Difference between revisions of "SCUMM/V5 opcodes"

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SCUMM/V5 opcodes (view source)

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=SCUMM V5 opcodes=
The following conventions are used in the encoding descriptions.


{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Term||Description
|-
|opcode||The instruction's opcode, with the appropriate bits set according to the parameters.
|-
|aux||An aux opcode that stores parameter bits and no other information.
|-
|result||A result pointer. (A standard word pointer, always a LE word.)
|-
|sub-opcode||An aux opcode that indicates a specific function to perform (e.g. the "wait" instruction has sub-opcodes to "wait for message", "wait for actor" etc), as well as storing parameter bits if necessary
|-
|var||A var pointer. Same as above, but is not written to. Because this is always a var, the opcode is not affected like with normal parameter/pointers.
|-
|value[8]||An 8-bit constant (a byte).
|-
|value[16]||A 16-bit constant (a word LE).
|-
|value[p8]||An 8-bit parameter. This may be encoded as a word LE if it's a pointer, or a byte if it's a constant.
|-
|value[p16]||A 16-bit parameter. This is always encoded as a word LE, and may be a pointer or constant.
|-
|value[v16]||A variable number of word LE parameters. These are encoded as a sequence of aux[8] param[p16]; param; aux contains the parameter bit to describe param. A byte of $FF terminates the sequence. (actually always shown as "value[v16]...")
|-
|value[o]||The offset word for parameter value. This is only encoded if needed, but always at the position indicated. If not specified, the offset word occurs immediately after the parameter.
|-
|value[c]||An ASCII character. Because some instructions use null-terminated strings and some use $FF, the exact format of a string is described in the instruction. Almost always appears as "value[c]..."
|-
|term...||One or more terms.
|}
Of course, due to the non-orthogonality of the opcodes, there are lots of exceptions.
==actorFollowCamera ($52)==
===Encoding===
opcode actor[p8]
===Operation===
Sets the camera to follow the given actor?
==actorFromPos ($15)==
===Encoding===
opcode result x[p16] y[p16]
===Operation===
Returns the actor located at the given co-ordinates.
==actorOps ($13)==
parameters depend on auxiliary opcode; terminated by $FF
===Encoding===
opcode actor[p8] sub-opcode... $FF
sub-opcodes:
$00 arg1[p8]
$01 costume[p8]
$02 xspeed[p8] yspeed[p8]
$03 sound[p8]
$04 walkframe[p8]
$05 starttalk[p8] endtalk[p8]
$06 standframe[p8]
$07 arg1[p8] arg2[p8] arg3[p8]
$08
$09 elevation[p16]
$0A
$0B index[p8] value[p8]
$0C colour[p8]
$0D name[c]... $00
$0E initframe[p8]
$10 width[p8]
$11 xscale[p8] yscale[p8]
$12
$13 zplane[p8]
$14
$15 animspeed[p8]
$16 mode[p8]
$17 shadow[p8]
===Operation===
Miscellaneous actions on actors.
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$00||dummy||A dummy case, does nothing (in ScummVM).
|-
|$01||SO_COSTUME||Sets the actor's costume.
|-
|$02||SO_STEP_DIST||Sets the actor's walking speed for x and y.
|-
|$03||SO_SOUND||Associates a sound with the actor (footsteps?)
|-
|$04||SO_WALK_ANIMATION||Sets the current frame of the walking animation.
|-
|$05||SO_TALK_ANIMATION||Sets the start and stop frames of the talking animation.
|-
|$06||SO_STAND_ANIMATION||Sets the current frame of the standing animation.
|-
|$07||SO_ANIMATION||Unknown; seems to be unused in ScummVM.
|-
|$08||SO_DEFAULT||Initializes actor.
|-
|$09||SO_ELEVATION||Sets the actor's elevation to the given value.
|-
|$0A||SO_ANIMATION_DEFAULT||Initializes the actor's animation frames.<br>Init frame = 1<br>Walk frame = 2<br>Stand frame = 3<br>Talk start frame = 4<br>Talk stop frame = 5
|-
|$0B||SO_PALETTE||Sets the colour at the given index to a new value (another entry in the colour lookup table/CLUT). Index must be between 0 and 31 (the number of colours in a costume).
|-
|$0C||SO_TALK_COLOR||Sets the actor's talk colour.
|-
|$0D||SO_ACTOR_NAME||Sets the actor's name to the given null-terminated string.
|-
|$0E||SO_INIT_ANIMATION||Sets the current frame of the initial animation.
|-
|$10||SO_ACTOR_WIDTH||Sets the actor's width.
|-
|$11||SO_ACTOR_SCALE||Sets the actor's X and Y scales.
|-
|$12||SO_NEVER_ZCLIP||Turns off all Z-clipping for the actor.
|-
|$13||SO_ALWAYS_ZCLIP||Forces the actor's Z-clipping for the given Z-plane?
|-
|$14||SO_IGNORE_BOXES||Ignores boxes, turns off Z-clipping, and puts actor somewhere if the actor is in the current room?
|-
|$15||SO_FOLLOW_BOXES||Follows boxes, turns off Z-clipping, and puts actor somewhere if the actor is in the current room?
|-
|$16||SO_ANIMATION_SPEED||Sets the animatino speed
|-
|$17||SO_SHADOW||Sets the shadow mode.
|}
===Variants===
In SCUMM V4, sub-opcode $11 (SO_ACTOR_SCALE) only takes one parameter, so X and Y scaling is done at a 1:1 ratio.
==actorSetClass ($5D)==
===Encoding===
opcode object[p16] classes[v16]...
===Operation===
Makes object inherit from all of the given classes. A class of "0" will clear all of the object's existing class data.
