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-- set cpu to 6502
cpu = require "6502"
setmetatable(_ENV, cpu)
nes = {
OAM = 0x200, -- 0x100 bytes
RAM = 0x300, -- 0x500 bytes + ZP 0x100 bytes + Stack 0x100 bytes + OAM 0x100 bytes = 0x800 bytes
-- 2C02 / 2C07 PPU
PPUCTRL = 0x2000,
PPUMASK = 0x2001,
PPUSTAT = 0x2002,
OAMADDR = 0x2003,
OAMDATA = 0x2004,
BGSCROL = 0x2005,
PPUADDR = 0x2006,
PPUDATA = 0x2007,
-- 2A03 / 2A07 CPU+APU
SQ1VOL = 0x4000,
SQ1SWEEP = 0x4001,
SQ1LO = 0x4002,
SQ1HI = 0x4003,
SQ2VOL = 0x4004,
SQ2SWEEP = 0x4005,
SQ2LO = 0x4006,
SQ2HI = 0x4007,
TRILINEAR = 0x4008,
TRILO = 0x400A,
TRIHI = 0x400B,
NOISEVOL = 0x400C,
NOISELO = 0x400E,
NOISEHI = 0x400F,
DMCFREQ = 0x4010,
DMCRAW = 0x4011,
DMCSTART = 0x4012,
DMCLEN = 0x4013,
OAMDMA = 0x4014,
SNDCNT = 0x4015,
SPECIO1 = 0x4016,
SPECIO2 = 0x4017,
SRAM = 0x6000, -- 0x2000 bytes
ROM = 0x8000, -- 0x8000 bytes
-- PPU Memory declarations
CHAR0 = 0x0000, -- 0x1000 bytes
CHAR1 = 0x1000, -- 0x1000 bytes
SCREEN0 = 0x2000, -- 0x400 bytes
SCREEN1 = 0x2400, -- 0x400 bytes
SCREEN2 = 0x2800, -- 0x400 bytes
SCREEN3 = 0x2C00, -- 0x400 bytes
BGPAL = 0x3F00, -- 0x10 bytes
OBJPAL = 0x3F10, -- 0x10 bytes
}
do
local symbols = cpu.symbols
for k,v in pairs(nes) do symbols[k] = v end
end
-- add some symbol file formats for NES debuggers
cpu.getsym_as.mesen = function() -- .mlb
local ins,fmt = table.insert,string.format
local s = getsym(function(a,l)
if a >= 0x10000 then return end
local prefix = {}
if a < 0x2000 then prefix[1]='R'
elseif a >= 0x6000 and a < 0x8000 then prefix[1]='S' prefix[2]='W' a=a-0x6000
elseif a >= 0x8000 then prefix[1]='P' a=a-0x8000
else prefix[1]='G' end
local s = {}
for _,p in ipairs(prefix) do ins(s, fmt("%s:%04x:%s", p, a, l)) end
return s
end)
return table.concat(s, '\n')
end
cpu.getsym_as.fceux = function(filename) -- .nl, multiple files
local ins,fmt = table.insert,string.format
local ram,rom = {},{}
local s = getsym(function(a,l)
local s = fmt("$%04x#%s#", a, l)
if a < 0x8000 then ins(ram, s)
elseif a < 0x10000 then
local a_org = symbolsorg[l] or a
local bank = math.floor((a_org - 0x8000) / 0x4000)
if not rom[bank] then rom[bank] = {} end
ins(rom[bank], s)
end
end)
local fn = filename
if not fn:find('%.') then fn = fn .. '.nes' end
local fni = fn .. '.ram.nl'
local f = assert(io.open(fni, "wb"), "failed to open " .. fni .. " for writing")
f:write(table.concat(ram, '\n')) f:close()
for k,v in pairs(rom) do
fni = fn .. '.' .. k .. '.nl'
f = assert(io.open(fni, "wb"), "failed to open " .. fni .. " for writing")
f:write(table.concat(v, '\n')) f:close()
end
end
mappers = {}
vblank_waitbegin = function()
local l=label() bit PPUSTAT bpl l
end
vblank_waitend = function()
local l=label() bit PPUSTAT bmi l
end
ppu_addr = function(addr)
lda #addr>>8 sta PPUADDR
if addr&0xff ~= addr>>8 then lda #addr&0xff end
sta PPUADDR
end
oam_bytes = function(t)
return {
t.y - 1,
t.tile,
(t.palette or 0)&3 | ((t.behind or t.priority==1) and 0x20 or 0) | (t.flipx and 0x40 or 0) | (t.flipy and 0x80 or 0),
t.x
}
end
oam_set = function(t)
local b = oam_bytes(t)
lda #t[1]*4 sta OAMADDR
