diff --git a/Lua/lib/lips/Collector.lua b/Lua/lib/lips/Collector.lua
index 3bd338d..2fb21a7 100644
--- a/Lua/lib/lips/Collector.lua
+++ b/Lua/lib/lips/Collector.lua
@@ -35,6 +35,10 @@ function Collector:push_data(datum, size)
 
     -- TODO: consider not scrunching data statements, just their tokens
 
+    if type(datum) == 'number' then
+        datum = self:token(datum)
+    end
+
     local last_statement = self.statements[#self.statements]
     local s
     if last_statement and last_statement.type == '!DATA' then
@@ -44,16 +48,25 @@ function Collector:push_data(datum, size)
         insert(self.statements, s)
     end
 
-    if type(datum) == 'string' and size == 'WORD' then
-        -- labels will be assembled to words
-        insert(s, Token('LABEL', datum))
-        return
-    end
-
     if size ~= 'BYTE' and size ~= 'HALFWORD' and size ~= 'WORD' then
         error('Internal Error: unknown data size argument')
     end
 
+    if datum.tt == 'LABELSYM' then
+        if size == 'WORD' then
+            -- labels will be assembled to words
+            insert(s, datum)
+            return
+        else
+            self:error('labels are too large to be used in this directive')
+        end
+    elseif datum.tt == 'VARSYM' then
+        insert(s, datum:set('size', size))
+        return
+    elseif datum.tt ~= 'NUM' then
+        self:error('unsupported data type', datum.tt)
+    end
+
     local sizes = size..'S'
 
     local last_token = s[#s]
@@ -65,7 +78,7 @@ function Collector:push_data(datum, size)
         insert(s, t)
         s:validate()
     end
-    insert(t.tok, datum)
+    insert(t.tok, datum.tok)
 end
 
 function Collector:variable()
@@ -85,6 +98,12 @@ function Collector:directive()
     end
     if name == 'ORG' or name == 'BASE' then
         add(name, self:const(nil, 'no labels'))
+    elseif name == 'PUSH' or name == 'POP' then
+        add(name, self:const())
+        while not self:is_EOL() do
+            self:optional_comma()
+            add(name, self:const())
+        end
     elseif name == 'ALIGN' or name == 'SKIP' then
         if self:is_EOL() and name == 'ALIGN' then
             add(name)
@@ -96,18 +115,31 @@ function Collector:directive()
                 self:optional_comma()
                 add(name, size, self:number())
             end
-            self:expect_EOL()
         end
     elseif name == 'BYTE' or name == 'HALFWORD' or name == 'WORD' then
-        self:push_data(self:const().tok, name)
+        self:push_data(self:const(), name)
         while not self:is_EOL() do
-            self:advance()
             self:optional_comma()
-            self:push_data(self:const().tok, name)
+            self:push_data(self:const(), name)
         end
-        self:expect_EOL()
+    elseif name == 'HEX' then
+        if self.tt ~= 'OPEN' then
+            self:error('expected opening brace for hex directive', self.tt)
+        end
+        self:advance()
+
+        while self.tt ~= 'CLOSE' do
+            if self.tt == 'EOL' then
+                self:advance()
+            else
+                self:push_data(self:const(), 'BYTE')
+            end
+        end
+        self:advance()
     elseif name == 'INC' or name == 'INCBIN' then
         -- noop, handled by lexer
+        self:string()
+        return -- don't expect EOL
     elseif name == 'ASCII' or name == 'ASCIIZ' then
         local bytes = self:string()
         for i, number in ipairs(bytes.tok) do
@@ -116,12 +148,12 @@ function Collector:directive()
         if name == 'ASCIIZ' then
             self:push_data(0, 'BYTE')
         end
-        self:expect_EOL()
     elseif name == 'FLOAT' then
         self:error('unimplemented directive', name)
     else
         self:error('unknown directive', name)
     end
+    self:expect_EOL()
 end
 
 function Collector:basic_special()
@@ -200,8 +232,8 @@ function Collector:collect(tokens, fn)
     self.statements = {}
 