==add ($5A)==
===Encoding===
opcode result value[p16]
===Operation===
result := result + value
The variable pointed to by result is read, value is added to it, and the result written back.
==and ($17)==
one parameter, uses result
===Encoding===
opcode result value[p16]
===Operation===
result := result and value
The variable pointed to by result is read, logically ANDed with value, and the result written back.
==animateActor ($11)==
===Encoding===
opcode actor[p8] anim[p8]
===Operation===
Starts the given animation for the given actor.
==breakHere ($80)==
no parameters
===Encoding===
opcode
===Operation===
Deschedules the currently running thread. Execution continues at the next instruction when the thread's next timeslot comes around.
==chainScript ($42)==
one parameter plus varargs
===Encoding===
opcode script[p8] args[v16]...
===Operation===
Replaces the currently running script with another one. The current script is terminated immediately and the new script (determined by the given script ID), is executed in the same thread. The new script has its local variables initialised to the list args. Uninitialised variables have undefined values.
==cursorCommand ($2C)==
parameters depend on auxiliary opcode
===Encoding===
opcode sub-opcode
sub-opcode can be any of the following:
$01
... $01 through $08 take the same arguments ...
$08
$0A cursornum[p8] charletter[p8]
$0B index[p8] x[p8] y[p8]
$0C cursor[p8]
$0D charset[p8]
$0E colours[v16]...
===Operation===
Miscellaneous actions on cursors & charsets.
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||SO_CURSOR_ON||Turns the cursor on.
|-
|$02||SO_CURSOR_OFF||Turns the cursor off.
|-
|$03||SO_USERPUT_ON||Enables user input.
|-
|$04||SO_USERPUT_OFF||Disables user input.
|-
|$05||SO_CURSOR_SOFT_ON||Increments the cursor's state?
|-
|$06||SO_CURSOR_SOFT_OFF||Decrements the cursor's state?
|-
|$07||SO_USERPUT_SOFT_ON||Increments "user input" counter (when greater than 0, user input is enabled).
|-
|$08||SO_USERPUT_SOFT_OFF||Decrements "user input" counter (when 0 or less, user input is disabled).
|-
|$0A||SO_CURSOR_IMAGE||Changes the cursor image to a new one, based on image in a character set. Only used in Loom.
|-
|$0B||SO_CURSOR_HOTSPOT||Changes the hotspot of a cursor. Only used in Loom.
|-
|$0C||SO_CURSOR_SET||Changes the current cursor. Must be between 0 and 3 inclusive.
|-
|$0D||SO_CHARSET_SET||Initializes the given character set.
|-
|$0E||SO_CHARSET_COLORS||Initializes the character set data & colours to the given arguments? Must have 16 arguments?
|}
===Variants===
In SCUMM V3, sub-opcode $0E performs a different function, to load/initialize a character set.
opcode $0E arg1[p8] arg2[p8]
==cutScene ($40)==
===Encoding===
opcode args[v16]...
===Operation===
??? If required, runs a script passing the given arguments. Cutscene data given by the first argument?
==debug ($6B)==
one parameter, no result
===Encoding===
opcode param[p16]
===Operation===
Passes the parameter to the interpreter's debugger. What this does is entirely platform-specific (and may do nothing).
==decrement ($C6)==
no parameters, uses result
===Encoding===
opcode result
===Operation===
result := result - 1
Reads the variable pointed to by result, decrements it, and writes it back.
==delay ($2E)==
one constant parameter
===Encoding===
opcode param[24]
===Operation===
Suspends the current thread for the appropriate number of 1/60ths of a second. Yes, that really is a 24-bit LE constant.
==delayVariable ($2B)==
one constant parameter
===Encoding===
opcode var
===Operation===
var is dereferenced and the current thread suspended for that number of 1/60ths of a second.
==divide ($5B)==
one parameter, uses result
===Encoding===
opcode result value[p16]
===Operation===
result := result / value
The variable pointed to by result is read, divided by value, and the result written back. If value is zero, the result is undefined (and the interpeter may halt with an error).
==doSentence ($19)==
===Encoding===
opcode verb[p8] objectA[p16] objectB[p16]
===Operation===
Performs a verb sentence action, e.g. "Use monkey on hydrant". If verb is $FE, the current sentence script is stopped, status cleared etc.
==drawBox ($3F)==
two parameters, does not use result, supplementary opcode byte with three more subsequent parameters
===Encoding===
opcode left[p16] top[p16] auxopcode[8] right[p16] bottom[p16] colour[p8]
===Operation===
Draws a solid box on the backbuffer from (left, top)-(right, bottom) in the given colour.
The only part of auxopcode that is relevant are the parameter bits. The rest of the opcode is ignored.
==drawObject ($05)==
===Encoding===
opcode object[p16] sub-opcode
sub-opcodes:
$01 xpos[p16] ypos[p16]
$02 state[p16]
$1F
===Operation===
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||Draw At||Moves the given object to the given co-ordinates, and adds it to the drawing queue.
|-
|$02||Set State||Sets the state of the object, adds it to the drawing queue.
|-
|$1F||Draw||Does not change the object's position (or state?), still adds it to the drawing queue.
|}
===Variants===
Small header games only support the parameters used with sub-opcode $01, e.g:
opcode object[p16] xpos[p16] ypos[p16]
==dummy ($A7)==
===Encoding===
opcode
===Operation===
V5 specific - The KIXX XL release of Monkey Island 2 (Amiga disk) used this opcode as a dummy, in order to remove copy protection and keep level selection.
===Variants===
In SCUMM V3 and V4, this opcode is used for the saveLoadVars instruction.
==endCutScene ($C0)==
===Encoding===
opcode
===Operation===
Ends the cutscene, performing cleanup if necessary.