for _,v in ipairs(b) do lda #v sta OAMDATA end
end
oamcache = OAM -- change it to set other location
oamcache_clear = function()
local oam = oamcache
ldx #0 lda #0xff
local l=label() sta oam,x inx inx inx inx bne l
end
oamcache_flush = function()
local oam = oamcache
lda #0 sta OAMADDR lda #oam>>8 sta OAMDMA
end
oamcache_set = function(t)
local oam = oamcache
local b = oam_bytes(t)
ldx #t[1]*4 lda #b[1] sta oam,x
inx lda #b[2] sta oam,x
inx lda #b[3] sta oam,x
inx lda #b[4] sta oam,x
end
--[[ button state:
bit: 7 6 5 4 3 2 1 0
button: A B Select Start Up Down Left Right
https://wiki.nesdev.com/w/index.php/Controller_Reading
]]
-- fast reading of just the A button
-- return C if A is pressed, c otherwise
read_joy_a = function(joy_index)
local joy = joy_index == 2 and SPECIO2 or SPECIO1
lda #1 sta joy lsr sta joy lda joy lsr
end
-- read one joypad state into dst
read_joy = function(dst, joy_index)
local joy = joy_index == 2 and SPECIO2 or SPECIO1
lda #1 sta joy sta dst lsr sta joy
@_readbutton lda joy lsr rol dst bcc _readbutton
end
-- read both joypad states and Famicom's DA15 expansion port
read_joys = function(dst1, dst2)
lda #1 sta SPECIO1 sta dst2 lsr sta SPECIO1
@_readbuttons
lda SPECIO1 and #3 cmp #1 rol dst1
lda SPECIO2 and #3 cmp #1 rol dst2
bcc _readbuttons
end
-- read both joypad states on even cycles only, to safely work with DPCM
-- must be called right after oamcache_flush or any other sta OAMDMA
read_joys_even = function(dst1, dst2)
ldx #1 stx dst1 stx SPECIO1 dex stx SPECIO1
@_readbuttons
lda SPECIO2 and #3 cmp #1 rol dst2,x
lda SPECIO1 and #3 cmp #1 rol dst1
bcc _readbuttons
end
init = function()
sei -- cld not needed, no BCD support
ldx #0x40 stx SPECIO2 -- disable APU frame IRQ
ldx #0xff txs inx stx PPUCTRL stx PPUMASK stx DMCFREQ -- disable NMI, rendering, DMC IRQs
bit PPUSTAT -- clear remnant VBlank PPU status flag on reset
vblank_waitbegin()
lda #0 sta SNDCNT -- stop APU channels
-- clear CPU RAM
@_zeroram
sta 0x0000,x sta 0x0100,x sta 0x0200,x sta 0x0300,x
sta 0x0400,x sta 0x0500,x sta 0x0600,x sta 0x0700,x
inx bne _zeroram
vblank_waitbegin()
-- clear OAM
oamcache_clear() oamcache_flush()
-- clear PPU RAM
bit PPUSTAT ppu_addr(0x2000) tax ldy #0x10
@_zeroppu
sta PPUDATA dex bne _zeroppu dey bne _zeroppu
bit PPUSTAT -- reset latch
if mappers.init then mappers.init() end
end
-- NES 2.0 (backward compatible with iNES)
-- https://wiki.nesdev.com/w/index.php/NES_2.0
header = function(t)
if not t then t = {} end
local logsz = function(sz)
assert(sz >= 0 and sz <= 1048576, "invalid size: " .. sz .. ", expected [0, 1048576]")
if sz < 1 then return 0 end
if sz <= 128 then return 1 end
return math.ceil(math.log(sz/64, 2))
end
-- mapper
local mi1 = t.mapperid or 0
assert(mi1 >= 0 and mi1 < 4096, "invalid mapper id: " .. mi1 .. ", expected [0, 4095]")
local ms1 = t.submapperid or 0
assert(ms1 >= 0 and ms1 < 16, "invalid submapper id: " .. ms1 .. ", expected [0, 15]")
local mapper6 = (mi1 & 0xf) << 4
local mapper7 = mi1 & 0xf0
local mapper8 = (mi1 >> 8) | (ms1 << 4)
-- prgsize
local prgsize = math.tointeger((t.prgsize or 16384) / 16384)