     -- this works, but probably shouldn't be in this function specifically
-    if self.options.offset then
-        local s = Statement('(options)', 0, '!ORG', self.options.offset)
+    if self.options.origin then
+        local s = Statement('(options)', 0, '!ORG', self.options.origin)
         insert(self.statements, s)
     end
     if self.options.base then
diff --git a/Lua/lib/lips/Dumper.lua b/Lua/lib/lips/Dumper.lua
index 6a2d320..6a7c0db 100644
--- a/Lua/lib/lips/Dumper.lua
+++ b/Lua/lib/lips/Dumper.lua
@@ -1,6 +1,7 @@
 local floor = math.floor
 local format = string.format
 local insert = table.insert
+local remove = table.remove
 local unpack = unpack or table.unpack
 
 local path = string.gsub(..., "[^.]+$", "")
@@ -12,13 +13,6 @@ local Reader = require(path.."Reader")
 
 local bitrange = util.bitrange
 
-local function label_delta(from, to)
-    -- TODO: consider removing the % here since .base should handle that now
-    to = to
-    from = from
-    return floor(to/4) - 1 - floor(from/4)
-end
-
 local Dumper = Reader:extend()
 function Dumper:init(writer, options)
     self.writer = writer
@@ -41,17 +35,21 @@ function Dumper:export_labels(t)
     return t
 end
 
+function Dumper:label_delta(from, to)
+    from = from % 0x80000000
+    to = to % 0x80000000
+    local rel = floor(to/4) - 1 - floor(from/4)
+    if rel > 0x8000 or rel <= -0x8000 then
+        self:error('branch too far', rel)
+    end
+    return rel % 0x10000
+end
+
 function Dumper:desym(t)
-    if t.tt == 'REL' then
-        local rel = label_delta(self:pc(), t.tok)
-        if rel > 0x8000 or rel <= -0x8000 then
-            self:error('branch too far')
-        end
-        return rel % 0x10000
+    -- note: don't run t:compute() here; let valvar handle that
+    if t.tt == 'REL' and not t.fixed then
+        return self:label_delta(self:pc(), t.tok)
     elseif type(t.tok) == 'number' then
-        if t.offset then
-            return t.tok + t.offset
-        end
         return t.tok
     elseif t.tt == 'REG' then
         assert(data.all_registers[t.tok], 'Internal Error: unknown register')
@@ -61,18 +59,11 @@ function Dumper:desym(t)
         if label == nil then
             self:error('undefined label', t.tok)
         end
-        if t.offset then
-            label = label + t.offset
-        end
         if t.tt == 'LABELSYM' then
             return label
         end
 
-        local rel = label_delta(self:pc(), label)
-        if rel > 0x8000 or rel <= -0x8000 then
-            self:error('branch too far')
-        end
-        return rel % 0x10000
+        return self:label_delta(self:pc(), label)
     end
     error('Internal Error: failed to desym')
 end
@@ -80,7 +71,7 @@ end
 function Dumper:validate(n, bits)
     local max = 2^bits
     if n == nil then
-        self:error('value is nil') -- internal error?
+        error('Internal Error: number to validate is nil', 2)
     end
     if n > max or n < 0 then
         self:error('value out of range', ("%X"):format(n))
@@ -109,34 +100,6 @@ function Dumper:write(t)
     end
 end
 
