching / turning around / landing
+: Crouching / unmorphing
+: Morphing
+: Shooting beam
+: Shooting missile
+: Shooting ice beam
+                Ah: Shooting plasma beam
+                Bh: Shooting spazer beam
+                Ch: Picked up missile drop
+                Dh: Spider ball
+                Eh: Picked up energy drop
+                Fh: Shot missile door with beam
+h:
+h:
+h:
+h: Bomb laid
+h:
+h: Option select / missile select
+h: Shooting wave beam
+h:
+h: Samus' health changed
+h: No missile dud shot
+Ah:
+Bh: Metroid cry
+Ch: Saved
+Dh:
+Eh: Unpaused
+        CEC1: Tone/sweep channel sound effect playing
+        CEC3: Tone/sweep channel sound effect timer
-    CF10 - Mirror of NR10
+    CEC7: Tone channel sound effect
-    CF11 - Mirror of NR11
+        CEC7: Tone channel sound effect to play
-    CF12 - Mirror of NR12
+: Nothing
-    CF13 - Mirror of NR13
+: Nothing
-    CF14 - Mirror of NR14
+: Nothing
-    CF16 - Mirror of NR16
+: Metroid Queen cry
-    CF17 - Mirror of NR17
+: Baby Metroid hatched / clearing blocks
-    CF18 - Mirror of NR18
+: Baby Metroid cry
-    CF19 - Mirror of NR19
+: Metroid Queen hurt cry
-    CF1A - Mirror of NR30
+:
-    CF1B - Mirror of NR31
+        CEC8: Tone channel sound effect playing
-    CF1C - Mirror of NR32
-    CF1D - Mirror of NR33
+        CECA: Tone channel sound effect timer
-    CF1E - Mirror of NR34
-D00E - Disable buttons flag
+    CECE-CED4: Would be the wave channel sound effect, but is unused (only cleared) and CEE6 is exclusively used instead.
+    CED5: Noise channel sound effect
+        CED5: Noise channel sound effect to play
+: Nothing
+: Enemy shot
+: Enemy killed
+:
+: Shot block destroyed
+: Metroid hurt
+: Samus hurt
+: Acid damage
+: Shot missile door with missile
+: Metroid Queen cry
+                Ah: Metroid Queen hurt cry
+                Bh: Samus killed
+                Ch: Bomb detonated
+                Dh: Metroid killed
+                Eh:
+                Fh:
+h Footsteps
+h:
+h:
+h:
+h:
+h:
+h: Baby Metroid hatched / clearing blocks
+h: Baby Metroid cry
+h:
+h:
+Ah:
+        CED6: Noise channel sound effect playing
+        CED8: Noise channel sound effect timer
+    CEDC: Song to play
+: Nothing
+: Baby Metroid
+: Metroid Queen battle
+: Chozo ruins
+: Main caves
+: Sub caves 1
+: Sub caves 2
+: Sub caves 3
+: Final caves
+: Metroid hive
+            Ah: Item-get
+            Bh: Metroid Queen hallway
+            Ch: Metroid battle
+            Dh: Sub caves 4
+            Eh: Earthquake
+            Fh: Killed Metroid
+h: Nothing
+h: Title
+h: Samus fanfare
+h: Reach the gunship
+h: Chozo ruins, same as 3
+h: Main caves, no intro
+h: Sub caves 1, no intro
+h: Sub caves 2, no intro
+h: Sub caves 3, no intro
+h: Final caves, same as 8
+Ah: Metroid hive, same as 9
+Bh: Item-get, same as Ah
+Ch: Metroid Queen hallway, same as Bh
+Dh: Metroid battle, same as Ch
+Eh: Sub caves 4, no intro
+Fh: Metroid hive with intro
+h: Missile pickup
+    CEDD: Song playing
+    CEDE: Isolated sound effect to play
+: Go to $42EA
+: Go to $432B, play item-get music
+: Go to $4390 (restores some audio state)
+: Go to $4335, play missile pickup music
+: Go to $43FB
+            Eh: Go to $433F, play earthquake music
+            FFh: $CEDE = 0, $CEDF = 0, go to $42FA
+            Otherwise: Go to $42FA
+    CEDF: Isolated sound effect playing
+            If [$CEDE] = 0:
+: Go to $43C4 (set by isolated sound effect to play = 3, restores some audio state)
+: Go to $4418
+                Otherwise: Go to $42FA
+    CEE4: Current tone/sweep channel sound effect
+    CEE5: Current tone channel sound effect
+    CEE6: Low health beep / wave channel sound effect
+: Samus' health >= 50
+: Samus' health < 20
+: Samus' health < 30
+: Samus' health < 40
+: Samus' health < 50
+    CEE7: Current noise channel sound effect
+    CF00-60:
+        CF00: Music note offset. Set to [$5F30 + ([song to play] - 1) * 2] & ~1 in $48A0
