Thread: Scripts
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Old January 6th, 2010 (02:34 PM).
Juan
Brazilian with a bad English
 
Join Date: Jun 2007
Location: Pindamonhangaba - SP
Age: 24
Nature: Adamant
Code:
struct Script{
	u8  SubScriptsCount;
	u8  Continue;
	u16 ifFlag;
	u32 THUMBRoutine;
	u32 NextOffset;
	u32 ReturnOffsets[20];
	u32 CommandTablePointer;
	u32 LastCommandPointer;
	u32 MemoryBanks[4];
}

SubScriptsCount: Number of scripts 'called' by "call" or "callstd".
Continue: If 0 the script ends, else the script continues.
ifFlag: Results of comparisons(compare, checkflags, etc). Used with the 'if' statements(0 = '<' || 1 = '=' || 2 = '>').
THUMBRoutine: A THUMB Routine?
NextOffset: Offset of next byte to be read.
ReturnOffsets: Array of return offsets(command 'return').
CommandTablePointer: Pointer to command table.
LastCommandPointer: Pointer to the last existing one.
MemoryBanks: Places to store data(loadpointer aka messagebox).


The script structure is located in RAM.
In BPRE, is located in 0x03000EB0.
In BPEE, 0x03000E40

I'm not too sure what the thumb routine do, because I did not get to check it out.


Each command is represented by one byte.
Each byte read is added '1'(one) to NextOffset.



"Script Routine":