-function Dumper:dump_instruction(t)
-    local uw = 0
-    local lw = 0
-
-    local o = t[1]
-    uw = uw + o*0x400
-
-    if #t == 2 then
-        local val = self:valvar(t[2], 26)
-        uw = uw + bitrange(val, 16, 25)
-        lw = lw + bitrange(val, 0, 15)
-    elseif #t == 4 then
-        uw = uw + self:valvar(t[2], 5)*0x20
-        uw = uw + self:valvar(t[3], 5)
-        lw = lw + self:valvar(t[4], 16)
-    elseif #t == 6 then
-        uw = uw + self:valvar(t[2], 5)*0x20
-        uw = uw + self:valvar(t[3], 5)
-        lw = lw + self:valvar(t[4], 5)*0x800
-        lw = lw + self:valvar(t[5], 5)*0x40
-        lw = lw + self:valvar(t[6], 6)
-    else
-        error('Internal Error: unknown n-size')
-    end
-
-    return uw, lw
-end
-
 function Dumper:assemble_j(first, out)
     local w = 0
     w = w + self:valvar(first,   6) * 0x04000000
@@ -172,6 +135,7 @@ function Dumper:format_in(informat)
     -- see data.lua for a guide on what all these mean
     local args = {}
     --if #informat ~= #s then error('mismatch') end
+    self.i = 0
     for i=1, #informat do
         self.i = i
         local c = informat:sub(i, i)
@@ -202,7 +166,7 @@ function Dumper:format_in(informat)
         elseif c == 'I' and not args.index then
             args.index = self:const():set('index')
         elseif c == 'k' and not args.immediate then
-            args.immediate = self:const(nil, 'no label'):set('negate')
+            args.immediate = self:const(nil, 'no label'):set('signed'):set('negate')
         elseif c == 'K' and not args.immediate then
             args.immediate = self:const(nil, 'no label'):set('signed')
         elseif c == 'b' and not args.base then
@@ -254,6 +218,9 @@ function Dumper:assemble(s)
     self.s = s
     if h[2] ~= nil then
         local args = self:format_in(h[2])
+        if self.i ~= #s then
+            self:error('expected EOL; too many arguments')
+        end
         return self:format_out(h, args)
     else
         self:error('unimplemented instruction', name)
@@ -276,6 +243,7 @@ function Dumper:pc()
 end
 
