Sections now generate regular labels for themselves.

6502.lua

@@ -2,6 +2,7 @@ local M = {}
 
 local symbols={} M.symbols=symbols
 local locations={} M.locations=locations
+local sections={} M.sections=sections
 local stats={} M.stats=stats setmetatable(stats, stats)
 
 M.strip = true  -- set to false to disable dead stripping of relocatable sections
@@ -22,6 +23,9 @@ end
 symbols.__index = symbols
 setmetatable(M, symbols)
 
+local id_ = 0
+local id = function() id_=id_+1 return id_ end M.id=id
+
 M.link = function()
     if stats.unused then return end
 
@@ -34,79 +38,28 @@ M.link = function()
             return val
         end
     end
-    for _,location in ipairs(locations) do
+    for _,section in ipairs(sections) do
-        for _,section in ipairs(location.sections) do
         section:compute_size()
     end
-    end
     symbols.__index = symbols
 
-    stats.used = 0
+    local chunk_reserve = function(chunks, chunk_ix, chunk, start, size)
-    stats.unused = 0
-    stats.cycles = 0
-    for _,location in ipairs(locations) do
-        local sections,rorg = location.sections,location.rorg
-
-        local chunk_reserve = function(chunk_ix, chunk, start, size)
         if start == chunk.start then
-                if size == chunk.size then location.chunks[chunk_ix] = nil
+            if size == chunk.size then chunks[chunk_ix] = nil
             else chunk.start=start+size chunk.size=chunk.size-size end
         else
             if chunk.size - (start - chunk.start) == size then chunk.size = chunk.size - size
             else
                 local sz = start - chunk.start
-                    table.insert(location.chunks, chunk_ix+1, { start=start+size, size=chunk.size-(sz+size) })
+                table.insert(chunks, chunk_ix+1, { start=start+size, size=chunk.size-(sz+size) })
                 chunk.size = sz
             end
         end
     end
 