+        CF01: Pointer to value for $CF34/$CF36. Set to [$5F30 + ([song to play] - 1) * 2 + 1] in $48A0
+        CF03: Working sound channel (1/2/3/4)
+        CF04: Set to 1 if [$CF38] != 0 in $48A0
+        CF05: Set to 2 if [$CF41] != 0 in $48A0
+        CF06: Set to 3 if [$CF4A] != 0 in $48A0
+        CF07: Set to 4 if [$CF53] != 0 in $48A0
+        CF08: Checked to mirror $CF0B/0C to $CF10/11 in $497A
+        CF09: Pointer to wave pattern data, 10h bytes
+        CF0B: Working sound channel sweep / enable
+        CF0C: Working sound channel sound length / wave pattern duty
+        CF0D: Working sound channel envelope / volume
+        CF0E: Working sound channel frequency / noise channel polynomial counter
+        CF0F: Working noise channel counter control
+        CF10-23: Audio channel options (which conveniently correspond with FF10-23)
+            CF10: Tone/sweep channel sweep
+            CF11: Tone/sweep channel sound length / wave pattern duty
+            CF12: Tone/sweep channel envelope
+            CF13: Tone/sweep channel frequency
+            CF15: Unused
+            CF16: Tone channel sound length / wave pattern duty
+            CF17: Tone channel envelope
+            CF18: Tone channel frequency
+            CF1A: Wave channel enable
+            CF1B: Wave channel sound length
+            CF1C: Wave channel volume
+            CF1D: Wave channel frequency
+            CF1F: Unused
+            CF20: Noise channel sound length
+            CF21: Noise channel envelope
+            CF22: Noise channel polynomial counter
+            CF23: Noise channel counter control
+        CF26: Song tone/sweep channel instruction pointer
+        CF28: Song tone channel instruction pointer
+        CF2A: Song wave channel instruction pointer
+        CF2C: Song noise channel instruction pointer
+        CF2E: A 12 frame timer
+        CF2F-37: Working song sound channel options
+            CF2F: Instruction pointer
+                F1 ee ss ll: For non-wave channels. Working sound channel envelope = ee, working sound channel sweep = ss, working sound channel sound length / wave pattern duty = ll
+                F1 pppp vv:  For the wave channel. Pointer to wave pattern data = pppp, working sound channel volume = vv
+                F2 pppp:     $CF01 = pppp
+                F3 oo:       Add oo to any played music notes (sets $CF00)
+                F4 nn:       Repeat from after this instruction nn times |: (sets $CF31/$CF33)
+                F5:          Repeat :| (decrements $CF31)
+            CF31: Repeat count
+            CF33: Repeat point
+            CF35: Sound envelope / volume
+            CF37: Sound length (according to song instruction F1h)
+        CF38-40: Song tone/sweep channel options
+            CF38: Set to [$5F30 + ([song to play] - 1) * 2 + 3] in $48A0
+            CF3F: Set to 1 in $48A0
+        CF41-49: Song tone channel options
+            CF41: Set to [$5F30 + ([song to play] - 1) * 2 + 5] in $48A0
+            CF48: Set to 1 in $48A0
+        CF4A-52: Song wave channel options
+            CF4A: Set to [$5F30 + ([song to play] - 1) * 2 + 7] in $48A0
+            CF51: Set to 1 in $48A0
+        CF53-5B: Song noise channel options
+            CF53: Set to [$5F30 + ([song to play] - 1) * 2 + 9] in $48A0
+            CF5A: Set to 1 in $48A0
+        CF5C: Set to D0h by [$CEDE] == 8 (timer), sets $CF3E = $CF47 = $CF59 = $CF5D = $CF5E = [a]
+: Song play = isolated sound effect to play = 0, disable sound channels
+h: a = 13h
+h: a = 25h
+h: a = 45h, $CF07 = 0, $CF50 = $CF5F = 60h
+            A0h: a = 65h
+        CF5D: Set to [$CF3E] by [$CEDE] == 8
+        CF5E: Set to [$CF47] by [$CEDE] == 8
+        CF5F: Set to [$CF50] by [$CEDE] == 8
+        CF60: Tone channel frequency tweak. Set to 1 if [$5F30 + ([song to play] - 1) * 2] & 1 in $48A0
+    CF61-C1: Mirror of $CF00-60?