 function Dumper:load(statements)
+    local valstack = {} -- for .push/.pop directives
     local new_statements = {}
     self.pos = 0
     self.base = 0
@@ -296,13 +264,58 @@ function Dumper:load(statements)
             elseif s.type == '!BASE' then
                 self.base = s[1].tok
                 insert(new_statements, s)
+            elseif s.type == '!PUSH' or s.type == '!POP' then
+                local thistype = s.type:sub(2):lower()
+                for i, t in ipairs(s) do
+                    local name = t.tok
+                    if type(name) ~= 'string' then
+                        self:error('expected state to '..thistype, name)
+                    end
+
+                    name = name:lower()
+                    local pushing = s.type == '!PUSH'
+                    if name == 'org' then
+                        if pushing then
+                            insert(valstack, self.pos)
+                        else
+                            self.pos = remove(valstack)
+                        end
+                    elseif name == 'base' then
+                        if pushing then
+                            insert(valstack, self.base)
+                        else
+                            self.base = remove(valstack)
+                        end
+                    elseif name == 'pc' then
+                        if pushing then
+                            insert(valstack, self.pos)
+                            insert(valstack, self.base)
+                        else
+                            self.base = remove(valstack)
+                            self.pos = remove(valstack)
+                        end
+                    else
+                        self:error('unknown state to '..thistype, name)
+                    end
+
+                    if self.pos == nil or self.base == nil then
+                        self:error('ran out of values to pop')
+                    end
+
+                    if not pushing then
+                        local s = Statement(self.fn, self.line, '!ORG', self.pos)
+                        insert(new_statements, s)
+                        local s = Statement(self.fn, self.line, '!BASE', self.base)
+                        insert(new_statements, s)
+                    end
+                end
             elseif s.type == '!ALIGN' or s.type == '!SKIP' then
                 local length, content
                 if s.type == '!ALIGN' then
                     local align = s[1] and s[1].tok or 2
                     content = s[2] and s[2].tok or 0
                     if align < 0 then
-                        self:error('negative alignment')
+                        self:error('negative alignment', align)
                     else
                         align = 2^align
                     end
@@ -352,13 +365,17 @@ function Dumper:load(statements)
             insert(new_statements, new)
         elseif s.type == '!DATA' then
             for i, t in ipairs(s) do
-                if t.tt == 'LABEL' then
+                if t.tt == 'LABELSYM' then
                     local label = self.labels[t.tok]
                     if label == nil then
                         self:error('undefined label', t.tok)
                     end
                     t.tt = 'WORDS'
                     t.tok = {label}
+                elseif t.tt == 'NUM' then
+                    t.tt = t.size..'S'
+                    t.tok = {t.tok}
+                    t.size = nil
                 end
             end
             self.pos = self.pos + (s.length or util.measure_data(s))
diff --git a/Lua/lib/lips/Lexer.lua b/Lua/lib/lips/Lexer.lua
index d035991..81ee4e8 100644
--- a/Lua/lib/lips/Lexer.lua
+++ b/Lua/lib/lips/Lexer.lua
@@ -193,11 +193,13 @@ function Lexer:lex_hex(yield)
             end
             self:nextc()
             entered = true
+            yield('OPEN', '{')
         elseif self.chr == '}' then
             if not entered then
                 self:error('expected opening brace')
             end
             self:nextc()
+            yield('CLOSE', '}')
             break
         elseif self.chr == ',' then
             self:error('commas are not allowed in HEX directives')
@@ -208,7 +210,6 @@ function Lexer:lex_hex(yield)
             if self.chr:find(hexmatch) then
                 self:error('too many hex digits to be a single byte')
             end
-            yield('DIR', 'BYTE')
             yield('NUM', num)
         elseif self.chr:find(hexmatch) then
             self:error('expected two hex digits to make a byte')
@@ -248,7 +249,7 @@ function Lexer:lex_string(yield)
     local bytes = {}
     while true do
         if self.chr == '\n' then
-            self:error('unimplemented')
+            self:error('unimplemented: newlines in strings')
             yield('EOL', '\n')
             self:nextc()
         elseif self.ord == self.EOF then
@@ -294,6 +295,8 @@ function Lexer:lex_include(_yield)
     self:lex_string_naive(function(tt, tok)
         fn = tok
     end)
+    _yield('STRING', fn, self.fn, self.line)
+
     if self.options.path then
         fn = self.options.path..fn
     end
@@ -307,15 +310,18 @@ function Lexer:lex_include_binary(_yield)
     self:lex_string_naive(function(tt, tok)
         fn = tok
     end)
+    _yield('STRING', fn, self.fn, self.line)
+
     -- TODO: allow optional offset and size arguments
     if self.options.path then
         fn = self.options.path..fn
     end
-    -- FIXME: this allocates two tables for each byte.
-    --        this could easily cause performance issues on big files.
     local data = util.readfile(fn, true)
+
+    -- FIXME: this allocates a table for each byte.
+    --        this could easily cause performance issues on big files.
+    _yield('DIR', 'BYTE', fn, 0)
     for b in string.gfind(data, '.') do
-        _yield('DIR', 'BYTE', fn, 0)
         _yield('NUM', string.byte(b), fn, 0)
     end
 end
@@ -414,6 +420,7 @@ function Lexer:lex(_yield)
                 self:nextc()
                 yield('LABEL', buff)
             elseif up == 'HEX' then
+                yield('DIR', 'HEX')
                 self:lex_hex(yield)
             elseif data.all_registers[up] then
                 yield('REG', up)
diff --git a/Lua/lib/lips/Muncher.lua b/Lua/lib/lips/Muncher.lua
index b3f52fa..a9794ed 100644
--- a/Lua/lib/lips/Muncher.lua
+++ b/Lua/lib/lips/Muncher.lua
@@ -56,7 +56,7 @@ function Muncher:expect_EOL()
         self:advance()
         return
     end
-    self:error('expected end of line')
+    self:error('expected end of line', self.tt)
 end
 
 function Muncher:optional_comma()
@@ -68,7 +68,7 @@ end
 
 function Muncher:number()
     if self.tt ~= 'NUM' then
-        self:error('expected number')
+        self:error('expected number', self.tt)
     end
     local t = self.t
     self:advance()
@@ -77,7 +77,7 @@ end
 
 function Muncher:string()
     if self.tt ~= 'STRING' then
-        self:error('expected string')
+        self:error('expected string', self.tt)
     end
     local t = self.t
     self:advance()
@@ -87,11 +87,11 @@ end
 function Muncher:register(registers)
     registers = registers or data.registers
     if self.tt ~= 'REG' then
-        self:error('expected register')
+        self:error('expected register', self.tt)
     end
     local t = self.t
     if not registers[t.tok] then
-        self:error('wrong type of register')
+        self:error('wrong type of register', t.tok)
     end
     self:advance()
     return self:token(t)
@@ -99,16 +99,16 @@ end
 
