diff --git a/Lua/inject.lua b/Lua/inject.lua
index 90ef787..639ec5f 100644
--- a/Lua/inject.lua
+++ b/Lua/inject.lua
@@ -108,6 +108,7 @@ local function inject(fn)
         dprint(("%08X"):format(pos), line)
         pos = pos % 0x80000000
         size = size + 1
+        -- FIXME: doesn't detect .skip/.space directives
         if pos > cons_pos and (pos < inject_end or cons_pos == pos - 1) then
             cons_pos = pos
         end
diff --git a/Lua/inject/dpad control.asm b/Lua/inject/dpad control.asm
index 4b8070a..45a3f7c 100644
--- a/Lua/inject/dpad control.asm	
+++ b/Lua/inject/dpad control.asm	
@@ -13,7 +13,7 @@ dpad_control:
 dpad_values:
     // use table of values for branchless operation
     .byte 0,    1,    -1,   0
-    .byte -16,  -8,   -32,  -16
-    .byte +16,  +32,  +8,   +16
+    .byte -16,  -4,   -64,  -16
+    .byte +16,  +64,  +4,   +16
     .byte 0,    1,    -1,   0
 .align
diff --git a/Lua/inject/print.asm b/Lua/inject/print.asm
index 956df91..3314b51 100644
--- a/Lua/inject/print.asm
+++ b/Lua/inject/print.asm
@@ -34,10 +34,10 @@
     jpop    4, 1, ra
 
 fmt:
-    .byte 0x25,0x73,0x00 // %s
+    .asciiz "%s"
 .align
 str:
-    .byte 0x68,0x65,0x79,0x00 // hey
+    .asciiz "hey"
 .align
 
 .include "simple text.asm"
@@ -72,10 +72,9 @@ spawned:
 buffer_pos:
     .word 0
 
-// we'll just let this overflow
-.align 8
+.align 4
 buffer:
-    .word 0
+    .skip 0x3000
 
 // overwrite (not hook) the debug printing function
 .org 0x800021B0
diff --git a/Lua/inject/spawn.asm b/Lua/inject/spawn.asm
index 394082d..f59e580 100644
--- a/Lua/inject/spawn.asm
+++ b/Lua/inject/spawn.asm
@@ -2,6 +2,8 @@
 [button_R]: 0x0010
 [button_any]: 0x0F20
 
+[min_actor_no]: 0
+
 [hold_delay_amount]: 3
 
     push    4, s0, s1, s2, s3, s4, ra,
@@ -40,7 +42,7 @@
     mov     a0, s3
     andi    s3, v0, 0xFFFF
 +: // set min/max on actor number
-    subi    t4, s0, 1
+    subi    t4, s0, @min_actor_no
     bgez    t4, +
     nop
     li      s0, @max_actor_no
@@ -48,7 +50,7 @@
     subi    t4, s0, @max_actor_no
     blez    t4, +
     nop
-    li      s0, 1
+    li      s0, @min_actor_no
 +: // spawn
     andi    t3, s2, @button_L
     beqz    t3, return
@@ -87,7 +89,7 @@ selected:
     .word 0
 
 fmt:
-    .byte 0x25,0x30,0x34,0x58,0x00 // %04X
+    .asciiz "%04X"
 .align
 
 .include "dpad control.asm"
@@ -97,7 +99,24 @@ fmt:
 hold_delay:
     .word 0
 
+object_spawn_wrap:
+    // a0: object table
+    // a1: object number
+    beqz    a0, +
+    nop
+    beqi    a0, 1, +
+    nop
+    beqi    a0, 2, +
+    nop
+    jal     @object_spawn
+    nop
++:
+    jr
+    nop
+
 .org @object_index
+    // a0: object table
+    // a1: object number
     // we have space for 22 instructions (on debug, 23 on 1.0?)
     push    4, ra, 1
     mov     t0, a0
@@ -116,8 +135,6 @@ hold_delay:
     addi    t0, t0, 68
     bnez    t1, -
     nop
-    // NOTE: this allows object 0002 to load in places it's not meant to.
-    // this can mess up door graphics (among other things?)
     jal     @object_spawn
     nop
     //subiu   v0, r0, -1 // original code
diff --git a/Lua/lib/lips/Dumper.lua b/Lua/lib/lips/Dumper.lua
index faacf02..fb54c93 100644
--- a/Lua/lib/lips/Dumper.lua
+++ b/Lua/lib/lips/Dumper.lua
@@ -1,13 +1,13 @@
-local insert = table.insert
 local floor = math.floor
+local format = string.format
+local insert = table.insert
 
 local data = require "lips.data"
+local util = require "lips.util"
 
-local function bitrange(x, lower, upper)
-    return floor(x/2^lower) % 2^(upper - lower + 1)
-end
+local bitrange = util.bitrange
 
-local Dumper = require("lips.Class")()
+local Dumper = util.Class()
 function Dumper:init(writer, fn, options)
     self.writer = writer
     self.fn = fn or '(string)'
@@ -32,16 +32,16 @@ function Dumper:push_instruction(t)
     self:advance(4)
 end
 
-function Dumper:add_instruction_j(line, o, T)
-    self:push_instruction{line=line, o, T}
+function Dumper:add_instruction_j(fn, line, o, T)
+    self:push_instruction{fn=fn, line=line, o, T}
 end
 
-function Dumper:add_instruction_i(line, o, s, t, i)
-    self:push_instruction{line=line, o, s, t, i}
+function Dumper:add_instruction_i(fn, line, o, s, t, i)
+    self:push_instruction{fn=fn, line=line, o, s, t, i}
 end
 
-function Dumper:add_instruction_r(line, o, s, t, d, f, c)
-    self:push_instruction{line=line, o, s, t, d, f, c}
+function Dumper:add_instruction_r(fn, line, o, s, t, d, f, c)
+    self:push_instruction{fn=fn, line=line, o, s, t, d, f, c}
 end
 
 function Dumper:add_label(name)
@@ -57,6 +57,8 @@ function Dumper:add_bytes(line, ...)
         t = {}
         t.kind = 'bytes'
         t.size = 0
+        t.fn = self.fn
+        t.line = self.line
     end
     t.line = line
     for _, b in ipairs{...} do
@@ -69,9 +71,12 @@ function Dumper:add_bytes(line, ...)
     self:advance(t.size)
 end
 