+    CFC5: Backup of song playing during isolated sound effect
+    CFC7:
+: Go to $4801
+: Go to $4846. Set when unpausing: plays unpaused sound effect
+            Otherwise: $4819
+    CFC8: Flag to go to $4852, set to 40h by $4801
+    CFC9: Mirror of $CF10? (tone/sweep channel sweep)
+    CFE3: Mirror of $CF09?
+    CFE5: Low health beep / wave channel sound effect to play
+    CFE6: Low health beep / wave channel sound effect playing
+    CFE7: Mirror of $CFE6?
+    CFEC: Mirror of $CFED?
+    CFED: Audio channel output stereo flags
+    CFEE: Quickly guessing wave pattern timer
+D008: Metatile top-left
+D009: Metatile top-right
+D00A: Metatile bottom-left
+D00B: Metatile bottom-right
+D00C: Samus' previous Y position
+D00E: Door transition direction
+: Right
+: Left
+: Up
+: Down
+D00F: Set to [$C423] by $2EE3, set to 1 by escaping Metroid Queen / in Metroid Queen's mouth
+D010: Counter for spin-jumping
+D011: Nothing. Only cleared
+D012: Value for $D060 in $31F1
-D020 - Samus' pose
+D020: Samus' pose
 : Standing
 : Jumping
@@ Line 141: / Line 448: @@
 D: Escaped Metroid Queen
-D023 - Direction of Samus' movement
+D022: += 3 in $08FE during door transition
+D023: Direction of screen movement
 : Right
 : Left
@@ Line 147: / Line 455: @@
 : Down
-D027-28 - Samus X position
+D027: Samus X position
-D029-2A - Samus Y position
+D029: Samus Y position
-D02B - Direction Samus is facing
+D02B: Direction Samus is facing, mirrored from $D81E at save load.
 : Left
 : Right
-D02C - Samus turning animation counter
+D02C: Samus turning animation counter
-D045 - Item Bits
+D035: Screen right velocity
+D036: Screen left velocity
+D037: Screen up velocity
+D038: Screen down velocity
+D039: Set to 0 by load title screen
-D047 - Tiles update flag (see $FFB1..B6, $2BA3, $27BA)
+D03B: Samus' Y position on screen
+D03C: Samus' X position on screen, checked for <= A0h in $08FE
+D03D: Spider ball direction
+: In air
+: On bottom-left corner of ledge
+: On top-left corner of ledge
+: On left-facing wall
+: On bottom-right corner of ledge
+: On ceiling
+: Unused
+: On meet of left-facing wall and ceiling
+: On top-right corner of ledge
+: Unused
+        Ah: On floor
+        Bh: On meet of left-facing wall and floor
+        Ch: On right-facing wall
+        Dh: On meet of right-facing wall and ceiling
+        Eh: On meet of right-facing wall and floor
-D04D - Weapon selected
+D045: Samus' equipment, mirrored from $D815 at save load.
-D04E - Current ROM bank loaded
+: Bombs
+: Hi-jump
+: Screw attack
+: Space jump
+: Spring ball
+: Spider ball
+: Varia suit
+D046: Debug screen selector index
+D047: Tiles update flag (see $FFB1..B6, $2BA3, $27BA)
-D050 - Current e-tanks owned
+D04D: Weapon equipped.
-D051 - Current energy [BCD]
+: Normal
-D052 - Current e-tanks filled
+: Ice
-D053 - Current missile count, lo byte [BCD]
+: Wave
-D054 - Current missile count, hi byte [BCD]
+: Spazer
-D055 - Current beam Samus has
+: Plasma
-D056 - Samus' solidity index
+: Missile
+D04E: Bank
-D058 - Current level bank loaded
+D050: Samus' max energy tanks, mirrored from $D817 at save load.
-D059 - Death sequence timer. Used as index into offset table for dest address in $2FE1
+D051: Samus' health, mirrored from $D818 at save load.
+D052: Samus' filled energy tanks, mirrored from $D819 at save load.
+D053: Samus' missiles(upper nybble tens, lower nybble ones), mirrored from $D81C at save load.
+D054: Samus' missiles(upper nybble thousands, lower nybble hundreds), mirrored from $D81D at save load.
