PPU: SendBuffersToPPU (Part 1 of 3)

       Name: SendBuffersToPPU (Part 1 of 3)                          [Show more]
       Type: Subroutine
   Category: PPU
    Summary: Send the icon bar nametable and palette data to the PPU, if it has
             changed, before moving on to tile data in part 2
  Deep dive: Drawing vector graphics using NES tiles
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * SendDataNowToPPU calls SendBuffersToPPU
             * SendScreenToPPU calls SendBuffersToPPU


.SendBuffersToPPU

 LDA barPatternCounter  ; If barPatternCounter = 0, then we need to send the
 BEQ SendBarNamesToPPUS ; nametable entries for the icon bar to the PPU, so
                        ; jump to SendBarNamesToPPU via SendBarNamesToPPUS,
                        ; returning from the subroutine using a tail call

 BPL SendBarPattsToPPUS ; If 0 < barPatternCounter < 128, then we need to send
                        ; the pattern data for the icon bar to the PPU, so
                        ; jump to SendBarPattsToPPU via SendBarPattsToPPUS,
                        ; returning from the subroutine using a tail call

                        ; If we get here then barPatternCounter >= 128, so we
                        ; do not need to send any icon bar data to the PPU

                        ; Fall through into part 2 to look at sending tile data
                        ; to the PPU for the rest of the screen