==equalZero ($28)==
jumps
===Encoding===
opcode var target[16]
===Operation===
unless (var == 0) goto target
Target is a byte offset (measured from after this instruction), which will be added to the instruction pointer.
==expression ($AC)==
===Encoding===
opcode result subopcode... $FF
sub-opcodes:
$01 value[p16]
$02
... $02 through $05 take the same arguments ...
$05
$06 nested-opcode
===Operation===
Expression mode operates on a stack. Values are pushed on, and operators are applied to the top two items on the stack.
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||Value||Pushes a value onto the top of the stack.
|-
|$02||Add||stack[top - 1] + stack[top]
|-
|$03||Subtract||stack[top - 1] - stack[top]
|-
|$04||Multiply||stack[top - 1] * stack[top]
|-
|$05||Divide||stack[top - 1] / stack[top]  (if stack[top] is 0 an error occurs)
|-
|$06||Nested Opcode||An entire instruction that returns a result, such as getActorScale. This is interpreted like a normal opcode, but the result is pushed onto the expression stack. (The opcode is passed the special "VAR_RESULT" parameter for "result")
|}
==faceActor ($09)==
===Encoding===
opcode actor[p8] object[p16]
===Operation===
Dereferences actor, tells actor to face object (presumably based on X/Y co-ordinates).
==findInventory ($3D)==
===Encoding===
opcode result owner[p8] index[p8]
===Operation===
object := owner.inventory[index]
Searches for all objects owned by owner (an actor or object), and returns the one at the given index (offset).
==findObject ($35)==
===Encoding===
opcode result x[p8] y[p8]
===Operation===
Returns the first "touchable" local object at the given co-ordinates. Will not match on the bottom or right-hand edges of an object.
==freezeScripts ($60)==
===Encoding===
opcode flag[p8]
===Operation===
Freezes all scripts (by setting the high bit on each script's status). If flag is >= $80, all freeze resistent scripts will also be frozen. If flag is 0, all scripts are unfrozen. Freezing effects are cumulative - i.e. if script A is frozen twice, and unfrozen once, it will still be frozen until it is unfrozen a second time. A script's frozen status is indicated by the high bit.
==getActorCostume ($71)==
===Encoding===
opcode result actor[p8]
===Operation===
Returns the actor's current costume.
==getActorElevation ($06)==
===Encoding===
opcode result actor[p8]
===Operation===
Returns the actor's current elevation.
==getActorFacing ($63)==
===Encoding===
opcode result actor[p8]
===Operation===
Returns the current direction the actor is facing.
==getActorMoving ($56)==
===Encoding===
opcode result actor[p8]
===Operation===
Returns the actor's moving status (0 or 1).
==getActorRoom ($03)==
===Encoding===
opcode result actor[p8]
===Operation===
Returns the room the actor currently occupies?
==getActorScale ($3B)==
===Encoding===
opcode result actor[p8]
===Operation===
Returns the actor's current scale.
===Variants===
In Indy3, this opcode is used for waitForActor.
==getActorWalkBox ($7B)==
===Encoding===
opcode result actor[p8]
===Operation===
Returns the actor's walkbox.
==getActorWidth ($6C)==
===Encoding===
opcode result actor[p8]
===Operation===
Returns the actor's width.
==getActorX ($43)==
===Encoding===
opcode result actor[p16]
===Operation===
Returns the actor's current X co-ordinate.
===Variants===
In Indy3, actor is only one byte.
opcode result actor[p8]
==getActorY ($23)==
===Encoding===
opcode result actor[p16]
===Operation===
Returns the actor's current Y co-ordinate.
===Variants===
In Indy3, actor is only one byte.
opcode result actor[p8]
==getAnimCounter ($22)==
===Encoding===
opcode result actor[p8]
===Operation===
Returns the actor's animation counter.
===Variants===
This opcode is used for saveLoadGame in SCUMM V3.
==getClosestObjActor ($66)==
===Encoding===
opcode result actor[p16]
===Operation===
Returns the object closest to the actor. Items that are more than 255 units (pixels in newer games, characters in older games) away from the actor will not be detected.
==getDist ($34)==
===Encoding===
opcode result objA[p16] objB[p16]
===Operation===
Returns the distance between two actors/objects (objA and objB).
==getInventoryCount ($31)==
===Encoding===
opcode result actor[p8]
===Operation===
Returns the number of items in an actor's inventory?
==getObjectOwner ($10)==
===Encoding===
opcode result object[p16]
===Operation===
Returns the owner of an object.
==getObjectState ($0F)==
===Encoding===
opcode result object[p16]
===Operation===
Returns the state of the object.
===Variants===
In small header games, the encoding becomes:
opcode object[p16] state[p8] target[16]
operation becomes
unless (getState(object) == state) goto target
==getRandomNumber ($16)==
===Encoding===
opcode result seed[p8]
===Operation===
Returns a new random number based on the given seed.
==getScriptRunning ($68)==
===Encoding===
opcode result script[p8]
===Operation===
Returns 1 if the given script is running, 0 if it's not.
==getStringWidth ($67)==
===Encoding===
opcode result strptr[p8]
===Operation===
Gets the length of the string pointed to by strptr (either a variable or direct byte), stores the returned value in result.
==getVerbEntryPoint ($0B)==
===Encoding===
opcode result object[p16] verb[p16]
===Operation===
Returns the entry point for the response code/script for when the given verb is applied to the given object? i.e. gets the start of the script to run for the specific user interaction.
==ifClassOfIs ($1D)==
jumps
===Encoding===
opcode value[p16] args[p16]... $FF target[16]
===Operation===
unless (value.class is one of [args.class]) goto target
Compares the value's class with all classes given in args.
Target is a byte offset (measured from after this instruction), which will be added to the instruction pointer.