assert(prgsize, "prgsize must be a multiple of 16384")
-- chrsize
local chrsize = math.tointeger((t.chrsize or 0) / 8192)
assert(chrsize, "chrsize must be a multiple of 8192")
-- wramsize (not battery-backed)
local wramsize = logsz(t.wramsize or 0)
-- bramsize (battery-backed)
local bramsize = logsz(t.bramsize or 0)
-- chrbramsize (battery-backed)
local chrbramsize = logsz(t.chrbramsize or 0)
-- chrramsize (not battery-backed)
local chrramsize = logsz(t.chrramsize or (chrbramsize==0 and chrsize==0 and 8192 or 0))
local battery_bit = bramsize == 0 and chrbramsize == 0 and 0 or 2
-- mirror: 'H' for horizontal mirroring, 'V' for vertical mirroring
-- '4' for four-screen VRAM, 218 for four-screen and vertical
local mirror = (t.mirror or 'h'):lower()
mirror = ({ h=0, v=1, ['4']=8, [218]=9 })[mirror]
assert(mirror, "invalid mirror mode: " .. mirror .. ", expected 'H', 'V', '4', or 218")
-- tv: 'N' for NTSC, 'P' for PAL, 'NP' for both preferring NTSC, 'PN' for both preferring PAL
local tv, tvm = 0, (t.tv or 'n'):lower()
assert(tvm=='n' or tvm=='p' or tvm=='np' or tvm=='pn', "invalid tv mode: " .. tostring(t.tv) .. ", expected 'N', 'P', 'NP' or 'PN'")
if tvm[1] == 'p' then tv = 1 end
if #tvm > 1 then tv = tv + 2 end
@@header -- size: 16 bytes
dc.b 0x4e, 0x45, 0x53 -- 'NES'
dc.b 0x1a
dc.b prgsize, chrsize
dc.b mapper6 | mirror | battery_bit
dc.b mapper7 | 8
dc.b mapper8
dc.b ((chrsize >> 4) & 0xF0) | ((prgsize >> 8) & 0x0F)
dc.b (bramsize << 4) | wramsize
dc.b (chrbramsize << 4) | chrramsize
dc.b tv, 0, 0, 0
-- update table with defaulted values
t.prgsize = prgsize * 16384
t.chrsize = chrsize * 8192
t.wramsize = math.tointeger(2^wramsize*64)
t.bramsize = math.tointeger(2^bramsize*64)
t.chrbramsize = math.tointeger(2^chrbramsize*64)
t.chrramsize = math.tointeger(2^chrramsize*64)
mappers.header=t
end
local n0ne = function(x) return not x or x == 0 end
local val0 = function(x) return x and x or 0 end
--[[
https://wiki.nesdev.com/w/index.php/NROM
4kB chrroms are created, unless t.onechrrom is set, in which case only one big chrrom
location is created instead.
]]
mappers.NROM = function(t)
if not t then t = {} end
if not t.prgsize then t.prgsize = 16384 end
assert(t.prgsize == 16384 or t.prgsize == 32768, "prgsize must be 16 or 32kB")
if n0ne(t.chrsize) and n0ne(t.chrramsize) and n0ne(t.chrbramsize) then t.chrsize = 8192 end
assert(val0(t.chrsize) + val0(t.chrramsize) + val0(t.chrbramsize) == 8192, "combined chrrom size must be 8kB")
assert(not t.mirror or ({ h=1, v=1 })[t.mirror:lower()], "only H and V mirroring are supported")
local prgstart = 0x10000 - t.prgsize
hdrrom = location{prgstart - 16, prgstart - 1, name='header'}
header(t)
prgrom0 = location{prgstart, 0xffff, name='prgrom'}
prgrom = prgrom0
section{"vectors", org=0xfffa} dc.w nmi, main, irq
if (t.chrsize > 0) then
if t.onechrrom then
chrrom0 = location{0x10000, 0x10000 + 0x1fff, name='chrrom'}
else
for ci=0,1 do
local o = 0x10000 + ci*0x1000
_ENV['chrrom'..ci] = location{o, o+0xfff, name='chrrom'..ci}
end
end
chrrom = chrrom0
end
end
mappers[0] = mappers.NROM
--[[
https://wiki.nesdev.com/w/index.php/UxROM
Has bus conflicts.