-function Dumper:add_directive(line, name, a, b)
+function Dumper:add_directive(fn, line, name, a, b)
+    self.fn = fn
+    self.line = line
     local t = {}
-    t.line = line
+    t.fn = self.fn
+    t.line = self.line
     if name == 'BYTE' then
         self:add_bytes(line, a % 0x100)
     elseif name == 'HALFWORD' then
@@ -79,11 +84,17 @@ function Dumper:add_directive(line, name, a, b)
         local b1 = bitrange(a, 8, 15)
         self:add_bytes(line, b1, b0)
     elseif name == 'WORD' then
-        local b0 = bitrange(a, 0, 7)
-        local b1 = bitrange(a, 8, 15)
-        local b2 = bitrange(a, 16, 23)
-        local b3 = bitrange(a, 24, 31)
-        self:add_bytes(line, b3, b2, b1, b0)
+        if type(a) == 'string' then
+            local t = {line=line, kind='label', name=a}
+            insert(self.commands, t)
+            self:advance(4)
+        else
+            local b0 = bitrange(a, 0, 7)
+            local b1 = bitrange(a, 8, 15)
+            local b2 = bitrange(a, 16, 23)
+            local b3 = bitrange(a, 24, 31)
+            self:add_bytes(line, b3, b2, b1, b0)
+        end
     elseif name == 'ORG' then
         t.kind = 'goto'
         t.addr = a
@@ -92,11 +103,13 @@ function Dumper:add_directive(line, name, a, b)
         self:advance(0)
     elseif name == 'ALIGN' then
         t.kind = 'ahead'
-        local align = a*2
-        if align == 0 then
+        local align
+        if a == 0 then
             align = 4
-        elseif align < 0 then
+        elseif a < 0 then
             self:error('negative alignment')
+        else
+            align = 2^a
         end
         local temp = self.pos + align - 1
         t.skip = temp - (temp % align) - self.pos
@@ -114,18 +127,20 @@ function Dumper:add_directive(line, name, a, b)
     end
 end
 
-function Dumper:desym(tok)
-    -- FIXME: errors can give wrong filename, also off by one
-    if type(tok[2]) == 'number' then
-        return tok[2]
-    elseif tok[1] == 'LABELSYM' then
-        local label = self.labels[tok[2]]
+function Dumper:desym(t)
+    if type(t.tok) == 'number' then
+        return t.tok
+    elseif t.tt == 'REG' then
+        assert(data.all_registers[t.tok], 'Internal Error: unknown register')
+        return data.registers[t.tok] or data.fpu_registers[t.tok] or data.sys_registers[t.tok]
+    elseif t.tt == 'LABELSYM' then
+        local label = self.labels[t.tok]
         if label == nil then
             self:error('undefined label')
         end
         return label
-    elseif tok[1] == 'LABELREL' then
-        local label = self.labels[tok[2]]
+    elseif t.tt == 'LABELREL' then
+        local label = self.labels[t.tok]
         if label == nil then
             self:error('undefined label')
         end
@@ -137,57 +152,43 @@ function Dumper:desym(tok)
         end
         return rel % 0x10000
     end
-    self:error('failed to desym') -- internal error?
+    error('Internal Error: failed to desym')
 end
 
-function Dumper:toval(tok)
-    if tok == nil then
-        self:error('nil value')
-    elseif type(tok) == 'number' then
-        return tok
-    elseif data.all_registers[tok] then
-        return data.registers[tok] or data.fpu_registers[tok] or data.sys_registers[tok]
+function Dumper:toval(t)
+    assert(type(t) == 'table', 'Internal Error: invalid value')
+
+    local val = self:desym(t)
+
+    if t.index then
+        val = val % 0x80000000
+        val = floor(val/4)
     end
-    if type(tok) == 'table' then
-        if #tok ~= 2 then
-            self:error('invalid token')
-        end
-        if tok[1] == 'UPPER' then
-            local val = self:desym(tok[2])
-            return bitrange(val, 16, 31)
-        elseif tok[1] == 'LOWER' then
-            local val = self:desym(tok[2])
-            return bitrange(val, 0, 15)
-        elseif tok[1] == 'UPPEROFF' then
-            local val = self:desym(tok[2])
-            local upper = bitrange(val, 16, 31)
-            local lower = bitrange(val, 0, 15)
-            if lower >= 0x8000 then
-                -- accommodate for offsets being signed
-                upper = (upper + 1) % 0x10000
-            end
-            return upper
-        elseif tok[1] == 'SIGNED' then
-            local val = self:desym(tok[2])
-            if val >= 0x10000 or val < -0x8000 then
-                self:error('value out of range')
-            end
-            return val % 0x10000
-        elseif tok[1] == 'NEGATE' then
-            local val = -self:desym(tok[2])
-            if val >= 0x10000 or val < -0x8000 then
-                self:error('value out of range')
-            end
-            return val % 0x10000
-        elseif tok[1] == 'INDEX' then
-            local val = self:desym(tok[2]) % 0x80000000
-            val = floor(val/4)
-            return val
-        else
-            return self:desym(tok)
-        end
+    if t.negate then
+        val = -val
     end
-    self:error('invalid value') -- internal error?
+    if t.negate or t.signed then
+        if val >= 0x10000 or val < -0x8000 then
+            self:error('value out of range')
+        end
+        val = val % 0x10000
+    end
+
+    if t.portion == 'upper' then
+        val = bitrange(val, 16, 31)
+    elseif t.portion == 'lower' then
+        val = bitrange(val, 0, 15)
+    elseif t.portion == 'upperoff' then
+        local upper = bitrange(val, 16, 31)
+        local lower = bitrange(val, 0, 15)
+        if lower >= 0x8000 then
+            -- accommodate for offsets being signed
+            upper = (upper + 1) % 0x10000
+        end
+        val = upper
+    end
+
+    return val
 end
 
 function Dumper:validate(n, bits)
@@ -200,8 +201,8 @@ function Dumper:validate(n, bits)
     end
 end
 
-function Dumper:valvar(tok, bits)
-    local val = self:toval(tok)
+function Dumper:valvar(t, bits)
+    local val = self:toval(t)
     self:validate(val, bits)
     return val
 end
@@ -236,7 +237,7 @@ function Dumper:dump_instruction(t)
         lw = lw + self:valvar(t[5], 5)*0x40
         lw = lw + self:valvar(t[6], 6)
     else
-        error('Internal Error: unknown n-size', 1)
+        error('Internal Error: unknown n-size')
     end
 
     return uw, lw
@@ -245,9 +246,9 @@ end
 function Dumper:dump()
     self.pos = self.options.offset or 0
     for i, t in ipairs(self.commands) do
-        if t.line == nil then
-            error('Internal Error: no line number available')
-        end
+        assert(t.fn, 'Internal Error: no file name available')
+        assert(t.line, 'Internal Error: no line number available')
+        self.fn = t.fn
         self.line = t.line
         if t.kind == 'instruction' then
             local uw, lw = self:dump_instruction(t)
@@ -268,8 +269,16 @@ function Dumper:dump()
             else
                 self.pos = self.pos + t.skip
             end
+        elseif t.kind == 'label' then
+            local val = self:desym{'LABELSYM', t.name}
+            val = (val % 0x80000000) + 0x80000000
+            local b0 = bitrange(val, 0, 7)
+            local b1 = bitrange(val, 8, 15)
+            local b2 = bitrange(val, 16, 23)
+            local b3 = bitrange(val, 24, 31)
+            self:write{b3, b2, b1, b0}
         else
-            error('Internal Error: unknown command', 1)
+            error('Internal Error: unknown command')
         end
     end
 end
diff --git a/Lua/lib/lips/Lexer.lua b/Lua/lib/lips/Lexer.lua
index 922f454..33f6ebd 100644
--- a/Lua/lib/lips/Lexer.lua
+++ b/Lua/lib/lips/Lexer.lua
@@ -1,21 +1,26 @@
 local byte = string.byte
 local char = string.char
 local find = string.find
-local open = io.open
+local format = string.format
+local insert = table.insert
 
 local data = require "lips.data"
+local util = require "lips.util"
 