==ifNotState ($2F)==
===Encoding===
opcode object[p16] state[p8] target[16]
===Operation===
unless (stateOf(object) != state) goto target
==ifState ($4F)==
===Encoding===
opcode object[p16] state[p8] target[16]
===Operation===
unless (stateOf(object) == state) goto target
==increment ($46)==
no parameters, uses result
===Encoding===
opcode result
===Operation===
result := result + 1
Reads the variable pointed to by result, increments it, and writes it back.
==isActorInBox ($1F)==
===Encoding===
opcode actor[p8] box[p8] target[16]
===Operation===
Unless the actor's co-ordinates are within the bounds of the given box, jump to target.
Target is a byte offset (measured from after this instruction), which will be added to the instruction pointer.
==isEqual ($48)==
===Encoding===
opcode var value[p16] target[16]
===Operation===
unless (value == var) goto target
Target is a byte offset (measured from after this instruction), which will be added to the instruction pointer.
==isGreater ($78)==
===Encoding===
opcode var value[p16] target[16]
===Operation===
unless (value > var) goto target
Target is a byte offset (measured from after this instruction), which will be added to the instruction pointer.
==isGreaterEqual ($04)==
===Encoding===
opcode var value[p16] target[16]
===Operation===
unless (value >= var) goto target
Target is a byte offset (measured from after this instruction), which will be added to the instruction pointer.
==isLess ($44)==
===Encoding===
opcode var value[p16] target[16]
===Operation===
unless (value < var) goto target
Target is a byte offset (measured from after this instruction), which will be added to the instruction pointer.
==isNotEqual ($08)==
===Encoding===
opcode var value[p16] target[16]
===Operation===
unless (value != var) goto target
Target is a byte offset (measured from after this instruction), which will be added to the instruction pointer.
==isSoundRunning ($7C)==
===Encoding===
opcode result sound[p8]
===Operation===
Returns 1 if sound is running, returns 0 if sound is not running or if the given sound is 0.
==jumpRelative ($18)==
jumps
===Encoding===
opcode target[16]
===Operation===
PC := PC + target
The inline constant target is read as a signed word and added to the program counter after the instruction has been read. Therefore, if target is zero, the instruction will do nothing; if target is -3, an infinite loop will result.
==lessOrEqual ($38)==
jumps
===Encoding===
opcode var value[p16] target[16]
===Operation===
unless (value <= var) goto target
Target is a byte offset (measured from after this instruction), which will be added to the instruction pointer.
==lights ($70)==
===Encoding===
opcode arg1[p8] arg2[8] arg3[8]
===Operation===
If arg3 is 0, the "current lights" variable is set to arg1.
If arg3 is 1, the size of the "flashlight" light is determined by arg1 and arg2, for width and height in stripes (which are equivalent to 8 pixels each; see [[SCUMM/Technical Reference/Image resources]]).
==loadRoom ($72)==
===Encoding===
opcode room[p8]
===Operation===
Loads the given room into memory.
==loadRoomWithEgo ($24)==
===Encoding===
opcode object[p16] room[p8] x[16] y[16]
===Operation===
Places the Ego actor in room at object's position. If x is not -1, Ego will start moving towards the given x and y co-ordinates. If object is not in the given room an error will occur.
(I think...)
==matrixOp ($30)==
===Encoding===
opcode sub-opcode
sub-opcodes:
$01 box[p8] val[p8]
$02 box[p8] val[p8]
$03 box[p8] val[p8]
$04
===Operation===
This instruction manipulates boxes.
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||setBoxFlags||Sets the box's flags to the given value.
|-
|$02||setBoxScale||Sets the box's scale.
|-
|$03||setBoxScale||Sets the box's scale to ((val - 1) OR $8000).
|-
|$04||createBoxMatrix||Initializes the matrix of boxes, by determining the distances and shortest paths between boxes.
|}
===Variants===
SCUMM V3 only has the one instruction, which behaves like setBoxFlags:
opcode box[p8] val[8]
==move ($1A)==
===Encoding===
opcode result value[p16]
===Operation===
result := value
Value is moved into result.
==multiply ($1B)==
===Encoding===
opcode result value[p16]
===Operation===
result := result * value
The variable pointed to by result is read, multiplied by value, and written back.
==notEqualZero ($A8)==
===Encoding===
opcode var target[16]
===Operation===
unless (var != 0) goto target
Target is a byte offset (measured from after this instruction), which will be added to the instruction pointer.
==oldRoomEffect ($5C)==
===Encoding===
opcode sub-opcode
sub-opcodes:
$03 effect[p16]
===Operation===
Performs like sub-opcode SO_ROOM_FADE of the roomOps instruction (fade in if effect != 0, otherwise fade out).
This information may not be correct; descumm says if the sub-opcode is 3, to "set" the effect, but if the sub-opcode is anything else to fade in with the given effect.
===Variants===
FM-Towns SCUMM V3 performs a different effect, not fully implemented in ScummVM. At the moment ScummVM just forces a redraw of the screen background.
==or ($57)==
one parameter, uses result
===Encoding===
opcode result value[p16]
===Operation===
result := result or value
The variable pointed to by result is read, logically ORed with value, and the result written back.
==override ($58)==
===Encoding===
opcode sub-opcode
sub-opcodes:
$00
$01 $18 target[16]
===Operation===
If the sub-opcode is 0, marks the end of an override section.
If the sub-opcode is not 0, marks the beginning of an override section.
Overrides are used by cutscenes; if a cutscene is skipped (if the user presses the ESC key), the script will jump by the given target (offset from this instruction).
==panCameraTo ($12)==
===Encoding===
opcode x[p16]
===Operation===
Starts the camera panning to the given x co-ordinate.
==pickupObject ($25)==
===Encoding===
opcode object[p16] room[p8]
===Operation===
Adds the given object (located in the given room) to the Ego actor's inventory.