4kB chrroms are created, unless t.onechrrom is set, in which case only one big chrrom
location is created instead.
]]
mappers.UxROM = function(t)
if not t then t = {} end
t.mapperid = 2
if not t.prgsize then t.prgsize = 32768 end
assert(t.prgsize >= 0x8000 and t.prgsize <= 0x40000, "prgsize must be at least 32kB and at most 256kB")
if not t.chrsize then t.chrsize = 8192 end
assert(t.chrsize == 0x2000, "chrsize must be 8kB")
assert(not t.mirror or ({ h=1, v=1 })[t.mirror:lower()], "only H and V mirroring are supported")
local bc = t.prgsize//0x4000
for bi=0,bc-2 do
local o,ix = 0x8000 + bi*0x4000, bc-1-bi
_ENV['prgrom'..ix] = location{o, o+0x3fff, rorg=0x8000, name='prgrom'..ix}
end
local prglast = 0x8000 + (bc-1)*0x4000
prgrom0 = location{prglast, prglast+0x3fff, rorg=0xc000, name='prgrom0'}
prgrom = prgrom0
section{"vectors", org=prglast+0x3ffa} dc.w nmi, main, irq
@@bankbytes -- for handling bus conflicts
for i=0,bc-2 do byte(i) end
local chrstart = 0x8000 + bc*0x4000
if t.onechrrom then
chrrom0 = location{chrstart, chrstart + 0x1fff, name='chrrom'}
else
for ci=0,1 do
local o = chrstart + ci*0x1000
_ENV['chrrom'..ci] = location{o, o+0xfff, name='chrrom'..ci}
end
end
chrrom = chrrom0
function switchprgrom(bankix)
assert(bankix < bc-1)
lda #bankix tax sta bankbytes,x
end
mappers.init = function()
switchprgrom(1)
end
end
mappers[2] = mappers.UxROM
--[[
https://wiki.nesdev.com/w/index.php/CNROM
Has bus conflicts.
8kB chrroms are created, unless t.onechrrom is set, in which case only one big chrrom
location is created instead.
]]
mappers.CNROM = function(t)
if not t then t = {} end
t.mapperid = 3
if not t.prgsize then t.prgsize = 16384 end
assert(t.prgsize == 16384 or t.prgsize == 32768, "prgsize must be 16 or 32kB")
if not t.chrsize then t.chrsize = 8192 end
assert(t.chrsize >= 0x2000 and t.chrsize <= 0x8000, "chrsize must be at least 8kB and at most 32kB")
assert(not t.mirror or ({ h=1, v=1 })[t.mirror:lower()], "only H and V mirroring are supported")
local prgstart = 0x10000 - t.prgsize
hdrrom = location{prgstart - 16, prgstart - 1, name='header'}
header(t)
prgrom = location{prgstart, 0xffff, name='prgrom'}
section{"vectors", org=0xfffa} dc.w nmi, main, irq
@@bankbytes -- for handling bus conflicts
dc.b 0x00, 0x01, 0x02, 0x03
dc.b 0x10, 0x11, 0x12, 0x13
dc.b 0x20, 0x21, 0x22, 0x23
dc.b 0x30, 0x31, 0x32, 0x33
local cc = t.chrsize//0x2000
if t.onechrrom then
chrrom0 = location{chrstart, chrstart + cc*0x2000 - 1, rorg=0, name='chrrom'}
else
for ci=0,cc-1 do
local o = chrstart + ci*0x2000
_ENV['chrrom'..ci] = location{o, o+0x2000-1, rorg=0, name='chrrom'..ci}
end
end
chrrom = chrrom0
securitydiodes = 0 -- set to actual value, eg 0x20
function switchchrrom(bankix)
assert(bankix < cc)
assert(securitydiodes < 0x40)
ldx #bankix|securitydiodes>>2 lda #bankix|securitydiodes sta bankbytes,x
end
mappers.init = function()
switchchrrom(0)
end
end
mappers[3] = mappers.CNROM
--[[
https://wiki.nesdev.com/w/index.php/GxROM
Has bus conflicts.
prgroms are numbered from last (0) to first (#-1), so that adding more does not change
prgrom0, which must contain the reset vector (main).
8kB chrroms are created, unless t.onechrrom is set, in which case only one big chrrom
location is created instead.