-local function readfile(fn)
-    local f = open(fn, 'r')
-    if not f then
-        error('could not open assembly file for reading: '..tostring(fn), 2)
-    end
-    local asm = f:read('*a')
-    f:close()
-    return asm
-end
+local simple_escapes = {
+    ['0']   = 0x00,
+    ['\\']  = 0x5C,
+    ['"']   = 0x22,
+    ['a']   = 0x07,
+    ['b']   = 0x08,
+    ['f']   = 0x0C,
+    ['n']   = 0x0A,
+    ['r']   = 0x0D,
+    ['t']   = 0x09,
+    ['v']   = 0x0B,
+}
 
-local Lexer = require("lips.Class")()
+local Lexer = util.Class()
 function Lexer:init(asm, fn, options)
     self.asm = asm
     self.fn = fn or '(string)'
@@ -139,8 +144,8 @@ function Lexer:lex_hex(yield)
     local entered = false
     while true do
         if self.chr == '\n' then
-            self:nextc()
             yield('EOL', '\n')
+            self:nextc()
         elseif self.ord == self.EOF then
             self:error('unexpected EOF; incomplete hex directive')
         elseif self.chr == ';' then
@@ -191,8 +196,8 @@ end
 function Lexer:lex_block_comment(yield)
     while true do
         if self.chr == '\n' then
-            self:nextc()
             yield('EOL', '\n')
+            self:nextc()
         elseif self.ord == self.EOF then
             self:error('unexpected EOF; incomplete block comment')
         elseif self.chrchr == '*/' then
@@ -206,14 +211,49 @@ function Lexer:lex_block_comment(yield)
 end
 
 function Lexer:lex_string(yield)
-    -- TODO: support escaping
     if self.chr ~= '"' then
-        self:error("expected opening double quote")
+        self:error('expected opening double quote')
+    end
+    self:nextc()
+
+    local bytes = {}
+    while true do
+        if self.chr == '\n' then
+            self:error('unimplemented')
+            yield('EOL', '\n')
+            self:nextc()
+        elseif self.ord == self.EOF then
+            self:nextc()
+            self:error('unexpected EOF; incomplete string')
+        elseif self.chr == '"' then
+            self:nextc()
+            break
+        elseif self.chr == '\\' then
+            self:nextc()
+            local simple = simple_escapes[self.chr]
+            if simple then
+                insert(bytes, simple)
+            else
+                self:error('unknown escape sequence')
+            end
+            self:nextc()
+        else
+            insert(bytes, byte(self.chr))
+            self:nextc()
+        end
+    end
+
+    yield('STRING', bytes)
+end
+
+function Lexer:lex_string_naive(yield) -- no escape sequences
+    if self.chr ~= '"' then
+        self:error('expected opening double quote')
     end
     self:nextc()
     local buff = self:read_chars('[^"\n]')
     if self.chr ~= '"' then
-        self:error("expected closing double quote")
+        self:error('expected closing double quote')
     end
     self:nextc()
     yield('STRING', buff)
@@ -222,13 +262,13 @@ end
 function Lexer:lex_include(_yield)
     self:read_chars('%s')
     local fn
-    self:lex_string(function(tt, tok)
+    self:lex_string_naive(function(tt, tok)
         fn = tok
     end)
     if self.options.path then
         fn = self.options.path..fn
     end
-    local sublexer = Lexer(readfile(fn), fn, self.options)
+    local sublexer = Lexer(util.readfile(fn), fn, self.options)
     sublexer:lex(_yield)
 end
 