===Variants===
In SCUMM V3 and V4, this opcode is used for drawObject.
==pickupObjectOld ($50)==
===Encoding===
opcode object[p16]
===Operation===
Adds the given object (located in the given room) to the Ego actor's inventory. If object < 1, an error is raised. If the object is not found or the object is already in the inventory, this function ends gracefully.
==print ($14)==
===Encoding===
opcode actor[p8] sub-opcode
sub-opcodes
$00 xpos[p16] ypos[p16]
$01 colour[p8]
$02 right[p16]
$03 width[p16] height[p16]
$04
$06
$07
$08 offset[p16] delay[p16]
$0F string[c]... $FF
===Operation===
Sets text properties and displays dialogue.
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$00||SO_AT||Sets the position of the text that follows.
|-
|$01||SO_COLOR||Sets the colour of the text.
|-
|$02||SO_CLIPPED||Clips the text's right-hand side (for wrapping?).
|-
|$03||SO_ERASE||Erases characters (not used in ScummVM).
|-
|$04||SO_CENTER||Centres the text.
|-
|$06||SO_LEFT||Left-aligns the text.
|-
|$07||SO_OVERHEAD||Overhead-aligns the text.
|-
|$0F||SO_TEXTSTRING||Prints the text string that follows. Terminated by $FF.
|}
===Variants===
In SCUMM V3, text function $06 sets the height of the text:
$06 height[p16]
In Loom CD (SCUMM V4), there is an additional text function $08 (SO_SAY_VOICE), which plays a portion of the CD audio track.
$08 offset[p16] delay[p16]
==printEgo ($D8)==
===Encoding===
opcode sub-opcode
===Operation===
Exactly the same as print, except the actor is implicitly Ego. See the entry for "print" for further explanation.
==pseudoRoom ($CC)==
===Encoding===
opcode val[8] res[8]... $00
===Operation===
forall (res) {
  if (res >= $80) {
  _resourceMapper[res & $7F] := val
  }
}
What does this actually do? We may never know.
==putActor ($01)==
===Encoding===
opcode actor[p8] x[p16] y[p16]
===Operation===
Puts the actor at the given co-ordinates.
==putActorAtObject ($0E)==
===Encoding===
opcode actor[p8] object[p16]
===Operation===
Puts the actor at the given object's position. If the object can not be found, a default position is returned (the centre of the screen in ScummVM).
==putActorInRoom ($2D)==
===Encoding===
opcode actor[p8] room[p8]
===Operation===
Puts the actor in the given room.
==resourceRoutines ($0C)==
===Encoding===
opcode sub-opcode
sub-opcodes:
$01 resID[p8]
... $01 through $13 take the same arguments ...
$13 resID[p8]
$14 room[p8] object[p16]
===Operation===
resID is unique only within the resource type (e.g. script 11 will not conflict with sound 11).
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||SO_LOAD_SCRIPT||Loads the given script into memory.
|-
|$02||SO_LOAD_SOUND||Loads the given sound into memory.
|-
|$03||SO_LOAD_COSTUME||Loads the given costume into memory.
|-
|$04||SO_LOAD_ROOM||Loads the given room into memory.
|-
|$05||SO_NUKE_SCRIPT||Obliterates the given script from memory.
|-
|$06||SO_NUKE_SOUND||Obliterates the given sound from memory.
|-
|$07||SO_NUKE_COSTUME||Obliterates the given costume from memory.
|-
|$08||SO_NUKE_ROOM||Obliterates the given room from memory.
|-
|$09||SO_LOCK_SCRIPT||Locks the given script.
|-
|$0A||SO_LOCK_SOUND||Locks the given sound.
|-
|$0B||SO_LOCK_COSTUME||Locks the given costume.
|-
|$0C||SO_LOCK_ROOM||Locks the given room.
|-
|$0D||SO_UNLOCK_SCRIPT||Unlocks the given script.
|-
|$0E||SO_UNLOCK_SOUND||Unlocks the given sound.
|-
|$0F||SO_UNLOCK_COSTUME||Unlocks the given costume.
|-
|$10||SO_UNLOCK_ROOM||Unlocks the given room.
|-
|$11||SO_CLEAR_HEAP||Clears the heap.
|-
|$12||SO_LOAD_CHARSET||Loads the given character set into memory.
|-
|$13||SO_NUKE_CHARSET||Obliterates the given character set from memory.
|-
|$14||SO_LOAD_OBJECT||Loads the given object from the given room resource.
|}
===Variants===
FM-Towns games add the following sub-opcodes (these are not confirmed nor implemented in ScummVM):
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$20||Unknown||Does nothing, not used in-game.
|-
|$21||Unknown||Does nothing, not used in-game.
|-
|$23||CD Volume||Possibly changes the volume of CD tracks (Loom CD). Takes 1 byte.
|-
|$24||Sound Volume||Sets the loudness of a sound resource. Used in Indy3 and Zak. Takes 2 bytes (left/right volumes?).
|-
|$25||Sound Pitch||Sets the pitch of a sound resource. Used in Indy3 and Zak. Takes 1 byte (pitch = "foo" - "center" semitones. Center is at $32 in the sound resource.)
|}
==roomOps ($33)==
===Encoding===
opcode sub-opcode
sub-opcodes:
$01 minX[p16] maxX[p16]
$03 b[p16] h[p16]
$04 red[p16] green[p16] blue[p16] aux index[p8]
$05
$06
$07 scale1[p8] y1[p8] aux scale2[p8] y2[p8] aux slot[p8]
$08 scale[p8] startcolour[p8] endcolour[p8]
$09 loadflag[p8] loadslot[p8]
$0A effect[p16]
$0B redscale[p16] bluescale[p16] greenscale[p16] aux startcolour[p8] endcolour[p8]
$0C redscale[p16] bluescale[p16] greenscale[p16] aux startcolour[p8] endcolour[p8]
$0D resID[p8] filename[c]... $00
$0E resID[p8] filename[c]... $00
$0F resID[p8] aux start[p8] end[p8] aux time[p8]
$10 colindex[p8] delay[p8]
===Operation===
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||SO_ROOM_SCROLL||Clamps the given arguments so scrolling does not extend past the width of the room or screen.
