funclist.txt

LIST OF FUNCTIONS IN AEVILIA GB
This document's purpose is to provide a quick overview of all of Aevilia GB's functions, or at least the most common ones.
All registers not listed under a function's effects are preserved.


rst waitVBlank
	restarts.asm
	Waits until next VBlank.
	Requires VBlank interrupt to be active.
-	Modifies a.

rst isVBlanking
	restarts.asm
	Sets C if and only if VBlanking (except for last scanline).
-	Modifies a.

rst isVRAMOpen
	restarts.asm
	Sets Z if and only if VRAM can be safely accessed.
-	Modifies a.

rst fill
	restarts.asm
	Fills c bytes, starting at hl, with a.
-	Zeroes c.
-	Modifies hl.

rst copy
	restarts.asm
	Copies c bytes from hl to de.
-	Zeroes c.
-	Modifies hl and de.
-	Modifies a.

rst bankswitch
	restarts.asm
	Switches to ROM bank a (and registers switch in HRAM).
	ALWAYS use this to bankswitch !
-	Preserves all registers.

rst copyStr
	restarts.asm
	Copies bytes from hl to de, up to and including the first $00 (NULL) byte.
-	Modifies hl and de.
-	Zeroes a.

rst callHL
	restarts.asm
	Emulates "call [hl]", but crashes if hl doesn't point to ROM.
-	Passes all registers intact to the callee.


VBlankHandler
	handlers.asm
	Handles a VBlank interrupt.
-	Modifies a and bc.
-	If interrupt vector, caller should save a and bc before calling !
-	Doesn't re-enable interrupts by itself, should be done by caller.

UpdateJoypadState
	handlers.asm
	Polls the hardware to update hHeldButtons and hPressedButtons. (And performs soft-reset)
-	Modifies a and bc.
-	Usually called by VBlankHandler, but may be used from any context.

PollJoypad
	handlers.asm
	Polls the hardware and returns polled keys in a.
-	Modifies a.
-	Caller should have set bits 4 or 5 before calling this !
-	Subfunction of UpdateJoypadState, but may be called from any other context if needed.

DMAScript
	handlers.asm
	Performs an OAM DMA and waits until it has completed.
-	Zeroes b.
-	MUST be in HRAM when called ! Otherwise... welp, crash :D
-	To achieve desired effect, call with c = $46 (rDMA & $FF) and a = (SourceOAM >> 8).

STATHandler
	handlers.asm
	Handles a STAT interrupt.
-	Currently only designed for textbox LY=LYC interrupt.
-	Modifies a.


Fill
	home/utilities.asm
	Fills bc bytes starting at hl with a.
-	Zeroes bc and a.
-	Modifies hl.

Copy
	home/utilities.asm
	Copies bc bytes from de to hl.
-	Zeroes bc.
-	Modifies de and hl.
-	Modifies a.

FillVRAMLite
	home/utilities.asm
	Fills c bytes starting at hl with a.
-	Waits when VRAM can't be accessed.
-	Zeroes c.
-	Modifies d and hl.

CopyToVRAM
	home/utilities.asm
	Copies bc bytes from de to hl.
-	Doesn't copy when VRAM can't be accessed.
-	Zeroes bc.
-	Modifies de and hl.
-	Modifies a.

CopyStrToVRAM
	home/utilities.asm
	Copies bytes from hl to de, up to and including the first $00 (NULL) byte.
-	Doesn't copy when VRAM can't be accessed.
-	Zeroes bc.
-	Modifies de and hl.
-	Zeroes a.

OpenSRAM
	home/utilities.asm
	Performs a write to ROM to unlock SRAM.
-	Sets a to $0A.
-	Please don't mind the hackish "db $D6" that saves one byte and maybe nothing in processor time.

CloseSRAM
	home/utilities.asm
	Performs a write to ROM to lock SRAM.
-	Zeroes a.

DelayBCFrames
	home/utilities.asm
	Waits for bc frames to go by.
-	Zeroes a and bc.
-	To delay by a single frame, consider using rst waitVBlank instead.

CallAcrossBanks
	home/utilities.asm
	Call [b:hl] (call the routine in bank b at address hl).
-	Use this when the caller and the callee are in switchable ROM space and in different banks.
-	Only c and de are passed to the callee.

CopyAcrossLite
	home/utilities.asm
	Copy c bytes in bank b starting at hl to de.
-	Zeroes c.
-	Modifies hl and de.
-	Modifies a.

