Emoji_200_v1.pbp

; This patch makes it possible to support
; Emoji characters in custom fonts.
; It remaps Emoji range (0x1F6xx) to Letter-like symbols (0x21xx).
;
; This version is buggy and doesn't work.
#ver 200
;!internal

; inject call to our code into
; text_resources_try_load_glyph_metadata proc
2D E9 F0 41 0D 0C 2D 04  04 46 0F 46 16 46
@ 00 2D 3E D1
{
	; was:
	;  CMP R5,0
	;  BNE ret0
	; At this point R1&R7 contain character code to load,
	; and R5 is its hiword.
	; R0,R3 - unused
;	B.W my_code1
	global continue1
	; here R7 must have charcode
	; and R5 must be 0
}

; also inject call into
; text_resources_try_load_glyph_bitmap proc
34 0c 24 04 @ 00 2c 41 d1 {
	; was:
	;  CMP R4, 0
	;  BNE ret0
	; At this point:
	;  R6 (and R1) is codep
	;  R4 is its hiword (should be 0 to continue)
	;  R0,R3 - unused
;	B.W my_code2
	global continue2
}

; and place our code instead of
; cmdAppList:
70 b5 a0 b0 01 24 02 ad  60 1e c0 b2 ? ? ? ?
80 b1 86 68 29 46 30 46  ? ? ? ? 30 46 ? ?
?  ?  50 21 8d e8 21 00  08 4a 0c a8 23 46 ? ?
; cmdWindowDump:
;10 b5 ?4 04 46  58 b1 ?4 08 b1
;?4 20 46 ?4  bd e8 10 40 ?4 10 bd
{
	proc my_code1
	MOV R0, 1
	; prepare registers...
	MOV R3, R5 ; hiword
	MOV R5, 0 ; for continuation: set R5 to 0, as it will be expected by original code
	B.W begin

	global my_code2
	MOV R0, 2
	; prepare...
	MOV R3, R4 ; hiword
	MOV R4, 0 ; for continuation

	begin:
	; here R3 is hiword,
	; R1 is codep
	CMP R3, 0 ; hiword is 0?
	BEQ cont ;just continue - this is not our case (as we have valid lower character)
	LDR R3, diff ; R3 is still unused in proc, so we can use it
	SUB R1, R3 ; now R1 may be valid emoji
	LDR R3, base
	CMP R3, R1
	BHI ret ; if base > char -> char was < than emoji range
	ADD R3, 0x4F ; max emoji char
	CMP R1, R3
	BHI ret ; if > max emoji
	
	cont:
	CMP R0, 1
	BNE cont2
	MOV R7, R1 ; update R7 with new codepoint value, if changed
	B.W continue1
	cont2:
	MOV R6, R1 ; update R6
	B.W continue2

	ret:
	CMP R0, 1
	BNE ret2
	MOV R0, 0
	db BD E8 F0 81 ; POP.W R4-R8,PC
	ret2:
	MOV R0, 0
	db BD E8 FE 83 ; POP.W R1-R9,PC

	; data block:
	ALIGN 4
	;diff: DCD 0x1d500 ; emoji_start - new_base
	;base: DCD 0x2100
	diff: DCD 0x1f5d8 ;0x1F600-0x28
	base: DCD 0x28
}