|-
|$03||SO_ROOM_SCREEN||Initialises a screen.
|-
|$04||SO_ROOM_PALETTE||Adjusts the room's palette.
|-
|$05||SO_ROOM_SHAKE_ON||Starts the room shaking.
|-
|$06||SO_ROOM_SHAKE_OFF||Ends the room shaking.
|-
|$07||SO_ROOM_SCALE||Sets the room's y scales? (slot is 1 greater than actual slot?)
|-
|$08||SO_ROOM_INTENSITY||Lightens/darkens the room's palette.
|-
|$09||SO_ROOM_SAVEGAME||Saves temporary state of the room/game?
|-
|$0A||SO_ROOM_FADE||If effect is 0, fades in the room. Otherwise, fades out with the given effect (taken from the high byte of effect).<br>1 = iris effect<br>2 = box wipe (upper-left to bottom-right)<br>3 = box wipe (upper-right to bottem-left)<br>4 = inverse box wipe.
|-
|$0B||SO_RGB_ROOM_INTENSITY||Lightens/darkens the room's palette, with different scales for red, green and blue.
|-
|$0C||SO_ROOM_SHADOW||Lightens/darkens the shadow palette, with different scales for red, green, and blue.
|-
|$0D||SO_SAVE_STRING||Saves a string resource to the given file?
|-
|$0E||SO_LOAD_STRING||Loads a string resource from a given file?
|-
|$0F||SO_ROOM_TRANSFORM||Manipulates palettes, strings?
|-
|$10||SO_CYCLE_SPEED||Starts colour cycling with delay? colIndex is between 0 and 16
|}
===Variants===
SCUMM V3 (non-PC Engine) encodes the arguments before the sub-opcode:
opcode arg1[p16] arg2[p16] sub-opcode
Small header games include an extra sub-opcode, $02 (SO_ROOM_COLOR), which adjusts the room's palette:
opcode $02 colour[p16] index[p16]
... or for V3 games ...
opcode colour[p16] index[p16] $02
In small header games, sub-opcode $04 (SO_ROOM_PALETTE) affects the shadow palette, and only accepts two arguments, a "room colour slot" (palette entry? between 0 and 256) and an index:
opcode $04 colour[p16] index[p16]
... or for V3 games ...
opcode colour[p16] index[p16] $04
In FM-Towns games, sub-opcode $0A performs a different function and has its own sub-opcodes (some unknown and all not yet implemented in ScummVM):
opcode $0A sub-opcode
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$08||||compose kMainVirtScreen over a screen buffer
|-
|$09||||call 0x110:0x20 _ax=0x601 _edx=2
|-
|$0A||||call 0x110:0x20 _ax=0x601 _edx=3
|-
|$0B||||clear screen 0x1C:0x45000 sizeof(640 * 320)
|-
|$0C||||call 0x110:0x20 _ax=0x601 _edx=0
|-
|$0D||||call 0x110:0x20 _ax=0x601 _edx=1
|-
|$10||||enable clearing of a screen buffer in drawBitmap()
|-
|$11||||disable clearing of a screen buffer in drawBitmap()
|-
|$12||||clear a screen buffer
|-
|$13||||enable palette operations (palManipulate(), cyclePalette() etc.)
|-
|$14||||disable palette operations
|-
|$15||||disable clearing of screen 0x1C:0x5000 sizeof(640 * 320) in initScreens()
|-
|$16||||enable clearing of screen 0x1C:0x5000 sizeof(640 * 320) in initScreens()
|-
|$1E||||Unknown
|}
==saveRestoreVerbs ($AB)==
===Encoding===
opcode aux start[p8] end[p8] mode[p8] sub-opcode
sub-opcodes:
$01
$02
$03
===Operation===
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||SO_SAVE_VERBS||For all verbs between start and end, sets the "saveid" to mode.
|-
|$02||SO_RESTORE_VERBS||For all verbs between start and end and matching mode, kills any existing verb, sets the saveid to 0 and generally inits the verb.
|-
|$03||SO_DELETE_VERBS||For all verbs between start and end and matching mode, kills any existing verb.
|}
==setCameraAt ($32)==
===Encoding===
opcode x[p16]
===Operation===
Sets the camera's x position.
==setObjectName ($54)==
===Encoding===
opcode object[p16] name[c]... $00
===Operation===
Sets the given object's name.
==setOwnerOf ($29)==
===Encoding===
opcode object[p16] owner[p8]
===Operation===
Sets the owner of the object.
==setState ($07)==
===Encoding===
opcode object[p16] state[p8]
===Operation===
Sets the state of the object.
==setVarRange ($26)==
non-standard encoding
===Encoding===
opcode result number[8] values[8]...
or
opcode result number[8] values[16]...
===Operation===
for (i = 0; i < number; i++) {
  &#42;result + i := values[i];
}
This sets a number of variables to the given parameters. The starting variable is given as "result", and the number of variables to modify is given as "number". This is followed by the same number of values, which will be put into the variable locations. The values are constants, and can be either 16-bit, if the highest bit of the opcode is set, i.e. $A6; or 8-bit, if the highest bit of the opcode is not set, i.e. $26. Note that all values are affected by the opcode's high bit; you can't mix 8 and 16-bit values.
descumm example:
setVarRange(Var[178],9,[0,0,0,0,0,0,0,0,0]);
This sets variables 178 to 186 (inclusive) to 0.