]]
mappers.GxROM = function(t)
if not t then t = {} end
t.mapperid = 66
if not t.prgsize then t.prgsize = 32768 end
assert(t.prgsize >= 0x8000 and t.prgsize <= 0x20000, "prgsize must be at least 32kB and at most 128kB")
if not t.chrsize then t.chrsize = 8192 end
assert(t.chrsize >= 0x2000 and t.chrsize <= 0x8000, "chrsize must be at least 8kB and at most 32kB")
assert(not t.mirror or ({ h=1, v=1 })[t.mirror:lower()], "only H and V mirroring are supported")
hdrrom = location{0x7ff0, 0x7fff, name='header'}
header(t)
local bc = t.prgsize//0x8000
for bi=0,bc-1 do
local o,ix = 0x8000 + bi*0x8000, bc-1-bi
_ENV['prgrom'..ix] = location{o, o+0x7fff, rorg=0x8000, name='prgrom'..ix}
section("bankbytes"..ix) -- for handling bus conflicts
dc.b 0x00, 0x01, 0x02, 0x03
dc.b 0x10, 0x11, 0x12, 0x13
dc.b 0x20, 0x21, 0x22, 0x23
dc.b 0x30, 0x31, 0x32, 0x33
end
section{"vectors", org=0x8000+bc*0x8000-6} dc.w nmi, main, irq
prgrom = prgrom0
local cc = t.chrsize//0x2000
if t.onechrrom then
chrrom0 = location{chrstart, chrstart + cc*0x2000 - 1, rorg=0, name='chrrom'}
else
for ci=0,cc-1 do
local o = chrstart + ci*0x2000
_ENV['chrrom'..ci] = location{o, o+0x2000-1, rorg=0, name='chrrom'..ci}
end
end
chrrom = chrrom0
bankregister = 0
function switchprgrom(bankix)
assert(bankix < bc)
bankregister = (bankregister & ~0x30) | (bankix << 4)
ldx #bankregister&3|bankregister>>2 lda #bankregister sta bankbytes0,x
end
function switchchrrom(bankix)
assert(bankix < cc)
bankregister = (bankregister & ~3) | bankix
ldx #bankregister&3|bankregister>>2 lda #bankregister sta bankbytes0,x
end
mappers.init = function()
switchchrrom(0)
end
end
mappers[66] = mappers.GxROM
--[[
https://wiki.nesdev.com/w/index.php/MMC1
prgroms are numbered from last (0) to first (#-1), so that adding more does not change
prgrom0, which must contain the reset vector (main).
t.prgmap is an optional function taking a prgrom bank index and returning its rorg value.
Default is to create 16kB banks if prgswitchmode is not all, 32kB otherwise, and rorg them
accordingly.
Same goes for chrrom sizes.
If t.onechrrom is set, only one big chrrom location is created instead.
t.prgswitchmode:
'first' makes 0x8000-0xbfff switchable (default)
'last' makes 0xc000-0xffff switchable
'all' makes 0x8000-0xffff switchable
t.chrswitchmode:
'all' switches whole 8kB at a time (default)
'half' switches 2 separate 4kB banks
]]
mappers.MMC1 = function(t)
if not t then t = {} end
t.mapperid = 1
if not t.prgswitchmode then t.prgswitchmode = 'first' end
if not t.chrswitchmode then t.chrswitchmode = 'all' end
if not t.wramsize then t.wramsize = 0 end
if not t.bramsize and t.wramsize == 0 then t.bramsize = 8192 end
local prgram = t.bramsize + t.wramsize
assert(prgram >= 0x2000 and prgram <= 0x8000, "bramsize or wramsize must be at least 8kB and at most 32kB")
if not t.prgsize then t.prgsize = 32768 end
assert(t.prgsize >= 0x8000 and t.prgsize <= 0x80000, "prgsize must be at least 32kB and at most 512kB")
if not t.chrsize then t.chrsize = 8192 end
assert(t.chrsize >= 0x2000 and t.chrsize <= 0x20000, "chrsize must be at least 8kB and at most 128kB")
hdrrom = location{0x7FF0, 0x7FFF, name='header'}
header(t)