Code:
ROM:08069804
ROM:08069804 @ ¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦ S U B R O U T I N E ¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦
ROM:08069804	Parameters:	r0 = Script struct Pointer
ROM:08069804
ROM:08069804
ROM:08069804 Scripts:                                @ CODE XREF: sub_8069AA8+14p
ROM:08069804                 PUSH    {R4,LR}
ROM:08069806                 ADD     R4, R0, #0
ROM:08069808                 LDRB    R0, [R4,#1]     @Script.Continue
ROM:0806980A                 CMP     R0, #1
ROM:0806980C                 BEQ     loc_8069842
ROM:0806980E                 CMP     R0, #1
ROM:08069810                 BGT     loc_8069818
ROM:08069812                 CMP     R0, #0          
ROM:08069814                 BEQ     loc_8069834
ROM:08069816                 B       loc_806987A
ROM:08069818 @ ---------------------------------------------------------------------------
ROM:08069818
ROM:08069818 loc_8069818:                            @ CODE XREF: Scripts+Cj
ROM:08069818                 CMP     R0, #2
ROM:0806981A                 BNE     loc_806987A
ROM:0806981C                 LDR     R0, [R4,#4]     @Script.THUMBRoutine
ROM:0806981E                 CMP     R0, #0
ROM:08069820                 BEQ     loc_806983E
ROM:08069822                 BL      bx_r0
ROM:08069826                 LSL     R0, R0, #0x18
ROM:08069828                 LSR     R0, R0, #0x18
ROM:0806982A                 CMP     R0, #1
ROM:0806982C                 BNE     loc_806987A
ROM:0806982E                 STRB    R0, [R4,#1]     @Script.Continue
ROM:08069830                 B       loc_806987A
ROM:08069832 @ ---------------------------------------------------------------------------
ROM:08069832
ROM:08069832 loc_8069832:                            @ CODE XREF: Scripts+42j
ROM:08069832                 STRB    R2, [R4,#1]     @Script.Continue
ROM:08069834
ROM:08069834 loc_8069834:                            @ CODE XREF: Scripts+10j
ROM:08069834                 MOV     R0, #0
ROM:08069836                 B       loc_806987C
ROM:08069838 @ ---------------------------------------------------------------------------
ROM:08069838
ROM:08069838 loc_8069838:                            @ CODE XREF: Scripts+64j
ROM:08069838                 MOV     R0, #0
ROM:0806983A                 STRB    R0, [R4,#1]     @Script.Continue
ROM:0806983C                 B       loc_806987C
ROM:0806983E @ ---------------------------------------------------------------------------
ROM:0806983E
ROM:0806983E loc_806983E:                            @ CODE XREF: Scripts+1Cj
ROM:0806983E                 MOV     R0, #1
ROM:08069840                 STRB    R0, [R4,#1]     @Script.Continue
ROM:08069842
ROM:08069842 loc_8069842:                            @ CODE XREF: Scripts+8j
ROM:08069842                                         @ Scripts+74j
ROM:08069842                 LDR     R2, [R4,#8]     @Script.NextOffset
ROM:08069844                 CMP     R2, #0
ROM:08069846                 BEQ     loc_8069832
ROM:08069848                 LDR     R0, =0x83A7244
ROM:0806984A                 LDR     R0, [R0]          @0x0
ROM:0806984C                 CMP     R2, R0
ROM:0806984E                 BNE     loc_8069858
ROM:08069850
ROM:08069850 loc_8069850:                            @ CODE XREF: Scripts+4Ej
ROM:08069850                 SWI     2
ROM:08069852                 B       loc_8069850
ROM:08069852 @ ---------------------------------------------------------------------------
ROM:08069854 off_8069854:    .long unk_83A7244       @ DATA XREF: Scripts+44r
ROM:08069858 @ ---------------------------------------------------------------------------
ROM:08069858
ROM:08069858 loc_8069858:                            @ CODE XREF: Scripts+4Aj
ROM:08069858                 LDRB    R1, [R2]
ROM:0806985A                 ADD     R0, R2, #1
ROM:0806985C                 STR     R0, [R4,#8]
ROM:0806985E                 LSL     R1, R1, #2
ROM:08069860                 LDR     R0, [R4,#0x5C]  @Script.CommandTablePointer
ROM:08069862                 ADD     R1, R0, R1
ROM:08069864                 LDR     R0, [R4,#0x60]  @Script.LastCommandPointer
ROM:08069866                 CMP     R1, R0
ROM:08069868                 BCS     loc_8069838
ROM:0806986A                 LDR     R1, [R1]
ROM:0806986C                 ADD     R0, R4, #0
ROM:0806986E                 BL      sub_81E3BAC
ROM:08069872                 LSL     R0, R0, #0x18
ROM:08069874                 LSR     R0, R0, #0x18
ROM:08069876                 CMP     R0, #1
ROM:08069878                 BNE     loc_8069842
ROM:0806987A
ROM:0806987A loc_806987A:                            @ CODE XREF: Scripts+12j
ROM:0806987A                                         @ Scripts+16j ...
ROM:0806987A                 MOV     R0, #1
ROM:0806987C
ROM:0806987C loc_806987C:                            @ CODE XREF: Scripts+32j
ROM:0806987C                                         @ Scripts+38j
ROM:0806987C                 POP     {R4}
ROM:0806987E                 POP     {R1}
ROM:08069880                 BX      R1
ROM:08069880 @ End of function Scripts
ROM:08069880
ROM:08069880 @ ---------------------------------------------------------------------------
ROM:08069882                 .byte    0
ROM:08069883                 .byte    0

Now to 'call' a script from an ASM routine, you should do something like:

Code:
main:
	push {r0, r4, lr}
	ldr r0,= 0x03000EB0	@Script Struct
	mov r4, #1
	strb r4, [r0,#1]	@Script.Continue
	ldr r4,= 0x08165862	@Custon script offset
	str r4, [r0,#8]		@Script.NextOffset
	bl CallScript
	pop {r0, r4}
	pop {r1}
	bx r1

CallScript:
	ldr r4,= 0x08069805	@Script Routine (BPGE)
	bx r4
I think this "answers" a question of JPAN, and some "The Follow Me Script" topic.

Spoiler:

Quote originally posted by JPAN:
  • (ultimate goal) It is possible, but how can we create items that execute scripts.


I hope this helps someone with something. :D

And I hope someone they can collaborate to add more things in the 'article'. :P
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