@@ -238,8 +278,8 @@ function Lexer:lex(_yield)
     end
     while true do
         if self.chr == '\n' then
-            self:nextc()
             yield('EOL', '\n')
+            self:nextc()
         elseif self.ord == self.EOF then
             yield('EOF', self.EOF)
             break
@@ -268,24 +308,23 @@ function Lexer:lex(_yield)
             end
             self:nextc()
             yield('DEF', buff)
+        elseif self.chr == ']' then
+            self:error('unmatched closing bracket')
         elseif self.chr == '(' then
             self:nextc()
-            local buff = self:read_chars('[%w_]')
-            if self.chr ~= ')' then
-                self:error('invalid register name')
-            end
+            yield('OPEN', '(')
+        elseif self.chr == ')' then
             self:nextc()
-            local up = buff:upper()
-            if not data.all_registers[up] then
-                self:error('not a register')
-            end
-            yield('DEREF', up)
+            yield('CLOSE', ')')
         elseif self.chr == '.' then
             self:nextc()
             local buff = self:read_chars('[%w]')
             local up = buff:upper()
+            if data.directive_aliases[up] then
+                up = data.directive_aliases[up]
+            end
             if not data.all_directives[up] then
-                self:error('not a directive')
+                self:error('unknown directive')
             end
             if up == 'INC' or up == 'INCASM' or up == 'INCLUDE' then
                 yield('DIR', 'INC')
@@ -293,10 +332,16 @@ function Lexer:lex(_yield)
             else
                 yield('DIR', up)
             end
+        elseif self.chr == '"' then
+            self:lex_string(yield)
         elseif self.chr == '@' then
             self:nextc()
             local buff = self:read_chars('[%w_]')
             yield('DEFSYM', buff)
+        elseif self.chr == '%' then
+            self:nextc()
+            local call = self:read_chars('[%w_]')
+            yield('SPECIAL', call)
         elseif self.chr:find('[%a_]') then
             local buff = self:read_chars('[%w_.]')
             local up = buff:upper()
@@ -318,10 +363,6 @@ function Lexer:lex(_yield)
                 end
                 yield('LABELSYM', buff)
             end
-        elseif self.chr == ']' then
-            self:error('unmatched closing bracket')
-        elseif self.chr == ')' then
-            self:error('unmatched closing parenthesis')
         elseif self.chr == '+' or self.chr == '-' then
             local sign_chr = self.chr
             local sign = sign_chr == '+' and 1 or -1
diff --git a/Lua/lib/lips/Muncher.lua b/Lua/lib/lips/Muncher.lua
new file mode 100644
index 0000000..db54263
--- /dev/null
+++ b/Lua/lib/lips/Muncher.lua
@@ -0,0 +1,157 @@
+local format = string.format
+local insert = table.insert
+
+local data = require "lips.data"
+local util = require "lips.util"
+local Token = require "lips.Token"
+
+local arg_types = {
+    NUM = true,
+    REG = true,
+    DEFSYM = true,
+    LABELSYM = true,
+    RELLABELSYM = true,
+}
+
+local Muncher = util.Class()
+-- no base init method
+
+function Muncher:error(msg)
+    error(format('%s:%d: Error: %s', self.fn, self.line, msg), 2)
+end
+
+function Muncher:token(t, val)
+    -- note: call Token directly if you want to specify fn and line manually
+    if type(t) == 'table' then
+        t.fn = self.fn
+        t.line = self.line
+        return Token(t)
+    else
+        return Token(self.fn, self.line, t, val)
+    end
+end
+
+function Muncher:advance()
+    self.i = self.i + 1
+    self.t = self.tokens[self.i]
+    self.tt = self.t.tt
+    self.tok = self.t.tok
+    self.fn = self.t.fn
+    self.line = self.t.line
+    return self.t
+end
+
+function Muncher:is_EOL()
+    return self.tt == 'EOL' or self.tt == 'EOF'
+end
+
+function Muncher:expect_EOL()
+    if self:is_EOL() then
+        self:advance()
+        return
+    end
+    self:error('expected end of line')
+end
+
+function Muncher:optional_comma()
+    if self.tt == 'SEP' and self.tok == ',' then
+        self:advance()
+        return true
+    end
+end
+
+function Muncher:number()
+    if self.tt ~= 'NUM' then
+        self:error('expected number')
+    end
+    local t = self.t
+    self:advance()
+    return self:token(t)
+end
+
+function Muncher:string()
+    if self.tt ~= 'STRING' then
+        self:error('expected string')
+    end
+    local t = self.t
+    self:advance()
+    return self:token(t)
+end
+
+function Muncher:register(registers)
+    registers = registers or data.registers
+    if self.tt ~= 'REG' then
+        self:error('expected register')
+    end
+    local t = self.t
+    if not registers[t.tok] then
+        self:error('wrong type of register')
+    end
+    self:advance()
+    return self:token(t)
+end
+
+function Muncher:deref()
+    if self.tt ~= 'OPEN' then
+        self:error('expected opening parenthesis for dereferencing')
+    end
+    self:advance()
+    if self.tt ~= 'REG' then
+        self:error('expected register to dereference')
+    end
+    local t = self.t
+    self:advance()
+    if self.tt ~= 'CLOSE' then
+        self:error('expected closing parenthesis for dereferencing')
+    end
+    self:advance()
+    return self:token(t)
+end
+
+function Muncher:const(relative, no_label)
+    if self.tt ~= 'NUM' and self.tt ~= 'LABELSYM' then
+        self:error('expected constant')
+    end
+    if no_label and self.tt == 'LABELSYM' then
+        self:error('labels are not allowed here')
+    end
+    local t = self:token(self.t)
+    if relative and self.tt == 'LABELSYM' then
+        t.tt = 'LABELREL'
+    end
+    self:advance()
+    return t
+end
+
+function Muncher:special()
+    if self.tt ~= 'SPECIAL' then
+        self:error('expected special name to call')
+    end
+    local name = self.tok
+    self:advance()
+    if self.tt ~= 'OPEN' then
+        self:error('expected opening parenthesis for special call')
+    end
+
+    local args = {}
+    while true do
+        local arg = self:advance()
+        if not arg_types[arg.tt] then
+            self:error('invalid argument type')
+        else
+            self:advance()
+        end
+        if self.tt == 'SEP' then
+            insert(args, arg)
+        elseif self.tt == 'CLOSE' then
+            insert(args, arg)
+            break
+        else
+            self:error('unexpected token in argument list')
+        end
+    end
+
+    return name, args
+end
+
+return Muncher
diff --git a/Lua/lib/lips/Parser.lua b/Lua/lib/lips/Parser.lua
index f3e9bc3..e16e933 100644
--- a/Lua/lib/lips/Parser.lua
+++ b/Lua/lib/lips/Parser.lua
@@ -1,139 +1,79 @@
 local insert = table.insert
-local format = string.format
 
 local data = require "lips.data"
+local util = require "lips.util"
 local overrides = require "lips.overrides"
-local Dumper = require "lips.Dumper"
+local Token = require "lips.Token"
 local Lexer = require "lips.Lexer"
+local Dumper = require "lips.Dumper"
+local Muncher = require "lips.Muncher"
+local Preproc = require "lips.Preproc"
 
-local Parser = require("lips.Class")()
+local Parser = util.Class(Muncher)
 function Parser:init(writer, fn, options)
     self.fn = fn or '(string)'
     self.main_fn = self.fn
     self.options = options or {}
     self.dumper = Dumper(writer, fn, options)
-    self.defines = {}
-end
-
-function Parser:error(msg)
-    error(format('%s:%d: Error: %s', self.fn, self.line, msg), 2)
-end
-
-function Parser:advance()
-    self.i = self.i + 1
-    local t = self.tokens[self.i]
-    self.tt = t.tt
-    self.tok = t.tok
-    self.fn = t.fn
-    self.line = t.line
-    return t.tt, t.tok
-end
-
-function Parser:is_EOL()
-    return self.tt == 'EOL' or self.tt == 'EOF'
-end
-
-function Parser:expect_EOL()
-    if self:is_EOL() then
-        self:advance()
-        return
-    end
-    self:error('expected end of line')
-end
-
-function Parser:optional_comma()
-    if self.tt == 'SEP' and self.tok == ',' then
-        self:advance()
-        return true
-    end
-end
-
-function Parser:number()
-    if self.tt ~= 'NUM' then
-        self:error('expected number')
-    end
-    local value = self.tok
-    self:advance()
-    return value
 end
 
 function Parser:directive()
     local name = self.tok
     self:advance()
-    local line = self.line
+    local function add(...)
+        self.dumper:add_directive(self.fn, self.line, ...)
+    end
     if name == 'ORG' then
-        self.dumper:add_directive(line, name, self:number())
+        add(name, self:number().tok)
     elseif name == 'ALIGN' or name == 'SKIP' then
         if self:is_EOL() and name == 'ALIGN' then
-            self.dumper:add_directive(line, name, 0)
+            add(name, 0)
         else
             local size = self:number()
             if self:is_EOL() then
-                self.dumper:add_directive(line, name, size)
+                add(name, size)
             else
                 self:optional_comma()
-                self.dumper:add_directive(line, name, size, self:number())
+                add(name, size, self:number().tok)
             end
             self:expect_EOL()
         end
-    elseif name == 'BYTE' or name == 'HALFWORD' or name == 'WORD' then
-        self.dumper:add_directive(line, name, self:number())
+    elseif name == 'BYTE' or name == 'HALFWORD' then
+        add(name, self:number().tok)
         while not self:is_EOL() do
             self:advance()
             self:optional_comma()
-            self.dumper:add_directive(line, name, self:number())
+            add(name, self:number().tok)
+        end
+        self:expect_EOL()
+    elseif name == 'WORD' then -- allow labels in word directives
+        add(name, self:const().tok)
+        while not self:is_EOL() do
+            self:advance()
+            self:optional_comma()
+            add(name, self:const().tok)
         end
         self:expect_EOL()
-    elseif name == 'HEX' then
-        self:error('unimplemented')
     elseif name == 'INC' then
-        -- noop
+        -- noop, handled by lexer
+    elseif name == 'ASCII' or name == 'ASCIIZ' then
+        local bytes = self:string()
+        for i, number in ipairs(bytes.tok) do
+            add('BYTE', number)
+        end
+        if name == 'ASCIIZ' then
+            add('BYTE', 0)
+        end
+        self:expect_EOL()
     elseif name == 'INCBIN' then
         self:error('unimplemented')
-    elseif name == 'FLOAT' or name == 'ASCII' or name == 'ASCIIZ' then
+    elseif name == 'FLOAT' then
         self:error('unimplemented')
     else
         self:error('unknown directive')
     end
 end
 
