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impl bgcnt registers

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Matthew Berry 2020-10-11 12:23:13 -07:00
parent 367b578d9f
commit 403bd71d7e
1 changed files with 33 additions and 0 deletions
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33
src/crab/ppu.cr
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@ -36,12 +36,27 @@ class PPU
bool vblank # todo update bitfield macro to make values read-only when writing to value
end
class BGCNT < BitField(UInt16)
num screen_size, 2
bool screen_overflow
num tile_map, 5
bool colors_palette
bool mosaic
num not_used, 2 # todo update bitfield macro to support locking values, must be 0
num tile_data, 2
num priority, 2
end
getter pram = Bytes.new 0x400
getter vram = Bytes.new 0x18000
getter dispcnt : DISPCNT = DISPCNT.new 0
getter dispstat : DISPSTAT = DISPSTAT.new 0
getter vcount : UInt16 = 0x0000_u16
getter bg0cnt : BGCNT = BGCNT.new 0
getter bg1cnt : BGCNT = BGCNT.new 0
getter bg2cnt : BGCNT = BGCNT.new 0
getter bg3cnt : BGCNT = BGCNT.new 0
def initialize(@gba : GBA)
start_scanline
@ -84,6 +99,16 @@ class PPU
when 0x001 then 0xFF_u8 & @dispcnt.value >> 8
when 0x004 then 0xFF_u8 & @dispstat.value
when 0x005 then 0xFF_u8 & @dispstat.value >> 8
when 0x006 then 0xFF_u8 & @vcount
when 0x007 then 0xFF_u8 & @vcount >> 8
when 0x008 then 0xFF_u8 & @bg0cnt.value
when 0x009 then 0xFF_u8 & @bg0cnt.value >> 8
when 0x00A then 0xFF_u8 & @bg1cnt.value
when 0x00B then 0xFF_u8 & @bg1cnt.value >> 8
when 0x00C then 0xFF_u8 & @bg2cnt.value
when 0x00D then 0xFF_u8 & @bg2cnt.value >> 8
when 0x00E then 0xFF_u8 & @bg3cnt.value
when 0x00F then 0xFF_u8 & @bg3cnt.value >> 8
else raise "Unimplemented PPU read ~ addr:#{hex_str io_addr.to_u8}"
end
end
@ -96,6 +121,14 @@ class PPU
when 0x003 # undocumented - green swap
when 0x004 then @dispstat.value = (@dispstat.value & 0xFF00) | value
when 0x005 then @dispstat.value = (@dispstat.value & 0x00FF) | value.to_u16 << 8
when 0x008 then @bg0cnt.value = (@bg0cnt.value & 0xFF00) | value
when 0x009 then @bg0cnt.value = (@bg0cnt.value & 0x00FF) | value.to_u16 << 8
when 0x00A then @bg1cnt.value = (@bg1cnt.value & 0xFF00) | value
when 0x00B then @bg1cnt.value = (@bg1cnt.value & 0x00FF) | value.to_u16 << 8
when 0x00C then @bg2cnt.value = (@bg2cnt.value & 0xFF00) | value
when 0x00D then @bg2cnt.value = (@bg2cnt.value & 0x00FF) | value.to_u16 << 8
when 0x00E then @bg3cnt.value = (@bg3cnt.value & 0xFF00) | value
when 0x00F then @bg3cnt.value = (@bg3cnt.value & 0x00FF) | value.to_u16 << 8
else raise "Unimplemented PPU write ~ addr:#{hex_str io_addr.to_u8}, val:#{value}"
end
end