-        -- filter sections list
+    local position_section = function(section, constrain)
-        local position_independent_sections = {}
+        local location = section.location
-        local symbols_to_remove = {}
+        local rorg = location.rorg
-        local section_count = #sections
-        location.cycles=0 location.used=0
-        for ix,section in ipairs(sections) do
-            location.cycles = location.cycles + section.cycles
-            location.used = location.used + section.size
-            if section.size == 0 then
-                sections[ix]=nil
-                if not section.org then table.insert(symbols_to_remove, section.label) end
-            elseif not section.org then
-                if M.strip and not section.refcount and not section.strong then 
-                    sections[ix]=nil
-                    table.insert(symbols_to_remove, section.label)
-                else
-                    table.insert(position_independent_sections, section)
-                end
-            end
-        end
-        do local j=0 for i=1,section_count do
-            if sections[i] ~= nil then j=j+1 sections[j],sections[i] = sections[i],sections[j] end
-        end end
-        for _,v in ipairs(symbols_to_remove) do symbols[v] = nil end
-        stats.cycles = stats.cycles + location.cycles
-        stats.used = stats.used + location.used
-
-        -- fixed position sections
-        for section_ix,section in ipairs(sections) do if section.org then
-            if section.org < location.start or section.org > location.finish then
-                error("ORG section " .. section.label .. " starts outside container location")
-            end
-            for chunk_ix,chunk in ipairs(location.chunks) do
-                if chunk.start <= section.org and chunk.size - (section.org - chunk.start) >= section.size then
-                    chunk_reserve(chunk_ix, chunk, section.org, section.size)
-                    symbols[section.label] = rorg(section.org)
-                    goto chunk_located
-                end
-            end
-            error("ORG section " .. section.label .. " overflows its location")
-            ::chunk_located::
-        end end
-
-        -- position independent sections
-        table.sort(position_independent_sections, function(a,b) return a.size==b.size and a.label>b.label or a.size>b.size end)
-        for _,section in ipairs(position_independent_sections) do
         local chunks = {}
         for _,chunk in ipairs(location.chunks) do
             if chunk.size >= section.size then chunks[#chunks+1] = chunk end
@@ -155,6 +108,7 @@ M.link = function()
                         if lsb_cur <= lsb_new then goto constraints_not_met end
                     end
                     ::select_pos::
+                    if constrain and not constrain(address) then goto constraints_not_met end
                     waste=w position=address position_end=address_end
                     ::constraints_not_met::
                 end
@@ -166,16 +120,94 @@ M.link = function()
                 usage_lowest(start, chunk.start + chunk.size - section.size)
             end
             if position then
-                    chunk_reserve(chunk_ix, chunk, position, section.size)
+                chunk_reserve(location.chunks, chunk_ix, chunk, position, section.size)
                 section.org = position
                 symbols[section.label] = rorg(position)
                 --print(section.label, string.format("%04X\t%d", position, section.size))
                 --for k,v in ipairs(location.chunks) do print(string.format("  %04X  %04X  %d", v.start, v.size+v.start-1, v.size)) end
+                return position
+            end
+        end
+    end
+
+    local sibling_sections = {}
+    stats.used = 0
+    stats.unused = 0
+    stats.cycles = 0
+    for _,location in ipairs(locations) do
+        local sections,rorg = location.sections,location.rorg
+
+        -- filter sections list
+        local position_independent_sections = {}
+        local symbols_to_remove = {}
+        local section_count = #sections
+        location.cycles=0 location.used=0
+        for ix,section in ipairs(sections) do
+            location.cycles = location.cycles + section.cycles
+            location.used = location.used + section.size
+            if section.size == 0 then
+                sections[ix]=nil
+                if not section.org then table.insert(symbols_to_remove, section.label) end
+            elseif not section.org then
+                if M.strip and not section.refcount and not section.strong then 
+                    sections[ix]=nil
+                    table.insert(symbols_to_remove, section.label)
+                elseif section.siblings then
+                    table.insert(sibling_sections, section)
+                else
+                    table.insert(position_independent_sections, section)
+                end
+            end
+        end
+        do local j=0 for i=1,section_count do
+            if sections[i] ~= nil then j=j+1 sections[j],sections[i] = sections[i],sections[j] end
+        end end
+        for _,v in ipairs(symbols_to_remove) do symbols[v] = nil end
+        location.position_independent_sections = position_independent_sections
+        stats.cycles = stats.cycles + location.cycles
+        stats.used = stats.used + location.used
+
+        -- fixed position sections
+        for section_ix,section in ipairs(sections) do if section.org then
+            if section.org < location.start or section.org > location.finish then
+                error("ORG section " .. section.label .. " starts outside container location")
+            end
+            for chunk_ix,chunk in ipairs(location.chunks) do
+                if chunk.start <= section.org and chunk.size - (section.org - chunk.start) >= section.size then
+                    chunk_reserve(location.chunks, chunk_ix, chunk, section.org, section.size)
+                    symbols[section.label] = rorg(section.org)
                     goto chunk_located
                 end
             end
-            error("unable to find space for section " .. section.label)
+            error("ORG section " .. section.label .. " overflows its location")
             ::chunk_located::
+        end end
+    end
+--[[
+    for _,section in ipairs(sibling_sections) do
+        local sections = section.siblings
+        table.insert(sections, section)
+        -- biggest of all siblings first
+        table.sort(sections, function(a,b) return a.size==b.size and a.id<b.id or a.size>b.size end)
+    end
+    table.sort(sibling_sections, function(a,b) return a[1].size==b[1].size and a[1].id<b[1].id or a[1].size>b[1].size end)
+    for _,section in ipairs(sibling_sections) do
+        local siblings = section.siblings
+        local relate = section.relate or function(sibling, siblings)
+        end
+        for _,sibling in siblings do
+            if not relate(sibling, siblings) then goto not_suitable end
+        end
+        ::not_suitable::
+    end
+]]
+    for _,location in ipairs(locations) do
+        local position_independent_sections = location.position_independent_sections
+        table.sort(position_independent_sections, function(a,b) return a.size==b.size and a.label>b.label or a.size>b.size end)
+        for _,section in ipairs(position_independent_sections) do
+            if not position_section(section) then
+                error("unable to find space for section " .. section.label)
+            end
         end
 