-function Parser:register(t)
-    t = t or data.registers
-    if self.tt ~= 'REG' then
-        self:error('expected register')
-    end
-    local reg = self.tok
-    if not t[reg] then
-        self:error('wrong type of register')
-    end
-    self:advance()
-    return reg
-end
-
-function Parser:deref()
-    if self.tt ~= 'DEREF' then
-        self:error('expected register to dereference')
-    end
-    local reg = self.tok
-    self:advance()
-    return reg
-end
-
-function Parser:const(relative, no_label)
-    if self.tt ~= 'NUM' and self.tt ~= 'LABELSYM' then
-        self:error('expected constant')
-    end
-    if no_label and self.tt == 'LABELSYM' then
-        self:error('labels are not allowed here')
-    end
-    if relative and self.tt == 'LABELSYM' then
-        self.tt = 'LABELREL'
-    end
-    local t = {self.tt, self.tok}
-    self:advance()
-    return t
-end
-
 function Parser:format_in(informat)
     local args = {}
     for i=1,#informat do
@@ -146,33 +86,33 @@ function Parser:format_in(informat)
         elseif c == 't' and not args.rt then
             args.rt = self:register()
         elseif c == 'D' and not args.fd then
-            args.fd = self:register(fpu_registers)
+            args.fd = self:register(data.fpu_registers)
         elseif c == 'S' and not args.fs then
-            args.fs = self:register(fpu_registers)
+            args.fs = self:register(data.fpu_registers)
         elseif c == 'T' and not args.ft then
-            args.ft = self:register(fpu_registers)
+            args.ft = self:register(data.fpu_registers)
         elseif c == 'X' and not args.rd then
-            args.rd = self:register(sys_registers)
+            args.rd = self:register(data.sys_registers)
         elseif c == 'Y' and not args.rs then
-            args.rs = self:register(sys_registers)
+            args.rs = self:register(data.sys_registers)
         elseif c == 'Z' and not args.rt then
-            args.rt = self:register(sys_registers)
+            args.rt = self:register(data.sys_registers)
         elseif c == 'o' and not args.offset then
-            args.offset = {'SIGNED', self:const()}
+            args.offset = Token(self:const()):set('signed')
         elseif c == 'r' and not args.offset then
-            args.offset = {'SIGNED', self:const('relative')}
+            args.offset = Token(self:const('relative')):set('signed')
         elseif c == 'i' and not args.immediate then
             args.immediate = self:const(nil, 'no label')
         elseif c == 'I' and not args.index then
-            args.index = {'INDEX', self:const()}
+            args.index = Token(self:const()):set('index')
         elseif c == 'k' and not args.immediate then
-            args.immediate = {'NEGATE', self:const(nil, 'no label')}
+            args.immediate = Token(self:const(nil, 'no label')):set('negate')
         elseif c == 'K' and not args.immediate then
-            args.immediate = {'SIGNED', self:const(nil, 'no label')}
+            args.immediate = Token(self:const(nil, 'no label')):set('signed')
         elseif c == 'b' and not args.base then
             args.base = self:deref()
         else
-            error('Internal Error: invalid input formatting string', 1)
+            error('Internal Error: invalid input formatting string')
         end
         if c2:find('[dstDSTorIikKXYZ]') then
             self:optional_comma()
@@ -191,38 +131,38 @@ function Parser:format_out_raw(outformat, first, args, const, formatconst)
     for i=1,#outformat do
         local c = outformat:sub(i, i)
         if c == 'd' then
-            out[#out+1] = args.rd
+            out[#out+1] = self:token(args.rd)
         elseif c == 's' then
-            out[#out+1] = args.rs
+            out[#out+1] = self:token(args.rs)
         elseif c == 't' then
-            out[#out+1] = args.rt
+            out[#out+1] = self:token(args.rt)
         elseif c == 'D' then
-            out[#out+1] = args.fd
+            out[#out+1] = self:token(args.fd)
         elseif c == 'S' then
-            out[#out+1] = args.fs
+            out[#out+1] = self:token(args.fs)
         elseif c == 'T' then
-            out[#out+1] = args.ft
+            out[#out+1] = self:token(args.ft)
         elseif c == 'o' then
-            out[#out+1] = args.offset
+            out[#out+1] = self:token(args.offset)
         elseif c == 'i' then
-            out[#out+1] = args.immediate
+            out[#out+1] = self:token(args.immediate)
         elseif c == 'I' then
-            out[#out+1] = args.index
+            out[#out+1] = self:token(args.index)
         elseif c == 'b' then
-            out[#out+1] = args.base
+            out[#out+1] = self:token(args.base)
         elseif c == '0' then
-            out[#out+1] = 0
+            out[#out+1] = self:token(0)
         elseif c == 'C' then
-            out[#out+1] = const
+            out[#out+1] = self:token(const)
         elseif c == 'F' then
-            out[#out+1] = formatconst
+            out[#out+1] = self:token(formatconst)
         end
     end
     local f = lookup[#outformat]
     if f == nil then
-        error('Internal Error: invalid output formatting string', 1)
+        error('Internal Error: invalid output formatting string')
     end
-    f(self.dumper, self.line, first, out[1], out[2], out[3], out[4], out[5])
+    f(self.dumper, self.fn, self.line, first, out[1], out[2], out[3], out[4], out[5])
 end
 
 function Parser:format_out(t, args)
@@ -234,33 +174,41 @@ function Parser:instruction()
     local h = data.instructions[name]
     self:advance()
 