==soundKludge ($4C)==
===Encoding===
opcode items[v16]...
===Operation===
If the first item is -1, the existing sound queue is processed. Otherwise, the list of items is added to the queue.
===Variants===
In SCUMM V3 (small header) games, this opcode is used for the WaitForSentence instruction.
==startMusic ($02)==
===Encoding===
opcode music[p8]
===Operation===
Adds the music in to the queue to be played.
===Variants===
In FM-Towns (SCUMM V3) games, this instruction performs different functions (some kind of Audio CD status query function; some partially implemented in ScummVM):
opcode result sub-opcode
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$00||Is Playing||Returns true if a CD audio track is currently playing.
|-
|$FC||Unpause CD||Unpauses the CD audio track.
|-
|$FD||Pause CD||Pauses the CD audio track.
|-
|$FE||Get CD Sound||Returns the current CD sound.
|-
|$FF||CD Volume||Might return the the current CD volume in FM-Towns Loom.
|-
|other||Track Length||Returns the track length in seconds.
|}
==startObject ($37)==
===Encoding===
opcode object[p16] script[p8] args[v16]...
===Operation===
Starts the object's script (OBCD blocks), passing the given arguments.
==startScript ($0A)==
one parameter plus varargs, extra encoding in opcode
===Encoding===
opcode script[p8] args[v16]...
===Operation===
Spawns a new thread running the code in script script. The new script has its local variables initialised to the list args. Uninitialised variables have undefined values.
The opcode carries extra information:
{| border="1" cellpadding="2" width=10%
|- style="background:whitesmoke"
|7||6||5||4  0
|-
|P1||R||F||$0A
|}
P1 = standard parameter bit<br>
R = indicates that the script is recursive<br>
F = indicates that the script is freeze resistant (a call to freezeScripts will skip this script, unless the "force freeze" bit of the freezeScripts opcode is set).
==startSound ($1C)==
===Encoding===
opcode sound[p8]
===Operation===
Adds the given sound to the sound queue to be played.
==stopMusic ($20)==
===Encoding===
opcode
===Operation===
Stops all sounds.
==stopObjectCode ($00)==
===Encoding===
opcode
===Operation===
Marks the calling script as dead, to be later pruned from the thread pool. Cleans up residual arrays.
==stopObjectScript ($6E)==
===Encoding===
opcode script[p16]
===Operation===
Marks the given object script as dead, to be later pruned from the thread pool. Cleans up residual arrays.
==stopScript ($62)==
===Encoding===
opcode script[p8]
===Operation===
Marks the given script as dead, to be later pruned from the thread pool. Cleans up residual arrays.
==stopSound ($3C)==
===Encoding===
opcode sound[p8]
===Operation===
Stops the given sound.
==stringOps ($27)==
parameters depend on sub-opcode
===Encoding===
opcode sub-opcode
sub-opcodes:
$01 stringID[p8] string[c]... $00
$02 destID[p8] srcID[p8]
$03 stringID[p8] index[p8] char[c]
$04 result stringID[p8] index[p8]
$05 stringID[p8] size[p8]
===Operation===
Miscellaneous actions on strings (Arrays, referred to by resource number).
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||Load String||Loads the inline null-terminated string into the resource slot given by stringID.
|-
|$02||Copy String||Creates a duplicate of the string at resource slot srcID into destID. The old string at destID is lost.
|-
|$03||Write Character||Writes char at the given index (offset) of the string resource located at slot stringID. Out of bounds accesses cause undefined behaviour.
|-
|$04||Read Character||Reads a byte (character) at the given index (offset) of the string resource located at slot stringID, and writes it to result. Out of bounds accesses cause undefined behaviour.
|-
|$05||New String||Allocates or frees a string (Array), located at resource slot stringID. The string is initialised to size; if size is zero, the string is freed.
|}
==subtract ($3A)==
===Encoding===
opcode result value[p16]
===Operation===
result := result - value
The variable pointed to by result is read, value is subtracted from it, and the result written back.
==systemOps ($98)==
===Encoding===
opcode sub-opcode
sub-opcodes:
$01
$02
$03
===Operation===
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||SO_RESTART||Restarts the game.
|-
|$02||SO_PAUSE||Pauses/unpauses the game.
|-
|$03||SO_QUIT||Quits the game.
|}
==verbOps ($7A)==
===Encoding===
opcode verbID[p8] sub-opcode... $FF
sub-opcodes:
$01 object[p16]
$02 name[c]... $00
$03 colour[p8]
$04 hicolour[p8]
$05 left[p16] top[p16]
$06
$07
$08
$09
$10 colour[p8]
$11
$12 key[p8]
$13
$14 stringID[p16]
$16 object[p16] room[p8]
$17 colour[p8]
===Operation===
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||SO_VERB_IMAGE||Assigns an object (image) to a verb.
|-
|$02||SO_VERB_NAME||Assigns the in-line name to the verb slot.
|-
|$03||SO_VERB_COLOR||Sets the colour of the verb.
|-
|$04||SO_VERB_HICOLOR||Sets the high colour of the verb.
|-
|$05||SO_VERB_AT||Sets the verb's top-left co-ordinates.
|-
|$06||SO_VERB_ON||Makes this verb active.
|-
|$07||SO_VERB_OFF||Makes this verb inactive.
|-
|$08||SO_VERB_DELETE||Kills this verb.
|-
|$09||SO_VERB_NEW||Creates a verb in the slot for the given verbID. If the slot is 0 (verb doesn't already exist), will add it to the next unusued slot; if this exceeds the global maximum number of verbs an error will be raised.
|-
|$10||SO_VERB_DIMCOLOR||Sets the dim colour of the verb.