         -- unused space stats
@@ -235,7 +267,6 @@ M.genbin = function(filler)
         for _,section in ipairs(sections) do
             assert(section.org >= #bin+of0)
             for i=#bin+of0,section.org-1 do ins(bin, filler) end
-            M.label_current = section.label
             for _,instruction in ipairs(section.instructions) do
                 local b,f = instruction.bin,instruction.asbin
                 if b then mov(b,1,#b,#bin+1,bin)
@@ -323,7 +354,7 @@ M.location = function(start, finish)
             location.rorg = function(x) return x+offset end
         end
     end
-    location.sections = {}
+    location.sections = {} -- TODO remove
     if not location.rorg then location.rorg = function(x) return x end end
     local size = (location.finish or math.huge) - location.start + 1
     location.chunks={ { start=location.start, size=size } }
@@ -334,21 +365,22 @@ end
 
 M.section = function(t)
     local section = {}
-    if (type(t) == 'string') then section.label = t
+    local name = t or 'S'..id()
-    else
+    if (type(name) ~= 'string') then
-        assert(type(t) == 'table')
+        assert(type(t) == 'table', "invalid arguments for section")
-        assert(type(t[1]) == 'string' and string.len(t[1]) > 0)
+        assert(type(t[1]) == 'string' and string.len(t[1]) > 0, "invalid name for section")
-        section=t section.label=t[1] section[1]=nil
+        section=t name=t[1] section[1]=nil
-        if section.offset and not section.align then error("section " .. section.label .. " has offset, but no align") end
+        if section.offset and not section.align then error("section " .. name .. " has offset, but no align") end
     end
-    table.insert(M.location_current.sections, section)
+    table.insert(M.location_current.sections, section) -- TODO remove
-    if symbols[section.label] then error("duplicate symbol: " .. section.label) end
+    table.insert(M.sections, section)
-    symbols[section.label] = section
+    section.location = M.location_current
-    M.label_current = section.label
     M.section_current = section
-    section.type = 'section'
+    section.id = id()
     section.constraints = {}
     section.instructions = {}
+    assert(name:sub(1,1) ~= '_', "sections can't be named with a local label")
+    section.label = M.label(name)
     function section:compute_size()
         local instructions = self.instructions
         self.size=0 self.cycles=0
@@ -373,12 +405,11 @@ M.section = function(t)
     return section
 end
 
-M.label_gen_ix = 0
 M.label = function(name)
     local label,offset
     local section,rorg = M.section_current,M.location_current.rorg
-    label = { type='label' }
+    label = { type='label', section=section }
-    if not name then name='_L'..M.label_gen_ix M.label_gen_ix=M.label_gen_ix+1 end
+    if not name then name='_L'..id() end
     if name:sub(1,1) == '_' then -- local label
         name = M.label_current .. name
     else
@@ -412,9 +443,18 @@ M.endpage = function()
     constraint.to = #section.instructions
 end
 
+M.sleep = function(cycles, noillegal)
+    assert(cycles > 1, "can't sleep for less than 2 cycles")
+    if cycles & 1 ~= 0 then
+        if noillegal then bitzpg(0) else nopzpg(0) end
+        cycles = cycles - 3
+    end
+    for i=1,cycles/2 do nopimp() end
+end
+
 local size_ref = function(v)
     if type(v) == 'string' then v=symbols[v] end
-    if type(v) == 'table' and v.type == 'section' then v.refcount = 1 + (v.refcount or 0) end
+    if type(v) == 'table' and v.type == 'label' then v.section.refcount = 1 + (v.section.refcount or 0) end
 end
 local size_dc = function(v)
     if type(v) == 'function' then