-    -- FIXME: errors thrown here probably have the wrong line number (+1)
-
     if h == nil then
-        self:error('undefined instruction')
+        error('Internal Error: undefined instruction')
     elseif overrides[name] then
         overrides[name](self, name)
-    elseif h[2] == 'tob' then -- or h[2] == 'Tob' then
+    elseif h[2] == 'tob' then -- TODO: or h[2] == 'Tob' then
         local lui = data.instructions['LUI']
+        local addu = data.instructions['ADDU']
         local args = {}
         args.rt = self:register()
         self:optional_comma()
-        local o = self:const()
-        local is_label = o[1] == 'LABELSYM'
-        if self:is_EOL() then
-            local lui_args = {}
-            lui_args.immediate = {'UPPEROFF', o}
-            lui_args.rt = 'AT'
-            self:format_out(lui, lui_args)
-            args.offset = {'LOWER', o}
-            args.base = 'AT'
-        else
-            if is_label then
-                self:error('labels cannot be used as offsets')
-            end
-            args.offset = {'SIGNED', o}
-            self:optional_comma()
+        if self.tt == 'OPEN' then
+            args.offset = 0
             args.base = self:deref()
+        else -- NUM or LABELSYM
+            local lui_args = {}
+            local addu_args = {}
+            local o = self:const()
+            args.offset = self:token(o)
+            if not o.portion then
+                args.offset:set('portion', 'lower')
+            end
+            if not o.portion and (o.tt == 'LABELSYM' or o.tok >= 0x80000000) then
+                lui_args.immediate = Token(o):set('portion', 'upperoff')
+                lui_args.rt = 'AT'
+                self:format_out(lui, lui_args)
+                if not self:is_EOL() then
+                    addu_args.rd = 'AT'
+                    addu_args.rs = 'AT'
+                    addu_args.rt = self:deref()
+                    self:format_out(addu, addu_args)
+                end
+                args.base = 'AT'
+            else
+                args.base = self:deref()
+            end
         end
         self:format_out(h, args)
     elseif h[2] ~= nil then
@@ -273,7 +221,6 @@ function Parser:instruction()
 end
 
 function Parser:tokenize(asm)
-    self.tokens = {}
     self.i = 0
 
     local routine = coroutine.create(function()
@@ -281,103 +228,27 @@ function Parser:tokenize(asm)
         lexer:lex(coroutine.yield)
     end)
 
-    local function lex()
-        local t = {}
+    local tokens = {}
+    while true do
         local ok, a, b, c, d = coroutine.resume(routine)
         if not ok then
             a = a or 'Internal Error: lexer coroutine has stopped'
             error(a)
         end
-        t.tt = a
-        t.tok = b
-        t.fn = c
-        t.line = d
-        insert(self.tokens, t)
-        return t.tt, t.tok, t.fn, t.line
-    end
+        assert(a, 'Internal Error: missing token')
 
-    -- first pass: collect tokens, constants, and relative labels.
-    -- can't do more because instruction size can depend on a constant's size
-    -- and labels depend on instruction size.
-    -- note however, instruction size does not depend on label size.
-    -- this would cause a recursive problem to solve,
-    -- which is too much for our simple assembler.
-    local plus_labels = {} -- constructed forwards
-    local minus_labels = {} -- constructed backwards
-    while true do
-        local tt, tok, fn, line = lex()
-        self.fn = fn
-        self.line = line
-        if tt == 'DEF' then
-            local tt2, tok2 = lex()
-            if tt2 ~= 'NUM' then
-                self:error('expected number for define')
-            end
-            self.defines[tok] = tok2
-        elseif tt == 'RELLABEL' then
-            if tok == '+' then
-                insert(plus_labels, #self.tokens)
-            elseif tok == '-' then
-                insert(minus_labels, 1, #self.tokens)
-            else
-                error('Internal Error: unexpected token for relative label', 1)
-            end
-        elseif tt == 'EOL' then
-            -- noop
-        elseif tt == 'EOF' then
-            if fn == self.main_fn then
-                break
-            end
-        elseif tt == nil then
-            error('Internal Error: missing token', 1)
+        local t = Token(c, d, a, b)
+        insert(tokens, t)
+
+        if t.tt == 'EOF' and t.fn == self.main_fn then
+            break
         end
     end
 
-    -- resolve defines and relative labels
-    for i, t in ipairs(self.tokens) do
-        self.fn = t.fn
-        self.line = t.line
-        if t.tt == 'DEFSYM' then
-            t.tt = 'NUM'
-            t.tok = self.defines[t.tok]
-            if t.tok == nil then
-                self:error('undefined define') -- uhhh nice wording
-            end
-        elseif t.tt == 'RELLABEL' then
-            t.tt = 'LABEL'
-            -- exploits the fact that user labels can't begin with a number
-            t.tok = tostring(i)
-        elseif t.tt == 'RELLABELSYM' then
-            t.tt = 'LABELSYM'
-            local rel = t.tok
-            local seen = 0
-            -- TODO: don't iterate over *every* label, just the ones nearby
-            if rel > 0 then
-                for _, label_i in ipairs(plus_labels) do
-                    if label_i > i then
-                        seen = seen + 1
-                        if seen == rel then
-                            t.tok = tostring(label_i)
-                            break
-                        end
-                    end
-                end
-            else
-                for _, label_i in ipairs(minus_labels) do
-                    if label_i < i then
-                        seen = seen - 1
-                        if seen == rel then
-                            t.tok = tostring(label_i)
-                            break
-                        end
-                    end
-                end
-            end
-            if seen ~= rel then
-                self:error('could not find appropriate relative label')
-            end
-        end
-    end
+    local preproc = Preproc(self.options)
+    self.tokens = preproc:process(tokens)
+
+    assert(#self.tokens > 0, 'Internal Error: no tokens after preprocessing')
 end
 
