split_second/initialize_attributes.asm at master · skadiet/split_second · GitHub

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LoadAttribute:
  LDA $2002             ; read PPU status to reset the high/low latch
  LDA #$23
  STA $2006             ; write the high byte of $23C0 address
  LDA #$C0
  STA $2006             ; write the low byte of $23C0 address
  LDX #$00              ; start out at 0
LoadAttributeLoop:
  LDA game_attributes, x      ; load data from address (attribute + the value in x)
  STA $2007             ; write to PPU
  INX                   ; X = X + 1
  CPX #$40              ; Compare X to hex $40, decimal 64
  BNE LoadAttributeLoop  ; Branch to LoadAttributeLoop if compare was Not Equal to zero
                        ; if compare was equal to 128, keep going down

LoadAttribute2:
  LDA $2002             ; read PPU status to reset the high/low latch
  LDA #$27
  STA $2006             ; write the high byte of $23C0 address
  LDA #$C0
  STA $2006             ; write the low byte of $23C0 address
  LDX #$00              ; start out at 0
LoadAttributeLoop2:
  LDA intro_attributes, x      ; load data from address (attribute + the value in x)
  STA $2007             ; write to PPU
  INX                   ; X = X + 1
  CPX #$40              ; Compare X to hex $40, decimal 64
  BNE LoadAttributeLoop2  ; Branch to LoadAttributeLoop if compare was Not Equal to zero
                        ; if compare was equal to 128, keep going down