samples/vcs0.l65

@@ -0,0 +1,15 @@
+require'vcs'
+mappers['2K']()
+
+local kernel = function()
+    ldx#0xb0 @_loop sta WSYNC stx COLUBK dex bne _loop
+end
+
+@@main
+    init()
+@_frame
+    overscan() vblank() screen(kernel) jmp _frame
+
+writebin(filename..'.bin')
+writesym(filename..'.sym')
+print(stats)

vcs.l65

@@ -84,45 +84,160 @@ do
     for k,v in pairs(vcs) do symbols[k] = v end
 end
 
+NTSC = {
+    TIM_OVERSCAN    = 38, -- TIM64T,  2432 cycles =   32 scanlines
+    TIM_VBLANK      = 45, -- TIM64T,  2880 cycles = ~ 38 scanlines
+    TIM_KERNEL      = 15, -- T1024T, 15360 cycles = ~202 scanlines
+}
+PAL = {
+    TIM_OVERSCAN    = 50, -- TIM64T,  3200 cycles = ~ 42 scanlines
+    TIM_VBLANK      = 61, -- TIM64T,  3904 cycles = ~ 51 scanlines
+    TIM_KERNEL      = 17, -- T1024T, 17408 cycles = ~229 scanlines
+}
+TV = PAL
+
+init = function() cld ldx#0 txa local l=label() dex tsx pha bne l end
+wait = function() local l=label() lda INTIM bne l end
+overscan_begin = function() sta WSYNC lda#2 sta VBLANK lda#TV.TIM_OVERSCAN sta TIM64T end
+overscan_end = wait
+overscan = function(f) overscan_begin() if f then f() end overscan_end() end
+vblank_begin = function()
+    lda#0b1110 local l=label() sta WSYNC sta VSYNC lsr bne l
+    lda#2 sta VBLANK lda#TV.TIM_VBLANK sta TIM64T
+end
+vblank_end = function() wait() sta WSYNC sta VBLANK end
+vblank = function(f) vblank_begin() if f then f() end vblank_end() end
+screen_begin = function() lda#TV.TIM_KERNEL sta T1024T end
+screen_end = wait
+screen = function(f) screen_begin() if f then f() end screen_end() end
+
+nusiz = {
+    MSL_SIZE_1 = 16*0,
+    MSL_SIZE_2 = 16*1,
+    MSL_SIZE_4 = 16*2,
+    MSL_SIZE_8 = 16*3,
+    ONE_COPY = 0,
+    TWO_COPIES_CLOSE = 1,
+    TWO_COPIES_MEDIUM = 2,
+    THREE_COPIES_CLOSE = 3,
+    TWO_COPIES_WIDE = 4,
+    DOUBLE_SIZED_PLAYER = 5,
+    THREE_COPIES_MEDIUM = 6,
+    QUAD_SIZED_PLAYER = 7,
+}
+
+ctrlpf = {
+	BALL_SIZE_1 = 16*0,
+	BALL_SIZE_2 = 16*1,
+	BALL_SIZE_4 = 16*2,
+	BALL_SIZE_8 = 16*3,
+	PF_MIRRORED = 1,
+	PF_SCOREMODE = 2,
+	PF_PRIO_BALLABOVE = 4,
+}
+
+enable = {
+	DISABLE = 0,
+	ENABLE = 2,
+}
+
+vdel = {
+	DISABLE = 0,
+	ENABLE = 1,
+}
+
+hm = {
+	LEFT_7 = 7*16,
+	LEFT_6 = 6*16,
+	LEFT_5 = 5*16,
+	LEFT_4 = 4*16,
+	LEFT_3 = 3*16,
+	LEFT_2 = 2*16,
+	LEFT_1 = 1*16,
+	NO_MOTION = 0,
+	RIGHT_1 = 15*16,
+	RIGHT_2 = 14*16,
+	RIGHT_3 = 13*16,
+	RIGHT_4 = 12*16,
+	RIGHT_5 = 11*16,
+	RIGHT_6 = 10*16,
+	RIGHT_7 = 9*16,
+	RIGHT_8 = 8*16,
+	
+	C74_LEFT_15 = 7*16,
+	C74_LEFT_14 = 6*16,
+	C74_LEFT_13 = 5*16,
+	C74_LEFT_12 = 4*16,
+	C74_LEFT_11 = 3*16,
+	C74_LEFT_10 = 2*16,
+	C74_LEFT_9 = 1*16,
+	C74_LEFT_8 = 0*16,
+	C74_LEFT_7 = 15*16,
+	C74_LEFT_6 = 14*16,
+	C74_LEFT_5 = 13*16,
+	C74_LEFT_4 = 12*16,
+	C74_LEFT_3 = 11*16,
+	C74_LEFT_2 = 10*16,
+	C74_LEFT_1 = 9*16,
+	C74_NO_MOTION = 8*16,
+}
+
+-- for mappers that swap banks in place
+-- call an asm function into another bank and generate the stubs if needed
+local far_stubs = {} M.far_stubs=far_stubs
+local far = function(dst)
+    local stub,loc_src,loc_dst = far_stubs[dst],location_current,dst.section.location
+    if not (stub and stub.stub_caller.location==loc_src and stub.stub_callee.location==loc_dst) then
+        local seccur = section_current
+        local stub_caller = section()   switchrom(loc_dst.rom) skip(6) rts
+        location(loc_dst)
+        local stub_callee = section()   jsr dst switchrom(loc_src.rom)
+        location(loc_src) section_current=seccur
+        far_stubs[dst] = relate(stub_caller, stub_callee, 3)
+    end
+    jsr stub_caller
+end
+
 mappers = {}
 