CopyStrAcross
	home/utilities.asm
	Copy bytes in bank b starting at hl to de up to and including the first $00 (NULL) byte.
-	Modifies a, hl and de.
-	Preserves bc... yup. Somehow.

SaveCurRAMBank
	home/utilities.asm
	Push the current RAM bank ID on the stack.
-	Modifies hl.

RestoreRAMBank
	home/utilities.asm
	Used in conjunction with SaveCurRAMBank. I'll let you guess what it does.
-	Modifies a.
-	Modifies hl.

PreventJoypadMovement
	home/utilities.asm
	Increments the joypad movement prevention counter.
-	Cannot overflow.
-	Modifies a.

AllowJoypadMovement
	home/utilities.asm
	Decrements the joypad movement prevention counter.
-	Cannot underflow.
-	Modifies a.

SpeedUpCPU
	home/utilities.asm
	Switches to CPU double speed mode.
-	Modifies a.

SlowDownCPU
	home/utilities.asm
	Switches to CPU normal speed mode.
-	Modifies a.

MultiplyDEByA
	home/utilities2.asm
	Multiplies de by a and puts the result into hl.
-	Detecting overflow would be quite a pain... ensure it doesn't happen, instead.
-	Zeroes a.
-	Modifies de.

DivideHLByDE
	home/utilities2.asm
	Divides hl by de and puts the result into bc.
-	The remainder can be obtained in hl by adding de to hl.
-	Causes an error screen if trying to divide by zero. Won't softlock :)
-	Modifies a and hl.

DivideHLByDE_KnownDE
	home/utilities2.asm
	Performs DivideHLByDE but skips the "division by zero" check.
-	Use only if de is certain to be non-zero before the call. The check is quick enough.

_AtHL_FatalError
	home/utilities2.asm
	Where "rst callHL" jumps to trap jumps to RAM.

FatalError
	home/utilities2.asm
	Prints a fatal error screen.
-	Call with error message ID in a.
-	Save a before that by loading it into wSaveA.

CopyAcross
	home/utilities2.asm
	Copy bc bytes in bank a from hl to de.
-	Zeroes bc.
-	Modifies hl and de.
-	Modifies a.

CopyAcrossToVRAM
	home/utilities2.asm
	Copy bc bytes in bank a from hl to de.
-	Doesn't copy when VRAM can't be accessed.
-	Modifies hl and de.
-	Modifies a.

SwitchRAMBanks
	home/utilities2.asm
	Switches to WRAM bank a.
-	Preserves all registers.

SwitchROMBanks
	home/utilities2.asm
	Saves the current ROM bank on the stack, then switches to ROM bank b.
-	Modifies hl.
-	Modifies a.

RestoreROMBank
	home/utilities2.asm
	Pops a ROM bank ID from the stack, and switches to that ROM bank.
-	Modifies hl.
-	Modifies a.


LoadOBJPalette
	gfx/graphics.asm
	Loads OBJ palette #a with the colors pointed to by hl.
-	Modifies all registers.

LoadOBJPalette_Hook
	gfx/graphics.asm
	Loads OBJ palette #c with the colors pointed to by de.
-	See LoadOBJPalette.

LoadBGPalette
	gfx/graphics.asm
	Loads BG palette #a with the colors pointed to by hl.
-	Modifies all registers.

LoadBGPalette_Hook
	gfx/graphics.asm
	Loads BG palette #c with the colors pointed to by de.
-	See LoadBGPalette.

TransitionToFixedMap
	gfx/graphics.asm
	Copies the currrently displayed tiles (from free mode) and their attributes to the fixed tilemap.
-	Also sets the tilemap mode to fixed map.
-	Assumes the current tilemap mode is free mode.
-	Modifies all registers.

CopyToFixedMap
	gfx/graphics.asm
	Subfunction of TransitionToFixedMap. Copies the data in one VRAM bank.
-	All dashes from TransitionToFixedMap apply here.

EnableTextbox
	gfx/graphics.asm
	Makes the text box do its appearing animation.
-	Even if the text box is already up... or going down.
-	Modifies a.

WaitForTextbox
	gfx/graphics.asm
	Waits until the text box has fully appeared.
-	Will wait even if the text box is closed or closing...
-	Modifies a.

DisableTextbox
	gfx/graphics.asm
	Starts the text box's disappearing animation, and waits until it has been completed.
-	I recommend using this instead of just setting bit 7, because it's a potential mine of bugs.
-	Zeroes a.