 function Parser:parse(asm)
@@ -392,9 +263,6 @@ function Parser:parse(asm)
         elseif self.tt == 'EOL' then
             -- empty line
             self:advance()
-        elseif self.tt == 'DEF' then
-            self:advance()
-            self:advance()
         elseif self.tt == 'DIR' then
             self:directive()
         elseif self.tt == 'LABEL' then
diff --git a/Lua/lib/lips/Preproc.lua b/Lua/lib/lips/Preproc.lua
new file mode 100644
index 0000000..07f0e72
--- /dev/null
+++ b/Lua/lib/lips/Preproc.lua
@@ -0,0 +1,137 @@
+local insert = table.insert
+
+local data = require "lips.data"
+local util = require "lips.util"
+local Muncher = require "lips.Muncher"
+local Token = require "lips.Token"
+
+local Preproc = util.Class(Muncher)
+function Preproc:init(options)
+    self.options = options or {}
+end
+
+function Preproc:process(tokens)
+    self.tokens = tokens
+
+    local defines = {}
+    local plus_labels = {} -- constructed forwards
+    local minus_labels = {} -- constructed backwards
+
+    -- first pass: resolve defines, collect relative labels
+    local new_tokens = {}
+    self.i = 0
+    while self.i < #self.tokens do
+        local t = self:advance()
+        if t.tt == nil then
+            error('Internal Error: missing token')
+        elseif t.tt == 'DEF' then
+            local t2 = self:advance()
+            if t2.tt ~= 'NUM' then
+                self:error('expected number for define')
+            end
+            defines[t.tok] = t2.tok
+        elseif t.tt == 'DEFSYM' then
+            local tt = 'NUM'
+            local tok = defines[t.tok]
+            if tok == nil then
+                self:error('undefined define') -- uhhh nice wording
+            end
+            insert(new_tokens, self:token(tt, tok))
+        elseif t.tt == 'RELLABEL' then
+            if t.tok == '+' then
+                insert(plus_labels, #new_tokens + 1)
+            elseif t.tok == '-' then
+                insert(minus_labels, 1, #new_tokens + 1)
+            else
+                error('Internal Error: unexpected token for relative label')
+            end
+            insert(new_tokens, t)
+        else
+            insert(new_tokens, t)
+        end
+    end
+
+    -- second pass: resolve relative labels
+    for i, t in ipairs(new_tokens) do
+        self.fn = t.fn
+        self.line = t.line
+        if t.tt == 'RELLABEL' then
+            t.tt = 'LABEL'
+            -- exploits the fact that user labels can't begin with a number
+            t.tok = tostring(i)
+        elseif t.tt == 'RELLABELSYM' then
+            t.tt = 'LABELSYM'
+
+            local rel = t.tok
+            local seen = 0
+            -- TODO: don't iterate over *every* label, just the ones nearby
+            if rel > 0 then
+                for _, label_i in ipairs(plus_labels) do
+                    if label_i > i then
+                        seen = seen + 1
+                        if seen == rel then
+                            t.tok = tostring(label_i)
+                            break
+                        end
+                    end
+                end
+            else
+                for _, label_i in ipairs(minus_labels) do
+                    if label_i < i then
+                        seen = seen - 1
+                        if seen == rel then
+                            t.tok = tostring(label_i)
+                            break
+                        end
+                    end
+                end
+            end
+
+            if seen ~= rel then
+                self:error('could not find appropriate relative label')
+            end
+        end
+    end
+
+    self.tokens = new_tokens
+    new_tokens = {}
+
+    -- third pass: resolve specials
+    self.i = 0
+    while self.i < #self.tokens do
+        local t = self:advance()
+        if t.tt == 'SPECIAL' then
+            local name, args = self:special()
+            -- TODO: split to its own file, not unlike overrides.lua
+            if name == 'hi' then
+                if #args ~= 1 then
+                    self:error('%hi expected exactly one argument')
+                end
+                local tnew = self:token(args[1]):set('portion', 'upperoff')
+                insert(new_tokens, tnew)
+            elseif name == 'up' then
+                if #args ~= 1 then
+                    self:error('%up expected exactly one argument')
+                end
+                local tnew = self:token(args[1]):set('portion', 'upper')
+                insert(new_tokens, tnew)
+            elseif name == 'lo' then
+                if #args ~= 1 then
+                    self:error('%lo expected exactly one argument')
+                end
+                local tnew = self:token(args[1]):set('portion', 'lower')
+                insert(new_tokens, tnew)
+            else
+                self:error('unknown special')
+            end
+        else
+            insert(new_tokens, t)
+        end
+    end
+
+    self.tokens = new_tokens
+
+    return self.tokens
+end
+
+return Preproc
diff --git a/Lua/lib/lips/Token.lua b/Lua/lib/lips/Token.lua
new file mode 100644
index 0000000..7978fec
--- /dev/null
+++ b/Lua/lib/lips/Token.lua
@@ -0,0 +1,60 @@
+local util = require "lips.util"
+
+local Token = util.Class()
+function Token:init(...)
+    local args = {...}
+    if #args == 1 then
+        local t = args[1]
+        if type(t) == 'table' then
+            for k, v in pairs(t) do
+                self[k] = v
+            end
+        end
+    elseif #args == 3 then
+        self.fn = args[1]
+        self.line = args[2]
+        local t = args[3]
+        if type(t) == 'table' then
+            self.tt = t[1]
+            self.tok = t[2]
+        elseif type(t) == 'string' then
+            self.tt = 'REG'
+            self.tok = t
+        elseif type(t) == 'number' then
+            self.tt = 'NUM'
+            self.tok = t
+        else
+            error('Internal Error: unknown type to construct', 3)
+        end
+    elseif #args == 4 then
+        self.fn = args[1]
+        self.line = args[2]
+        self.tt = args[3]
+        self.tok = args[4]
+    else
+        error('Internal Error: init takes 1, 3 or 4 arguments', 3)
+    end
+    if not self.fn then
+        error('Internal Error: tokens require a filename', 3)
+    end
+    if not self.line then
+        error('Internal Error: tokens require a line number', 3)
+    end
+    if not self.tt then
+        error('Internal Error: token is missing a type', 3)
+    end
+    if not self.tok then
+        error('Internal Error: token is missing a value', 3)
+    end
+    return self
+end
+
+function Token:set(key, value)
+    if value == nil then
+        value = true
+    end
+    self[key] = value
+    return self
+end
+
+return Token
diff --git a/Lua/lib/lips/data.lua b/Lua/lib/lips/data.lua
index 5129589..41656a0 100644
--- a/Lua/lib/lips/data.lua
+++ b/Lua/lib/lips/data.lua
@@ -29,13 +29,19 @@ data.fpu_registers = {
 }
 
 data.all_directives = {
-    'ALIGN', 'SKIP',
+    'ORG', 'ALIGN', 'SKIP',
     'ASCII', 'ASCIIZ',
-    'BYTE', 'HALFWORD', 'WORD', 'FLOAT',
+    'BYTE', 'HALFWORD', 'WORD',
     --'HEX', -- excluded here due to different syntax
     'INC', 'INCASM', 'INCLUDE',
     'INCBIN',
-    'ORG',
+    -- these are unlikely to be implemented
+    'FLOAT', 'DOUBLE',
+}
+
+data.directive_aliases = {
+    SPACE = 'SKIP',
+    HALF = 'HALFWORD',
 }
 
 data.all_registers = {}
diff --git a/Lua/lib/lips/init.lua b/Lua/lib/lips/init.lua
index d3dfac7..76768bb 100644
--- a/Lua/lib/lips/init.lua
+++ b/Lua/lib/lips/init.lua
@@ -1,6 +1,4 @@
--- split lips.lua
-
-local assembler = {
+local lips = {
     _DESCRIPTION = 'Assembles MIPS assembly files for the R4300i CPU.',
     _URL = 'https://github.com/notwa/lips/',
     _LICENSE = [[
@@ -12,21 +10,10 @@ local assembler = {
     ]],
 }
 
-local open = io.open
-
+local util = require "lips.util"
 local Parser = require "lips.Parser"
 
-local function readfile(fn)
-    local f = open(fn, 'r')
-    if not f then
-        error('could not open assembly file for reading: '..tostring(fn), 2)
-    end
-    local asm = f:read('*a')
-    f:close()
-    return asm
-end
-
-function assembler.word_writer()
+function lips.word_writer()
     local buff = {}
     local max = -1
     return function(pos, b)
@@ -47,13 +34,13 @@ function assembler.word_writer()
     end
 end
 
-function assembler.assemble(fn_or_asm, writer, options)
+function lips.assemble(fn_or_asm, writer, options)
     -- assemble MIPS R4300i assembly code.
     -- if fn_or_asm contains a newline; treat as assembly, otherwise load file.
     -- returns error message on error, or nil on success.
     fn_or_asm = tostring(fn_or_asm)
     local default_writer = not writer
-    writer = writer or assembler.word_writer()
+    writer = writer or lips.word_writer()
     options = options or {}
 
     local function main()
@@ -63,7 +50,7 @@ function assembler.assemble(fn_or_asm, writer, options)
             asm = fn_or_asm
         else
             fn = fn_or_asm
-            asm = readfile(fn)
+            asm = util.readfile(fn)
             options.path = fn:match(".*/")
         end
 