-mappers['2K'] = function()
+mappers['2K'] = function(irq)
     rom0 = location(0xf800, 0xffff)
-    section{"vectors", org=0xfffc} word(main,main)
+    section{"vectors", org=0xfffc} dc.w main if irq then dc.w main end
 end
 mappers.CV = mappers['2K']
 
-mappers['4K'] = function()
+mappers['4K'] = function(irq)
     rom0 = location(0xf000, 0xffff)
-    section{"vectors", org=0xfffc} word(main,main)
+    section{"vectors", org=0xfffc} dc.w main if irq then dc.w main end
 end
 
-local bank_stubs = function(count, hotspot, entry)
+local bank_stubs = function(irq, count, hotspot, entry)
     function switchrom(i) assert(i>=0 and i<count) bit 0x1000+hotspot+i end
+    far = far
     local base = 0x10000 - (count << 12)
     for bi=0,count-1 do
         local o = base+(bi<<12)
-        _ENV['rom' .. bi] = location{o, o+0xfff, rorg=0xf000}
+        _ENV['rom' .. bi] = location{o, o+0xfff, rorg=0xf000, rom=bi}
         local start=section{"entry"..bi, org=o+(entry or hotspot-6)} switchrom(0) if bi==0 then jmp main end
         section{"switchtab"..bi, org=o+hotspot} for i=1,count do byte(0) end
-        section{"vectors"..bi, org=o+0xffc} word(start,start)
+        section{"vectors"..bi, org=o+0xffc} dc.w start if irq then dc.w start end
     end
 end
-mappers.FA = function() bank_stubs(3, 0xff8) end
+mappers.FA = function(irq) bank_stubs(irq, 3, 0xff8) end
-mappers.F8 = function() bank_stubs(2, 0xff8) end
+mappers.F8 = function(irq) bank_stubs(irq, 2, 0xff8) end
-mappers.F6 = function() bank_stubs(4, 0xff6) end
+mappers.F6 = function(irq) bank_stubs(irq, 4, 0xff6) end
-mappers.F4 = function() bank_stubs(8, 0xff4) end
+mappers.F4 = function(irq) bank_stubs(irq, 8, 0xff4) end
-mappers.EF = function() bank_stubs(16, 0xfe0, 0xffc-6) end
+mappers.EF = function(irq) bank_stubs(irq, 16, 0xfe0, 0xffc-6) end
 