|-
|$11||SO_VERB_DIM||Dims this verb.
|-
|$12||SO_VERB_KEY||Sets the key code (maybe ASCII char?) associated with this verb.
|-
|$13||SO_VERB_CENTER||Centres the verb?
|-
|$14||SO_VERB_NAME_STR||Loads the given string resource into the verb's slot. If either the string resource or verb slot is not found (0), the verb resource is nuked.
|-
|$16||Assign Object||Assigns an object from the given room to the verb (if the object's image index is not already assigned to the given object).
|-
|$17||Set Back Colour||Sets the background colour of the verb?
|}
==wait ($AE)==
===Encoding===
opcode sub-opcode
sub-opcodes:
$01 actor[p8]
$02
$03
$04
===Operation===
{| border="1" cellpadding="2" width=100%
|- style="background:whitesmoke"
|Opcode||Meaning||Description
|-
|$01||SO_WAIT_FOR_ACTOR||If the given actor is moving, breaks and resumes at this instruction again.
|-
|$02||SO_WAIT_FOR_MESSAGE||If the global variable VAR_HAVE_MSG (Var[3]) is not zero, breaks and resumes at this instruction again.
|-
|$03||SO_WAIT_FOR_CAMERA||If the camera has not reached its destination x position, breaks and resumes at this instruction again.
|-
|$04||SO_WAIT_FOR_SENTENCE||If there is a sentence present?, breaks and resumes at this instruction again
|}
===Variants===
In Indy3 (non-Macintosh), this opcode only acts as SO_WAIT_FOR_MESSAGE and omits the sub-opcode.
opcode
==walkActorTo ($1E)==
===Encoding===
opcode actor[p8] x[p16] y[p16]
===Operation===
Sets the actor to begin walking to the given position.
==walkActorToActor ($0D)==
===Encoding===
opcode walker[p8] walkee[p8] distance[8]
===Operation===
Walks walker towards walkee's position by the given distance. Walker and walkee are both actors.
==walkActorToObject ($36)==
===Encoding===
opcode actor[p8] object[p16]
===Operation===
Sets the actor to begin walking to the given object's position.
=Variables=
A number of variables are reserved for use by the SPUTM/SCUMM engine. Here is a list of known variables and their corresponding numbers, taken from the ScummVM source code.
VAR_RESULT = 0; // descumm claims var 0 is the result var (for expressions)
VAR_KEYPRESS = 0; // script_v5_.cpp claims var 0 is for keypresses...
VAR_EGO = 1;
VAR_CAMERA_POS_X = 2;
VAR_HAVE_MSG = 3;
VAR_ROOM = 4;
VAR_OVERRIDE = 5;
VAR_MACHINE_SPEED = 6;
VAR_ME = 7;
VAR_NUM_ACTOR = 8;
VAR_CURRENT_LIGHTS = 9;
VAR_CURRENTDRIVE = 10;
VAR_TMR_1 = 11;
VAR_TMR_2 = 12;
VAR_TMR_3 = 13;
VAR_MUSIC_TIMER = 14;
VAR_ACTOR_RANGE_MIN = 15;
VAR_ACTOR_RANGE_MAX = 16;
VAR_CAMERA_MIN_X = 17;
VAR_CAMERA_MAX_X = 18;
VAR_TIMER_NEXT = 19;
VAR_VIRT_MOUSE_X = 20;
VAR_VIRT_MOUSE_Y = 21;
VAR_ROOM_RESOURCE = 22;
VAR_LAST_SOUND = 23;
VAR_CUTSCENEEXIT_KEY = 24;
VAR_TALK_ACTOR = 25;
VAR_CAMERA_FAST_X = 26;
VAR_SCROLL_SCRIPT = 27;
VAR_ENTRY_SCRIPT = 28;
VAR_ENTRY_SCRIPT2 = 29;
VAR_EXIT_SCRIPT = 30;
VAR_EXIT_SCRIPT2 = 31;
VAR_VERB_SCRIPT = 32;
VAR_SENTENCE_SCRIPT = 33;
VAR_INVENTORY_SCRIPT = 34;
VAR_CUTSCENE_START_SCRIPT = 35;
VAR_CUTSCENE_END_SCRIPT = 36;
VAR_CHARINC = 37;
VAR_WALKTO_OBJ = 38;
VAR_DEBUGMODE = 39;
VAR_HEAPSPACE = 40;
VAR_RESTART_KEY = 42;
VAR_PAUSE_KEY = 43;
VAR_MOUSE_X = 44;
VAR_MOUSE_Y = 45;
VAR_TIMER = 46;
VAR_TIMER_TOTAL = 47;
VAR_SOUNDCARD = 48;
VAR_VIDEOMODE = 49;
VAR_MAINMENU_KEY = 50;
VAR_FIXEDDISK = 51;
VAR_CURSORSTATE = 52;
VAR_USERPUT = 53;
VAR_V5_TALK_STRING_Y = 54;
VAR_SOUNDRESULT = 56;
VAR_TALKSTOP_KEY = 57;
VAR_FADE_DELAY = 59;
VAR_NOSUBTITLES = 60;
VAR_SOUNDPARAM = 64;
VAR_SOUNDPARAM2 = 65;
VAR_SOUNDPARAM3 = 66;
VAR_INPUTMODE = 67; // 1 is keyboard, 2 is joystick, 3 is mouse
VAR_MEMORY_PERFORMANCE = 68;
VAR_VIDEO_PERFORMANCE = 69;
VAR_ROOM_FLAG = 70;
VAR_GAME_LOADED = 71;
VAR_NEW_ROOM = 72;
=Table of Parameters=
Please see the wiki page [[SCUMM/V5_opcodes/Table]].
Jestar jokin
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