local bsz = t.prgswitchmode=='all' and 0x8000 or 0x4000
local prgmap = t.prgmap or function(bi, bc) return t.prgswitchmode=='last' and 0xc000 or 0x8000 end
local bc = t.prgsize//bsz
for bi=0,bc-1 do
local o,ix = 0x8000 + bi*bsz, bc-1-bi
_ENV['prgrom'..ix] = location{o, o+bsz-1, rorg=prgmap(ix,bc), name='prgrom'..ix}
end
section{"vectors", org=0x8000+bc*bsz-6} dc.w nmi, main, irq
prgrom = prgrom0
local chrstart = 0x8000 + bc*bsz
local csz = t.chrswitchmode=='all' and 0x2000 or 0x1000
local cc = t.chrsize//csz
local chrmap = t.chrmap or function(ci, cc) if csz==0x2000 then return 0 else return (ci&1)*csz end end
if t.onechrrom then
chrrom0 = location{chrstart, chrstart + cc*csz - 1, rorg=0, name='chrrom'}
else
for ci=0,cc-1 do
local o = chrstart + ci*csz
_ENV['chrrom'..ci] = location{o, o+csz-1, rorg=chrmap(ci,cc), name='chrrom'..ci}
end
end
chrrom = chrrom0
local prgswitchmodemap = { all=0, first=3<<2, last=2<<2 }
local chrswitchmodemap = { all=0, half=1<<4 }
mmc1ctrl = (mappers.header.mirror==1 and 2 or 3) | prgswitchmodemap[t.prgswitchmode] | chrswitchmodemap[t.chrswitchmode]
function mmc1write(reg)
sta reg lsr sta reg lsr sta reg lsr sta reg lsr sta reg
end
-- Can be turned into a function, A must contain the bank index.
-- eg:
-- @@switchprgrom_func switchprgrom_f()
-- switchprgrom_f = function() jsr switchprgrom_func rts end
function switchprgrom_f() mmc1write(0xe000) end
function switchprgrom(bankix)
assert(bankix < t.prgsize//0x4000)
lda #bankix
switchprgrom_f()
end
function switchchrrom_f(slot) assert(slot<2) mmc1write(slot==0 and 0xa000 or 0xc000) end
function switchchrrom(bankix, slot)
assert(bankix < t.chrsize//0x1000)
lda #bankix
switchchrrom_f(slot or 0)
end
function setmirror(mirror)
mirror = assert(({ h=3, v=2, hi=1, lo=0 })[mirror:lower()])
mmc1ctrl = (mmc1ctrl & ~3) | mirror
lda #mmc1ctrl mmc1write(0x8000)
end
function setprgswitchmode(mode)
mode = assert(prgswitchmodemap[mode])
mmc1ctrl = (mmc1ctrl & ~0xc) | mode
lda #mmc1ctrl mmc1write(0x8000)
end
function setchrswitchmode(mode)
mode = assert(chrswitchmodemap[mode])
mmc1ctrl = (mmc1ctrl & ~0x10) | mode
lda #mmc1ctrl mmc1write(0x8000)
end
mappers.init = function()
lda #0x80 sta 0x8000
lda #mmc1ctrl mmc1write(0x8000)
if t.prgswitchmode ~= 'all' then switchprgrom(1) end
switchchrrom(0) if t.chrswitchmode ~= 'all' then switchchrrom(1,1) end
end
end
mappers[1] = mappers.MMC1
--[[
https://wiki.nesdev.com/w/index.php/MMC3
prgroms are numbered from last (0) to first (#-1), so that adding more does not change
prgrom0, which must contain the reset vector (main).
Last 2 prg banks are merged into 1 16kB bank, to allow linker optimization - hence, 0 must
always be set on bit 6 of bank select, even; also, there is no prgrom1 as a consequence.
t.prgmap is an optional function taking a prgrom bank index and returning its rorg value.
Default is to map even banks to 0x8000, and odd to 0xa000.
chrroms are all 1kB, so they can work with chr A12 inversion enabled or not.
If t.onechrrom is set, only one big chrrom location is created instead.
With default submapper id of 0, this defaults to revision MM3C, which generates a scanline
interrupt at each scanline when counter is loaded with 0.