+D055: Samus' beam. Saved to SRAM, mirrored from $D816 at save load.
+: Normal
+: Ice
+: Wave
+: Spazer
+: Plasma
+D056: Samus passable block threshold
+D057: Room sprite priority
+: Sprites over BG
+: BG over sprites
+D058: Bank for current room
+D059: Death sequence timer. Used as index into offset table for dest address in $2FE1
-D065 - VRAM DMA bank (see $FFB1..B6, $2BA3)
+D064: Used in $239C as new OAM stack pointer, set to OAM stack pointer in $04DF
+D065: VRAM DMA bank (see $FFB1-B6, $2BA3)
+D066: Used in v-blank handler. Timer for fade in. Set to 40h by $0CA3, set to 2Fh by $239C when type = Ah, set to A0h by game mode Ah, set to FFh by reached the gunship
+D067: Used in title. Set to 01h by $0CA3 and game mode Ah
-D069 - Enemy Solidity Index
+D069: Enemy passable block threshold
-D06E - Highest OAM stack pointer
+D06E: Highest OAM stack pointer
-D077 - Damage done by acid [BCD?]
+D073: Two byte pointer, data for [$C215] before subtracting 21h; pointer to SRAM? Compared with F0h to enable $D09F, probably credits text
-D078 - Damage done by spikes [BCD?]
-D07A - Save slot option selected
+D076: Used in v-blank handler. Flag to go to $5:403D; set every few frames during credits
+D077: Acid damage. Saved to SRAM
+D078: Spike damage. Saved to SRAM
+D079: Flag to load characters. But also used in facing screen as a flag to check if buttons are pressed
+D07A: Save slot option selected
 : Start
 : Clear
+D07B: Used in title. Y position of stars?
+D07C: Used in title. X position of stars?
-D07E - Mirror of BGP ($FF47)
+D07E: BG palette
-D07F - Mirror of OBP0 ($FF48)
+D07F: Object 0 palette
-D080 - Mirror of OBP1 ($FF49)
+D080: Object 1 palette
-D081 - Max missile count, lo byte [BCD]
+D081: Samus' max missiles(upper nybble tens, lower nybble ones), mirrored from $D81A at save load.
-D082 - Max missile count, hi byte [BCD]
+D082: Samus' max missiles(upper nybble thousands, lower nybble hundreds), mirrored from $D81B at save load.
+D083: Read in $1:7A34, adjusts sprite Y position in $1:4DDF
+D084: Samus' health for display,   mirror of $D051/D818?
+D086: Samus' missiles for display, mirror of $D053/$D81C?
-D084 - Samus' health for display
+D089: Real number of Metroids remaining
-D085 - Number of non-empty energy tanks
+D08A: Projectile passable block threshold
-D086 - Samus' missiles for display
+D08B: Metroid Queen's room flag
+h: In Metroid Queen's room (set by screen transition command 8)
-D089 - Metroids remaining (real) [BDC]
+D08D: Value for $D05D in $31F1
-D08A - Weapon solidity index
+D08E: Index of screen transition command set.
+        Set to [$4300 + ([screen Y position high] * 10h + [screen X position high]) * 2] & ~800h by set up door transition
+D090: Metroid Queen eating pose
+        Sets Samus pose = escaping Metroid Queen when 7, checked for 5/20h and set to 6 in in Metroid Queen's mouth
+: Otherwise
+: Samus entering mouth
+: Mouth closing
+: Mouth closed
+: Samus escaping mouth
+: Swallowing Samus
+:
+: Samus escaping stomach
+h: Paralysed (can enter mouth)
+h:
+h: Dying
+D091: Set to 3 in $8:7EBC if killed a target number of Metroids or 1 if only Metroid Queen is remaining
+D092: Song for room
-D08E - Screen Transition index, lo byte
+D096: Metroids remaining shuffle timer
-D08F - Screen Transition index, hi byte
+D097: Index for $5:5620 jump table (first call in credits)
+D098: In-game timer, minutes
+D099: In-game timer, hours
+D09A: Number of Metroids remaining
+D09B: Fade in timer
-D092 - Song to resume (upon defeating a Metroid, reloading a save)
+D09E: Checked and cleared in $2:4000, value for $FFC9 in $0C37
+D09F: Flag to display in-game time in credits
+D0A0: Debug flag
-D096 - Metroids remaining shuffle timer
+D0A2: In-game timer, 256-frame periods (roughly 14ths of a minute)
+D0A3: Save slot
+D0A4: Show clear save slot option flag
-D098 - In-game timer, minutes
+D0A7: Metroids remaining in area
-D099 - In-game timer, hours
-D09A - Metroids remaining (HUD display) [BCD]
-D09F: Flag to display in-game time in credits
+D600-1F: OAM data for the starry background in the credits.