 function Muncher:deref()
     if self.tt ~= 'OPEN' then
-        self:error('expected opening parenthesis for dereferencing')
+        self:error('expected opening parenthesis for dereferencing', self.tt)
     end
     self:advance()
     if self.tt ~= 'REG' then
-        self:error('expected register to dereference')
+        self:error('expected register to dereference', self.tt)
     end
     local t = self.t
     self:advance()
     if self.tt ~= 'CLOSE' then
-        self:error('expected closing parenthesis for dereferencing')
+        self:error('expected closing parenthesis for dereferencing', self.tt)
     end
     self:advance()
     return self:token(t)
@@ -119,35 +119,28 @@ function Muncher:const(relative, no_label)
         self:error('expected constant', self.tt)
     end
     if no_label and self.tt == 'LABELSYM' then
-        self:error('labels are not allowed here')
+        self:error('labels are not allowed here', self.tt)
     end
     local t = self:token(self.t)
-    if relative then
-        if self.tt == 'LABELSYM' then
-            t.tt = 'LABELREL'
-        else
-            t.tt = 'REL'
-        end
-    end
     self:advance()
     return t
 end
 
 function Muncher:special()
     if self.tt ~= 'SPECIAL' then
-        self:error('expected special name to call')
+        self:error('expected special name to call', self.tt)
     end
     local name = self.tok
     self:advance()
     if self.tt ~= 'OPEN' then
-        self:error('expected opening parenthesis for special call')
+        self:error('expected opening parenthesis for special call', self.tt)
     end
 
     local args = {}
     while true do
         local arg = self:advance()
         if not arg_types[arg.tt] then
-            self:error('invalid argument type')
+            self:error('invalid argument type', arg.tt)
         else
             self:advance()
         end
@@ -157,7 +150,7 @@ function Muncher:special()
             insert(args, arg)
             break
         else
-            self:error('unexpected token in argument list')
+            self:error('unexpected token in argument list', self.tt)
         end
     end
 
diff --git a/Lua/lib/lips/Parser.lua b/Lua/lib/lips/Parser.lua
index 78c66f6..66d2766 100644
--- a/Lua/lib/lips/Parser.lua
+++ b/Lua/lib/lips/Parser.lua
@@ -41,14 +41,25 @@ function Parser:tokenize(asm)
 end
 
 function Parser:debug_dump()
+    local boring = {
+        tt = true,
+        tok = true,
+        fn = true,
+        line = true,
+    }
     for i, s in ipairs(self.statements) do
         local values = ''
-        for j, v in ipairs(s) do
-            local tok = v.tok
+        for j, t in ipairs(s) do
+            local tok = t.tok
             if type(tok) == 'number' then
                 tok = ("$%X"):format(tok)
             end
-            values = values..'\t'..v.tt..'('..tostring(tok)..')'
+            values = values..'\t'..t.tt..'('..tostring(tok)..')'
+            for k, v in pairs(t) do
+                if not boring[k] then
+                    values = values..'['..k..'='..tostring(v)..']'
+                end
+            end
         end
         values = values:sub(2)
         print(s.line, s.type, values)
@@ -62,14 +73,17 @@ function Parser:parse(asm)
 
     local preproc = Preproc(self.options)
     self.statements = preproc:process(self.statements)
-    self.statements = preproc:expand(self.statements)
 
     if self.options.debug_pre then self:debug_dump() end
 
+    self.statements = preproc:expand(self.statements)
+
+    if self.options.debug_post then self:debug_dump() end
+
     local dumper = Dumper(self.writer, self.options)
     self.statements = dumper:load(self.statements)
 
-    if self.options.debug_dump then self:debug_dump() end
+    if self.options.debug_asm then self:debug_dump() end
 
     if self.options.labels then
         dumper:export_labels(self.options.labels)
diff --git a/Lua/lib/lips/Preproc.lua b/Lua/lib/lips/Preproc.lua
index 7a09e22..ab68da2 100644
--- a/Lua/lib/lips/Preproc.lua
+++ b/Lua/lib/lips/Preproc.lua
@@ -90,7 +90,8 @@ function Preproc:check(s, i, tt)
     i = i or self.i
     local t = s[i]
     if t == nil then
-        self:error("expected another argument")
+        local err = ("expected another argument for %s at position %i"):format(self.s.type, self.i)
+        self:error(err)
     end
 