]]
mappers.MMC3 = function(t)
if not t then t = {} end
t.mapperid = 4
if not t.bramsize then t.bramsize = 8192 end
assert(t.bramsize == 8192, "bramsize must be 8kB")
if not t.prgsize then t.prgsize = 32768 end
assert(t.prgsize >= 0x8000 and t.prgsize <= 0x80000, "prgsize must be at least 32kB and at most 512kB")
if not t.chrsize then t.chrsize = 8192 end
assert(t.chrsize >= 0x2000 and t.chrsize <= 0x40000, "chrsize must be at least 8kB and at most 256kB")
hdrrom = location{0x7FF0, 0x7FFF, name='header'}
header(t)
local prgmap = t.prgmap or function(bi, bc) return 0x8000+(bi&1)*0x2000 end
local bc = t.prgsize//0x2000
for bi=0,bc-3 do
local o,ix = 0x8000 + bi*0x2000, bc-bi-1
_ENV['prgrom'..ix] = location{o, o+0x1fff, rorg=prgmap(ix,bc), name='prgrom'..ix}
end
do
local o = 0x8000 + (bc-2)*0x2000
prgrom0 = location{o, o+0x3fff, rorg=0xc000, name='prgrom0'}
section{"vectors", org=o+0x3ffa} dc.w nmi, main, irq
end
prgrom = prgrom0
local chrmap = t.chrmap or function(ci, cc) return (ci&7)*0x400 end
local chrstart = 0x8000 + bc*0x2000
local cc = t.chrsize//0x400
if t.onechrrom then
chrrom0 = location{chrstart, chrstart + cc*0x400 - 1, rorg=0, name='chrrom'}
else
for ci=0,cc-1 do
local o = chrstart + ci*0x400
_ENV['chrrom'..ci] = location{o, o+0x3ff, rorg=chrmap(ci,cc), name='chrrom'..ci}
end
end
chrrom = chrrom0
local a12inv = false
function seta12inv(enabled) a12inv = enabled end
function switchprgrom(bankix, slot)
assert(slot<2)
slot = slot + 6
if a12inv then slot = slot | 0x80 end
lda #slot sta 0x8000
assert(bankix < bc)
bankix = bc-1-bankix -- reverse index order, since we set 0 as last
lda #bankix sta 0x8001
end
-- slot [0, 7], each slot is 1kB counting in order, regardless of a12inv state
function switchchrrom(bankix, slot)
assert(slot<8)
if a12inv then
assert(slot ~= 5 and slot ~= 7)
if slot == 6 then slot = 1
elseif slot == 4 then slot = 0
else slot = slot + 2 end
slot = slot | 0x80
else
assert(slot ~= 1 and slot ~= 3)
if slot == 2 then slot = 1
elseif slot > 3 then slot = slot - 2 end
end
lda #slot sta 0x8000
assert(bankix < cc)
lda #bankix sta 0x8001
end
function setmirror(mirror)
mirror = assert(({ h=1, v=0 })[mirror:lower()])
lda #mirror sta 0xa000
end
function protectsram() lda 0x40 sta 0xa001 end
function scanlineirq(count) ldx #1 stx 0xe000 lda #count-1 sta 0xc000 sta 0xc001 stx 0xe001 end
mappers.init = function()
switchprgrom(2, 0) switchprgrom(3, 1)
switchchrrom(0, 0) switchchrrom(2, 2)
switchchrrom(4, 4) switchchrrom(5, 5) switchchrrom(6, 6) switchchrrom(7, 7)
local mirror = mappers.header.mirror
if mirror==0 or mirror==1 then lda #mirror~1 sta 0xa000 end
lda #0x80 sta 0xa001
end
end
mappers[4] = mappers.MMC3
--[[
https://wiki.nesdev.com/w/index.php/MMC5
https://forums.nesdev.com/viewtopic.php?f=9&t=16789
main MUST be in 0xe000-0xfff9 of last prgrom.
prgroms are numbered from last (0) to first (#-1), so that adding more does not change
prgrom0, which must contain the reset vector (main).
t.prgmap is an optional function taking a prgrom bank index and returning its rorg value.
Default is to map banks in sequence to 0x8000, 0xa000, 0xc000, and 0xe000.
chrroms are all 1kB. Provide t.chrmap if needed, same as t.prgmap.
If t.onechrrom is set, only one big chrrom location is created instead.