-D0A2 - In-game timer, 256-frame periods (roughly 14ths of a minute)
+D700-3F: Screen transition commands
-D0A3 - Save File Selected
-D0A4 - Show clear save slot option flag
-D0A7 - Metroids remaining in area
+D800-25: Save data. Data loaded from $1:4E64-89 by game mode Bh, loaded from $A008-2D + save slot * 40h by game mode Ch
+    D800: Samus' Y position
+    D802: Samus' X position
+    D804: Screen Y position
+    D806: Screen X position
+    D808: Enemy tiles source address (2 bytes)
+    D80A: Background tiles source bank
+    D80B: Background tiles source address (2 bytes)
+    D80D: Metatile definitions source address (bank 8, 2 bytes)
+    D80F: Source address of data for $DC00-FF (bank 8, 2 bytes)
+    D811: Bank for current room
+    D812: Samus passable block threshold (>= this tile index is passable, < is impassible)
+    D813: Enemy passable block threshold
+    D814: Projectile passable block threshold
+    D815: Samus' equipment at save load.
+    D816: Samus' beam at save load.
+    D817: Samus' max energy tanks at save load.
+    D818: Samus' health at save load.
+    D819: Samus' filled energy tanks at save load.
+    D81A: Samus' max missiles at save load. Upper nybble tens, lower nybble ones.
+    D81B: Samus' max missiles at save load. Upper nybble thousands, lower nybble hundreds.
+    D81C: Samus' missiles at save load. Upper nybble tens, lower nybble ones.
+    D81D: Samus' missiles at save load. Upper nybble thousands, lower nybble hundreds.
+    D81E: Direction Samus is facing at save load.
+    D81F: Acid damage
+    D820: Spike damage
+    D821: Real number of Metroids remaining
+    D822: Song for room
+    D823: In-game timer, minutes
+    D824: In-game timer, hours
+    D825: Number of Metroids remaining
-D700-D73F - Door Transition Data Buffer
+D900-FF: 10h byte slots? The first byte of which each is cleared when saving
+DA00-DBFF: Metatile definitions
+DC00-FF: Tile properties
+: Viscous. Reduces jumping and detaches spider ball on movement. Also causes morph ball sound effect glitch.
+: Jump-through block. Passable when jumping, impassable in all other states (in all directions).
+: Fall-through block. Passable when falling, impassable in all other states (in all directions).
+: Spike
+h: Acid
+h: Destructible by shot/bomb
+h: Destructible by bomb
+h: Save pillar
-D800-D825 - Savegame data buffer
+DD00-FF: Projectile RAM
+    Beams - Takes up three 16-byte rows for each shot on-screen. Spazer and Plasma take up all three immediately.
-DA00-DBFF - Metatile data buffer
+    DD00, DD10, DD20: Beam state.
-DC00-FF - Collision data buffer
+-4: On-screen, being fired. Value will match the currently-equipped beam's as stored at D055.
-DD00-FF - Projectile RAM
+        FFh: Not on-screen.
-DE00-FF - Entries to update tilemap. [word] [byte] [byte] [byte] [byte] = dest address, TL, TR, BL, BR
+    DD01, DD11, DD21: Direction of fire.
-    + 0: Dest. address
+: To the right.
+: to the left.
+: Upwards.
+: Downwards.
+    DD02, DD12, DD22: Shot Y position.
+    DD03, DD13, DD23: Shot X position.
+    DD04, DD14, DD24: Unknown, switches between 0 and 8 on a seemingly random interval between firings.
+    DD05, DD15, DD25: Displacement from position fired at, ends up differently for each direction.
+    Missiles - Shares a 16-byte row with the third beam slot.
+    DD20: Missile state.
+: On-screen, being fired.
+        FFh: Not on-screen.
+    DD21: Direction of fire.
+: To the right.
+: to the left.
+: Upwards.
+: Downwards.
+    DD22: Shot Y position.
+    DD23: Shot X position.
+    DD24: Unknown, switches between 0 and 8 on a seemingly random interval between firings.
+    DD25: Displacement from position fired at, ends up differently for each direction.
+    Bombs - Takes up three 16-byte rows for each bomb on-screen.