     self.fn = t.fn
@@ -197,11 +198,9 @@ function Preproc:pop(kind)
         ret = self:deref()
     elseif kind == 'CONST' then
         ret = self:const()
-    elseif kind == 'REL' then
-        ret = self:const('REL')
     elseif kind == 'END' then
-        if self.s[self.i + 1] ~= nil then
-            self:error('too many arguments')
+        if self.s[self.i] ~= nil then
+            self:error('expected EOL; too many arguments')
         end
         return -- don't increment self.i past end of arguments
     else
@@ -212,7 +211,7 @@ function Preproc:pop(kind)
 end
 
 function Preproc:expand(statements)
-    -- third pass: expand pseudo-instructions
+    -- third pass: expand pseudo-instructions and register arguments
     self.statements = {}
     for i=1, #statements do
         local s = statements[i]
@@ -228,6 +227,23 @@ function Preproc:expand(statements)
                 error('Internal Error: unknown instruction')
             end
 
+            if data.one_register_variants[name] then
+                self.i = 1
+                local a = self:register(data.all_registers)
+                local b = s[2]
+                if b == nil or b.tt ~= 'REG' then
+                    insert(s, 2, self:token(a))
+                end
+            elseif data.two_register_variants[name] then
+                self.i = 1
+                local a = self:register(data.all_registers)
+                local b = self:register(data.all_registers)
+                local c = s[3]
+                if c == nil or c.tt ~= 'REG' then
+                    insert(s, 2, self:token(a))
+                end
+            end
+
             if overrides[name] then
                 self.i = 1
                 overrides[name](self, name)
diff --git a/Lua/lib/lips/Reader.lua b/Lua/lib/lips/Reader.lua
index 8c31484..ca1468a 100644
--- a/Lua/lib/lips/Reader.lua
+++ b/Lua/lib/lips/Reader.lua
@@ -27,7 +27,8 @@ end
 function Reader:expect(tts)
     local t = self.s[self.i]
     if t == nil then
-        self:error("expected another argument") -- TODO: more verbose
+        local err = ("expected another argument for %s at position %i"):format(self.s.type, self.i)
+        self:error(err)
     end
 
     self.fn = t.fn
@@ -39,8 +40,12 @@ function Reader:expect(tts)
         end
     end
 
-    --local err = ("argument %i of %s expected type %s"):format(self.i, self.s.type, tt)
-    local err = ("unexpected type for argument %i of %s"):format(self.i, self.s.type)
+    local err
+    if #tts == 1 then
+        err = ("argument %i of %s expected type %s"):format(self.i, self.s.type, tts[1])
+    else
+        err = ("unexpected type for argument %i of %s"):format(self.i, self.s.type)
+    end
     self:error(err, t.tt)
 end
 
@@ -49,7 +54,7 @@ function Reader:register(registers)
     local t = self.s[self.i]
     local numeric = registers[t.tok]
     if not numeric then
-        self:error('wrong type of register')
+        self:error('wrong type of register', t.tok)
     end
     local new = Token(t)
     return new
@@ -63,7 +68,7 @@ function Reader:const(relative, no_label)
         self:expect{'NUM', 'LABELREL'}
     end
     local new = Token(t)
-    if relative then
+    if relative then -- you probably shouldn't use this in Preproc
         if t.tt == 'LABELSYM' then
             new.tt = 'LABELREL'
         elseif t.tt == 'NUM' then
diff --git a/Lua/lib/lips/Token.lua b/Lua/lib/lips/Token.lua
index 482b9f8..1911034 100644
--- a/Lua/lib/lips/Token.lua
+++ b/Lua/lib/lips/Token.lua
@@ -68,11 +68,15 @@ function Token:set(key, value)
     return self
 end
 
-function Token:compute()
-    assert(self.tt == 'NUM', 'Internal Error: cannot compute a non-number token')
-    local n = self.tok
+function Token:compute(n)
+    local n = n or self.tok
+    assert(n or self.tt == 'NUM', 'Internal Error: cannot compute a non-number token')
+
+    if self.offset then
+        n = n + self.offset
+    end
+
     if self.index then
-        -- TODO: should this still be here now that we have .base?
         n = n % 0x80000000
         n = floor(n/4)
     end
@@ -94,7 +98,7 @@ function Token:compute()
         n = upper
     end
 