-mappers.FE = function()
+mappers.FE = function(irq)
-    rom0 = location(0xd000, 0xdfff)
+    rom1 = location(0xd000, 0xdfff)
-    section{"vectors0", org=0xdffc} word(main,main)
+    section{"vectors1", org=0xdffc} dc.w main if irq then dc.w main end
     location{0xe000, 0xefff, nofill=true}
-    rom1 = location(0xf000, 0xffff)
+    rom0 = location(0xf000, 0xffff)
-    section{"vectors1", org=0xfffc} word(main,main)
+    section{"vectors0", org=0xfffc} dc.w main if irq then dc.w main end
 end
 
-mappers.E0 = function(map)
+mappers.E0 = function(map, irq)
     function switchrom0(i) assert(map[i]==0) bit 0x1fe0+i end
     function switchrom1(i) assert(map[i]==1) bit 0x1fe8+i end
     function switchrom2(i) assert(map[i]==2) bit 0x1ff0+i end
@@ -132,12 +247,12 @@ mappers.E0 = function(map)
         _ENV["rom"..bi] = location{0xe000+o, 0xe3ff+o, rorg=0xf000+map[bi]*0x400}
     end
     section{"switchtab", org=0xffe0} for i=1,8*3 do byte(0) end
-    section{"vectors", org=0xfffc} word(main,main)
+    section{"vectors", org=0xfffc} dc.w main if irq then dc.w main end
 end
 
 -- rom0 refers to the last one in ROM, ie the one always mapped to 0xF800-0xFFFF,
 -- such that changing the rom count does not change its index
-mappers['3F'] = function(count)
+mappers['3F'] = function(count, irq)
     function switchrom(i) assert(i>=0 and i<count-1) lda#i sta 0x3f end
     local symbols=cpu.symbols for k,v in pairs(vcs) do -- remap TIA to 0x40-0x7F
         if v<0x40 then v=v+0x40 vcs[k]=v symbols[k]=v end
@@ -148,10 +263,10 @@ mappers['3F'] = function(count)
     end
     local o = 0x800 * (count-1) + 0x10000
     rom0 = location{o, 0x7ff+o, rorg=0xf800}
-    section{"vectors", org=0xfffc} word(main,main)
+    section{"vectors", org=0xfffc} dc.w main if irq then dc.w main end
 end
 
-mappers.E7 = function()
+mappers.E7 = function(irq)
     function switchrom(i) assert(i>=0 and i<7) bit 0x1fe0+i end
     function enableram() bit 0x1fe7 end
     function switchram(i) assert(i>=0 and i<4) bit 0x1fe8+i end
@@ -161,56 +276,58 @@ mappers.E7 = function()
     end
     rom7 = location{0xf800, 0xffff, rorg=0xf800}
     section{"switchtab", org=0xffe0} for i=1,12 do byte(0) end
-    section{"vectors", org=0xfffc} word(main,main)
+    section{"vectors", org=0xfffc} dc.w main if irq then dc.w main end
 end
 
-mappers.F0 = function()
+mappers.F0 = function(irq)
     function switchrom() lda 0x1ff0 end
     for bi=0,15 do
         local o = bi*0x1000 + 0x1000
         _ENV['rom' .. bi] = location{o, o+0xfff, rorg=0xf000}
         local start=section{"entry"..bi, org=o+0xffc-8}
-            @_loop switchrom() bne _loop
+            local l=label() switchrom() bne l
             if bi==0 then jmp main end
         section{"switchtab"..bi, org=o+0xff0} byte(bi)
-        section{"vectors"..bi, org=o+0xffc} word(start,start)
+        section{"vectors"..bi, org=o+0xffc} dc.w start if irq then dc.w start end
     end
 end
 