@@ -83,7 +70,7 @@ function assembler.assemble(fn_or_asm, writer, options)
     end
 end
 
-return setmetatable(assembler, {
+return setmetatable(lips, {
     __call = function(self, ...)
         return self.assemble(...)
     end,
diff --git a/Lua/lib/lips/overrides.lua b/Lua/lib/lips/overrides.lua
index dfbce6e..6893414 100644
--- a/Lua/lib/lips/overrides.lua
+++ b/Lua/lib/lips/overrides.lua
@@ -1,6 +1,8 @@
 local insert = table.insert
 
 local data = require "lips.data"
+local util = require "lips.util"
+
 local instructions = data.instructions
 
 local overrides = {}
@@ -17,26 +19,33 @@ function overrides.LI(self, name)
 
     -- for us, this is just semantics. for a "real" assembler,
     -- LA could add appropriate RELO LUI/ADDIU directives.
-    if im[1] == 'LABELSYM' then
+    if im.tt == 'LABELSYM' then
         self:error('use LA for labels')
     end
 
-    im[2] = im[2] % 0x100000000
-    if im[2] >= 0x10000 and im[2] <= 0xFFFF8000 then
+    if im.portion then
+        args.rs = 'R0'
+        args.immediate = im
+        self:format_out(addiu, args)
+        return
+    end
+
+    im.tok = im.tok % 0x100000000
+    if im.tok >= 0x10000 and im.tok <= 0xFFFF8000 then
         args.rs = args.rt
-        args.immediate = {'UPPER', im}
+        args.immediate = self:token(im):set('portion', 'upper')
         self:format_out(lui, args)
-        if im[2] % 0x10000 ~= 0 then
-            args.immediate = {'LOWER', im}
+        if im.tok % 0x10000 ~= 0 then
+            args.immediate = self:token(im):set('portion', 'lower')
             self:format_out(ori, args)
         end
-    elseif im[2] >= 0x8000 and im[2] < 0x10000 then
+    elseif im.tok >= 0x8000 and im.tok < 0x10000 then
         args.rs = 'R0'
-        args.immediate = {'LOWER', im}
+        args.immediate = self:token(im):set('portion', 'lower')
         self:format_out(ori, args)
     else
         args.rs = 'R0'
-        args.immediate = {'LOWER', im}
+        args.immediate = self:token(im):set('portion', 'lower')
         self:format_out(addiu, args)
     end
 end
@@ -50,9 +59,9 @@ function overrides.LA(self, name)
     local im = self:const()
 
     args.rs = args.rt
-    args.immediate = {'UPPEROFF', im}
+    args.immediate = self:token(im):set('portion', 'upperoff')
     self:format_out(lui, args)
-    args.immediate = {'LOWER', im}
+    args.immediate = self:token(im):set('portion', 'lower')
     self:format_out(addiu, args)
 end
 
@@ -84,14 +93,14 @@ function overrides.PUSH(self, name)
     if name == 'PUSH' then
         args.rt = 'SP'
         args.rs = 'SP'
-        args.immediate = {'NEGATE', {'NUM', #stack*4}}
+        args.immediate = self:token(#stack*4):set('negate')
         self:format_out(addi, args)
     end
     args.base = 'SP'
     for i, r in ipairs(stack) do
         args.rt = r
         if r ~= '' then
-            args.offset = {'NUM', (i - 1)*4}
+            args.offset = (i - 1)*4
             self:format_out(w, args)
         end
     end
@@ -102,7 +111,7 @@ function overrides.PUSH(self, name)
     if name == 'POP' or name == 'JPOP' then
         args.rt = 'SP'
         args.rs = 'SP'
-        args.immediate = {'NUM', #stack*4}
+        args.immediate = #stack*4
         self:format_out(addi, args)
     end
 end
@@ -175,7 +184,7 @@ function overrides.ROL(self, name)
     end
     self:format_out(sll, args)
     args.rd = 'AT'
-    args.immediate = {'NUM', 32 - args.immediate[2]}
+    args.immediate = 32 - args.immediate[2]
     self:format_out(srl, args)
     args.rd = left
     args.rs = left
@@ -202,7 +211,7 @@ function overrides.ROR(self, name)
     end
     self:format_out(srl, args)
     args.rd = 'AT'
-    args.immediate = {'NUM', 32 - args.immediate[2]}
+    args.immediate = 32 - args.immediate[2]
     self:format_out(sll, args)
     args.rd = right
     args.rs = right
@@ -238,7 +247,7 @@ function overrides.BEQI(self, name)
     self:optional_comma()
     args.immediate = self:const()
     self:optional_comma()
-    args.offset = {'SIGNED', self:const('relative')}
+    args.offset = self:token(self:const('relative')):set('signed')
 
     if reg == 'AT' then
         self:error('register cannot be AT in this pseudo-instruction')
@@ -261,7 +270,7 @@ function overrides.BLTI(self, name)
     self:optional_comma()
     args.immediate = self:const()
     self:optional_comma()
-    args.offset = {'SIGNED', self:const('relative')}
+    args.offset = self:token(self:const('relative')):set('signed')
 
     if args.rs == 'AT' then
         self:error('register cannot be AT in this pseudo-instruction')
@@ -287,7 +296,7 @@ function overrides.BLEI(self, name)
     self:optional_comma()
     args.immediate = self:const()
     self:optional_comma()
-    local offset = {'SIGNED', self:const('relative')}
+    local offset = self:token(self:const('relative')):set('signed')
 
     if reg == 'AT' then
         self:error('register cannot be AT in this pseudo-instruction')
diff --git a/Lua/lib/lips/util.lua b/Lua/lib/lips/util.lua
new file mode 100644
index 0000000..e545561
--- /dev/null
+++ b/Lua/lib/lips/util.lua
@@ -0,0 +1,37 @@
+local floor = math.floor
+local open = io.open
+
+local function Class(inherit)
+    local class = {}
+    local mt_obj = {__index = class}
+    local mt_class = {
+        __call = function(self, ...)
+            local obj = setmetatable({}, mt_obj)
+            obj:init(...)
+            return obj
+        end,
+        __index = inherit,
+    }
+
+    return setmetatable(class, mt_class)
+end
+
+local function readfile(fn)
+    local f = open(fn, 'r')
+    if not f then
+        error('could not open assembly file for reading: '..tostring(fn), 2)
+    end
+    local asm = f:read('*a')
+    f:close()
+    return asm
+end
+
+local function bitrange(x, lower, upper)
+    return floor(x/2^lower) % 2^(upper - lower + 1)
+end
+
+return {
+    Class = Class,
+    readfile = readfile,
+    bitrange = bitrange,
+}