-    if self.negate or self.signed then
+    if self.signed then
         if n >= 0x10000 or n < -0x8000 then
             return n, 'value out of range'
         end
diff --git a/Lua/lib/lips/data.lua b/Lua/lib/lips/data.lua
index b693848..079df18 100644
--- a/Lua/lib/lips/data.lua
+++ b/Lua/lib/lips/data.lua
@@ -30,6 +30,7 @@ data.fpu_registers = {
 
 data.all_directives = {
     'ORG', 'BASE', 'ALIGN', 'SKIP',
+    'PUSH', 'POP', -- experimental
     'ASCII', 'ASCIIZ',
     'BYTE', 'HALFWORD', 'WORD',
     --'HEX', -- excluded here due to different syntax
@@ -85,7 +86,13 @@ data.fmt_double = 17
 data.fmt_word = 20
 data.fmt_long = 21
 
+-- set up dummy values for pseudo-instructions later
 local __ = {}
+-- instructions with the first two arguments as registers, but not the third
+local o1 = {}
+-- instructions with all three arguments as registers
+local o2 = {}
+
 data.instructions = {
     --[[
     data guide:
@@ -247,6 +254,7 @@ data.instructions = {
 
     -- coprocessor-related instructions
 
+    -- TODO: these can take a code value
     TEQ     = {0, 'st', 'st00C', 52},
     TGE     = {0, 'st', 'st00C', 48},
     TGEU    = {0, 'st', 'st00C', 49},
@@ -279,6 +287,7 @@ data.instructions = {
     CACHE   = {47, 'iob', 'bio'},
 
     -- misuses 'F' to write the initial bit
+--  RFE     = {16, '', 'F000C', 16, 16},
     ERET    = {16, '', 'F000C', 24, 16},
     TLBP    = {16, '', 'F000C',  8, 16},
     TLBR    = {16, '', 'F000C',  1, 16},
@@ -380,8 +389,11 @@ data.instructions = {
     CL      = { 0, 'd', '00d0C', 37},   -- OR RD, R0, R0
     MOV     = { 0, 'ds', 's0d0C', 37},  -- OR RD, RS, R0
     NEG     = { 0, 'dt', '0td0C', 34},  -- SUB RD, R0, RT
+    NEGU    = { 0, 'dt', '0td0C', 35},  -- SUBU RD, R0, RT
     NOP     = { 0, '', '0'},            -- SLL R0, R0, 0
     NOT     = { 0, 'ds', 's0d0C', 39},  -- NOR RD, RS, R0
+    SGT     = { 0, 'dst', 'tsd0C', 42}, -- SLT RD, RT, RS
+    SGTU    = { 0, 'dst', 'tsd0C', 43}, -- SLTU RD, RT, RS
     SUBI    = { 8, 'tsk', 'sti'},       -- ADDI RT, RS, -immediate
     SUBIU   = { 9, 'tsk', 'sti'},       -- ADDIU RT, RS, -immediate
 
@@ -393,41 +405,95 @@ data.instructions = {
     PUSH    = __,
     POP     = __,
     JPOP    = __,
+--  CL      = __, overridden to take varargs
 
-    ABS     = __, -- BGEZ NOP SUBU?
-    MUL     = __, -- MULT MFLO
-    --DIV     = __, -- 3 arguments
-    REM     = __, -- 3 arguments
+    ABS     = o1, -- SRA XOR SUBU
+    MUL     = o2, -- MULT MFLO
+--  DIV     = o2, -- 3 arguments
+    REM     = o2, -- 3 arguments
 
-    NAND    = __, -- AND, NOT
-    NANDI   = __, -- ANDI, NOT
-    NORI    = __, -- ORI, NOT
-    ROL     = __, -- SLL, SRL, OR
-    ROR     = __, -- SRL, SLL, OR
+    NAND    = o2, -- AND, NOT
+    NANDI   = o1, -- ANDI, NOT
+    NORI    = o1, -- ORI, NOT
+    ROL     = o1, -- SLL, SRL, OR
+    ROR     = o1, -- SRL, SLL, OR
 