-local bank_stubs2 = function(hotspot0, hotspot1)
+local bank_stubs2 = function(irq, hotspot0, hotspot1)
     function switchrom(i)
         if i==0 then bit hotspot0
         elseif i==1 then bit hotspot1
         else error("invalid rom index: " .. i) end
     end
+    far = far
     local base = 0xe000
     for bi=0,1 do
         local o = base+(bi<<12)
         _ENV['rom' .. bi] = location{o, o+0xfff, rorg=0xf000}
         local start=section{"entry"..bi, org=o+0xffc-6} switchrom(0) if bi==0 then jmp main end
-        section{"vectors"..bi, org=o+0xffc} word(start,start)
+        section{"vectors"..bi, org=o+0xffc} dc.w start if irq then dc.w start end
     end
 end
-mappers.UA = function() bank_stubs2(0x220, 0x240) end
+mappers.UA = function(irq) bank_stubs2(irq, 0x220, 0x240) end
-mappers['0840'] = function() bank_stubs2(0x800, 0x840) end
+mappers['0840'] = function(irq) bank_stubs2(irq, 0x800, 0x840) end
-mappers.SB = function(count)
+mappers.SB = function(count, irq)
     function switchrom(i) assert(i>=0 and i<count) bit 0x800+i end
+    far = far
     for bi=0,count-1 do
         local o = bi*0x1000 + 0x1000
         _ENV['rom' .. bi] = location{o, o+0xfff, rorg=0xf000}
         local start=section{"entry"..bi, org=o+0xffc-6} switchrom(0) if bi==0 then jmp main end
-        section{"vectors"..bi, org=o+0xffc} word(start,start)
+        section{"vectors"..bi, org=o+0xffc} dc.w start if irq then dc.w start end
     end
 end
 
-mappers['3E'] = function(rom_count, ram_count)
+mappers['3E'] = function(rom_count, ram_count, irq)
-    mappers['3F'](rom_count)
+    mappers['3F'](rom_count, irq)
     function switchram(i) assert(i>=0 and i<ram_count-1) lda#i sta 0x3E end
 end
 
 -- rom0 refers to the last 1k in ROM, which is mapped automatically on reset,
 -- such that changing the rom count does not change its index
-mappers.MC = function(rom_count, ram_count)
+mappers.MC = function(rom_count, ram_count, irq)
     for i=0,3 do
         _ENV['switchrom'..i] = function(i) assert(i>=0 and i<128) lda#i sta 0x3c+i end
         _ENV['switchram'..i] = function(i) assert(i>=0 and i<128) lda#i+0x80 sta 0x3c+i end
@@ -220,17 +337,18 @@ mappers.MC = function(rom_count, ram_count)
         _ENV["rom"..(count-1-bi)] = location{o, 0x3ff+o, rorg=0xf000+(o&0xfff)}
     end
     local start=section("entry") switchrom3(0) jmp main
-    section{"vectors", org=0xfffc} word(start,start)
+    section{"vectors", org=0xfffc} dc.w start if irq then dc.w start end
 end
 
-mappers.X07 = function()
+mappers.X07 = function(irq)
     function switchrom(i) assert(i>=0 and i<16) bit 0x80b+(i<<4) end
+    far = far
     -- map TIA also to 0x40-0x7F: use VSYNC for bank 14, and VSYNC2 for bank 15
     vcs.VSYNC2=0x40 cpu.symbols.VSYNC2=0x40
     for bi=0,count-1 do
         local o = bi*0x1000 + 0x1000
         _ENV['rom' .. bi] = location{o, o+0xfff, rorg=0xf000}
         local start=section{"entry"..bi, org=o+0xffc-6} switchrom(0) if bi==0 then jmp main end
-        section{"vectors"..bi, org=o+0xffc} word(start,start)
+        section{"vectors"..bi, org=o+0xffc} dc.w start if irq then dc.w start end
     end
 end