Add GBC Link, update Masks directory

Masks/gbc_form.asm

@@ -0,0 +1,48 @@
+org    $3B8000
+incbin gfx/gbc_link.4bpp
+
+UpdateGbcPalette:
+{
+  REP #$30   ; change 16bit mode
+  LDX #$001E
+
+  .loop
+  LDA.l GameboyLinkPalette, X : STA $7EC6E0, X
+  DEX : DEX : BPL .loop
+
+  SEP #$30 ; go back to 8 bit mode
+  INC $15  ; update the palette
+  RTL      ; or RTS depending on where you need it
+}
+
+GameboyLinkPalette:
+{
+dw #$0000, #$7FFF, #$237E, #$B711, #$369E, #$14A5, #$01FF, #$1078, #$46FF
+dw #$22A2, #$3B68, #$0A4A, #$12EF, #$2A5C, #$1571, #$7A18, #$7FFF
+dw #$237E, #$B711, #$369E, #$14A5, #$01FF, #$1078, #$46FF, #$7E03
+dw #$7691, #$2678, #$435C, #$1199, #$7A18, #$7FFF, #$237E, #$B711
+dw #$369E, #$14A5, #$01FF, #$1078, #$46FF, #$147F, #$457E, #$6DF3
+dw #$7EB9, #$2A5C, #$2227, #$7A18, #$7FFF, #$237E, #$B711, #$369E
+dw #$14A5, #$01FF, #$1078, #$46FF, #$05FF, #$3B68, #$0A4A, #$12EF
+dw #$567E, #$1872, #$7A18, #$5276, #$0352
+}
+
+LinkState_GameboyForm:
+{
+  CLC
+  LDA $0FFF : BEQ .return ; not in dark world
+
+  ; %PlayerTransform()
+
+  JSL UpdateGbcPalette
+  LDA #$3B : STA $BC                  ; change link's sprite 
+  LDA #$06 : STA $02B2
+  BRA .return
+
+.return
+  LDA $BC : CMP.b #$06 : BNE .not_gbc
+  LDA #$10 : STA $BC
+.not_gbc
+  CLC
+  RTL
+}