]]
mappers.MMC5 = function(t)
if not t then t = {} end
t.mapperid = 5
assert(val0(t.bramsize) + val0(t.wramsize) <= 0x10000, "bramsize + wramsize must be at most 64kB")
if not t.prgsize then t.prgsize = 8192 end
assert(t.prgsize <= 0x100000, "prgsize must be at most 1MB")
if not t.chrsize then t.chrsize = 8192 end
assert(t.chrsize <= 0x100000, "chrsize must be at most 1MB")
hdrrom = location{0x7FF0, 0x7FFF, name='header'}
header(t)
local prgmap = t.prgmap or function(bi, bc) return 0x8000+(bi&3)*0x2000 end
local bc = t.prgsize//0x2000
for bi=0,bc-2 do
local o,ix = 0x8000 + bi*0x2000, bc-bi-1
_ENV['prgrom'..ix] = location{o, o+0x1fff, rorg=prgmap(ix,bc), name='prgrom'..ix}
end
do
local o = 0x8000 + (bc-1)*0x2000
prgrom0 = location{o, o+0x1fff, rorg=0xe000, name='prgrom0'}
section{"vectors", org=o+0x1ffa} dc.w nmi, main, irq
section{"main", org=o} -- enforce entry point in last bank
end
prgrom = prgrom0
local chrmap = t.chrmap or function(ci, cc) return (ci&7)*0x400 end
local chrstart = 0x8000 + bc*0x2000
local cc = t.chrsize//0x400
if t.onechrrom then
chrrom0 = location{chrstart, chrstart + cc*0x400 - 1, rorg=0, name='chrrom'}
else
for ci=0,cc-1 do
local o = chrstart + ci*0x400
_ENV['chrrom'..ci] = location{o, o+0x3ff, rorg=chrmap(ci,cc), name='chrrom'..ci}
end
end
chrrom = chrrom0
function prgbankmode(mode) if mode then lda #mode end sta 0x5100 end
function chrbankmode(mode) if mode then lda #mode end sta 0x5101 end
function wrammode(mode) if mode then lda #mode end sta 0x5104 end
function protectsram() lda #0 sta 0x5102 sta 0x5103 end
function screenmap(map) if map then lda #map end sta 0x5105 end
function filltile(tile) if tile then lda #tile end sta 0x5106 end
function fillcolor(col) if col then lda #col end sta 0x5107 end
function switchprgram(chip, bank)
assert(chip == 0 or chip == 1)
assert(bank < 4)
lda #chip<<2|bank sta 0x5113
end
function switchprgrom0(bank, isram) lda #bank|(isram and 0 or 0x80) sta 0x5114 end
function switchprgrom1(bank, isram) lda #bank|(isram and 0 or 0x80) sta 0x5115 end
function switchprgrom2(bank, isram) lda #bank|(isram and 0 or 0x80) sta 0x5116 end
function switchprgrom3(bank, isram) lda #bank|(isram and 0 or 0x80) sta 0x5117 end
function switchchrrom(bank, slot) -- 1kB mode
assert(slot < 12)
assert(bank < cc)
lda #bank>>7 sta 0x5130
lda #bank sta slot+0x5120
end
vsplitmode = 0
function vsplitstart(starttile)
assert(starttile < 32)
vsplitmode = (vsplitmode & ~31) | starttile
lda #vsplitmode sta 0x5200
end
function vsplitside(side)
assert(side == 'left' or side == 'right')
vsplitmode = (vsplitmode & ~0x40) | (side == 'right' and 1 or 0)
lda #vsplitmode sta 0x5200
end
function vsplitenable(enabled)
vsplitmode = (vsplitmode & ~0x80) | (enabled and 1 or 0)
lda #vsplitmode sta 0x5200
end
function vsplitscroll(vscroll) if vscroll then lda #vscroll end sta 0x5201 end
function vsplitbank(chrbank) if chrbank then lda #chrbank end sta 0x5202 end
function scanlineirq(atscanline) lda #0 sta 0x5204 lda #atscanline sta 0x5203 lda #0x80 sta 0x5204 end
function irqenable(enabled) lda #enabled and 0x80 or 0 sta 0x5204 end
-- 0x40 set: PPU is rendering visible scanlines
-- 0x80 set: a scanlineirq is pending (internal counter reach atscanline value set with scanlineirq())
function irqstatus() lda 0x5204 end
-- multiplies a*x = x:a (x hi, a lo)
function mul() sta 0x5205 stx 0x5206 lda 0x5205 ldx 0x5206 end
mappers.init = function()
ldx #2 stx 0x5102 dex stx 0x5103
lda #vsplitmode sta 0x5200
prgbankmode(2)
switchprgrom1(3) -- map prg rom 3, 2, x, 0
switchprgrom2(1) -- map prg rom 3, 2, 1, 0
chrbankmode(0) switchchrrom(0, 7) chrbankmode(3) -- map chr rom 0 to the 8kB, and set mode to 1kB slices
end
end
mappers[5] = mappers.MMC5
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