+    DD30, DD40, DD50: Bomb state.
+: Laid, waiting to explode.
+: Exploding.
+        FFh: No bomb on-screen.
+    DD31, DD41, DD51: Bomb timer. Starts at the value it was set at and decreases to zero.
+    DD32, DD42, DD52: Bomb Y position.
+    DD33, DD43, DD53: Bomb X position.
+DE00-FF: Metatile update entries
+    + 0: Dest. address. $0000 terminates update
     + 2: Top-left tile
     + 3: Top-right tile
     + 4: Bottom-left tile
     + 5: Bottom-right tile
-DF00-FF - Stack
+DF00-FF: Stack
 </code>
 === HRAM ===
 <code>
-FF80 - Buttons being held
+FF80: Buttons
 : A
 : B
@@ Line 244: / Line 702: @@
 : Up
 : Down
-FF81 - New buttons just pressed
+FF81: New buttons
-FF82 - V-blank handled flag
+FF82: V-blank handled flag
-FF8D - OAM offset (beginning of first unused entry)
+FF8D: OAM stack pointer
-FF97 - Frame counter
+FF97: Frame counter
-FF98 - Sprite tile number (see $5:4015)
+FF98: Sprite tile number (see $5:4015). Mirror of sprite Y position (see $30BB). Door scroll flags (see $08FE): [$4200 + [screen Y position, screen] * 16 + [screen X position, screen]]
-FF99 - Two sprite tile numbers (see $5:4000)
+FF99: Two sprite tile numbers (see $5:4000). Mirror of sprite X position (see $30BB). Door thing (see $08FE): [Samus' Y position] - [$FFC8] + 60h
-FF9B - Game mode
+FF9B: Game mode
 : Boot
 : Title screen
@@ Line 275: / Line 733: @@
 h: Credits
-FFA0-FFA9 - Sprite DMA Routine
+FFA0-A9: OAM DMA routine
+FFAA: VRAM tilemap metatile update address. $FFAA = $9800 + ([row block to update] * 32 + [column block to update]) * 2
-FFB1-B2 - VRAM DMA source address
+FFAC: Index of screen for metatile update. $FFAC = [row screen to update] * 16 + [column screen to update]
-FFB3-B4 - VRAM DMA dest address, also source offset from $CE20 when [$D08C] is set
+FFAD: Index of block for metatile update. $FFAD = [row block to update] * 16 + [column block to update]
-FFB5-B6 - VRAM DMA size
+FFAE: Number of blocks to update
-FFB7-BB - Energy tank graphics
+FFAF: Stack pointer for metatile update entries
+FFB1: VRAM DMA source address
+FFB3: VRAM DMA dest address, also source offset from $CE20 when [$D08C] is set
+FFB5: VRAM DMA size
+FFB7-BB: Energy tank graphics, other stuff too though
+FFB7: Offset for interval for [$FF98] in $30EA
+FFB8: Offset for interval for [$FF99] in $30EA
+FFB9: Table index for offset data     in $30EA
+FFBA: Start   of interval for [$FF98] in $30EA
+FFBB: End     of interval for [$FF98] in $30EA
+FFBC: Start   of interval for [$FF99] in $30EA
+FFBD: End     of interval for [$FF99] in $30EA
-FFC0 - Samus Y pos (pixels)
+FFBF: Flags to negate values in $30EA
-FFC1 - Samus Y pos (screens)
+FFC0: Samus' Y position
-FFC2 - Samus X pos (pixels)
+FFC2: Samus' X position
-FFC3 - Samus X pos (screens)
+FFC4: Sprite Y position (see $5:4015)
-FFC4 - temp sprite Y position
+FFC5: Sprite X position (see $5:4015)
-FFC5 - temp sprite X position
+FFC6: Sprite set
-FFC6 - temp sprite frame/tile (depends on the subroutine using it)
+FFC7: Sprite attributes (see $5:4015)
-FFC7 - temp sprite attributes
+FFC8: Screen Y position
-FFC8 - Camera Y position (pixels)
+FFCA: Screen X position
-FFC9 - Camera Y position (screens)
+FFCC: Row to update    (in pixels)
-FFCA - Camera X position (pixels)
+FFCE: Column to update (in pixels)
-FFCB - Camera X position (screens)
-FFE0-FFF5 - Used by active enemies (??)
+FFE0-FFF5: Used by active enemies (??)
-FFFE - Counts every other in-game frame
+FFFE: Counts every other in-game frame
 </code>

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