diff options
Diffstat (limited to 'src/background.s')
| -rw-r--r-- | src/background.s | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/src/background.s b/src/background.s index 0facde6..369def9 100644 --- a/src/background.s +++ b/src/background.s @@ -107,4 +107,58 @@ ;; End of the list. .byte $FF + + ;; Clear out the shuttle from the background. + ;; + ;; NOTE: this should only be called from NMI code. + .proc clear_shuttle + ;; The low part of the rocket. + bit PPU::m_status + ldx #$2B + stx PPU::m_address + ldx #$15 + stx PPU::m_address + sta PPU::m_data + sta PPU::m_data + + ;; High part of the rocket. + bit PPU::m_status + ldy #$2A + sty PPU::m_address + ldx #$75 + stx PPU::m_address + sta PPU::m_data + sta PPU::m_data + + bit PPU::m_status + sty PPU::m_address + ldx #$95 + stx PPU::m_address + sta PPU::m_data + sta PPU::m_data + + bit PPU::m_status + sty PPU::m_address + ldx #$B5 + stx PPU::m_address + sta PPU::m_data + sta PPU::m_data + + ;; Middle part of the rocket. + bit PPU::m_status + sty PPU::m_address + ldx #$D5 + stx PPU::m_address + sta PPU::m_data + sta PPU::m_data + + bit PPU::m_status + sty PPU::m_address + ldx #$F5 + stx PPU::m_address + sta PPU::m_data + sta PPU::m_data + + rts + .endproc .endscope |