-    SEQ     = __, SEQI    = __, SEQIU   = __, SEQU    = __,
-    SGE     = __, SGEI    = __, SGEIU   = __, SGEU    = __,
-    SGT     = __, SGTI    = __, SGTIU   = __, SGTU    = __,
-    SLE     = __, SLEI    = __, SLEIU   = __, SLEU    = __,
-    SNE     = __, SNEI    = __, SNEIU   = __, SNEU    = __,
+    SEQ     = o2,
+    SGE     = o2, SGEU    = o2,
+    SLE     = o2, SLEU    = o2,
+    SNE     = o2,
 
-    BGE     = __,
-    BLE     = __,
-    BLT     = __,
-    BGT     = __,
+    SEQI    = o1, SEQIU   = o1,
+    SGEI    = o1, SGEIU   = o1,
+    SGTI    = o1, SGTIU   = o1,
+    SLEI    = o1, SLEIU   = o1,
+    SNEI    = o1, SNEIU   = o1,
+
+    BGE     = o1, BGEU    = o1,
+    BLE     = o1, BLEU    = o1,
+    BLT     = o1, BLTU    = o1,
+    BGT     = o1, BGTU    = o1,
 
     BEQI    = __, BEQIL   = __,
-    BNEI    = __, BNEIL   = __,
     BGEI    = __, BGEIL   = __,
+    BGTI    = __, BGTIL   = __,
     BLEI    = __, BLEIL   = __,
     BLTI    = __, BLTIL   = __,
-    BGTI    = __, BGTIL   = __,
+    BNEI    = __, BNEIL   = __,
+
+    BGEL    = o1, BGEUL   = o1,
+    BGTL    = o1, BGTUL   = o1,
+    BLEL    = o1, BLEUL   = o1,
+    BLTL    = o1, BLTUL   = o1,
+
 }
 
+local register_types = {
+    d = 0,
+    s = 0,
+    t = 0,
+    D = 1,
+    S = 1,
+    T = 1,
+    X = 2,
+    Y = 2,
+    Z = 2,
+}
+
+data.one_register_variants = {}
+data.two_register_variants = {}
+
 data.all_instructions = {}
 local i = 1
 for k, v in pairs(data.instructions) do
-    data.all_instructions[k:gsub('_', '.')] = i
+    local name = k:gsub('_', '.')
+
+    -- if the first two args of an instructions are the same register type,
+    -- allow it to be used with just one argument to cover both.
+    -- likewise, if all three arguments are registers of the same type,
+    -- allow just two to be used.
+    local fmt = v[2]
+    if fmt then
+        local a = fmt:sub(1, 1)
+        local b = fmt:sub(2, 2)
+        local c = fmt:sub(3, 3)
+        a = register_types[a]
+        b = register_types[b]
+        c = register_types[c]
+        if a ~= nil and b ~= nil and a == b then
+            if c == nil then
+                data.one_register_variants[name] = true
+            elseif c == a then
+                data.two_register_variants[name] = true
+            end
+        end
+    elseif v == o1 then
+        data.one_register_variants[name] = true
+    elseif v == o2 then
+        data.two_register_variants[name] = true
+    end
+
+    data.all_instructions[name] = i
     i = i + 1
 end
 revtable(data.all_instructions)
diff --git a/Lua/lib/lips/init.lua b/Lua/lib/lips/init.lua
index 9e823b7..f7f6242 100644
--- a/Lua/lib/lips/init.lua
+++ b/Lua/lib/lips/init.lua
@@ -53,6 +53,7 @@ function lips.assemble(fn_or_asm, writer, options)
             options.origin = options.offset
             options.base = 0
         else
+            options.origin = options.origin or 0
             options.base = options.base or 0x80000000
         end
 
diff --git a/Lua/lib/lips/overrides.lua b/Lua/lib/lips/overrides.lua
index 55f231d..7cdc7a5 100644
--- a/Lua/lib/lips/overrides.lua
+++ b/Lua/lib/lips/overrides.lua
@@ -8,7 +8,7 @@ local overrides = {}
 
 local function tob_override(self, name)
     -- handle all the addressing modes for lw/sw-like instructions
-    local rt = self:pop('CPU')
+    local dest = self:pop('CPU')
     local offset, base
     if self:peek('DEREF') then
         offset = 0
@@ -28,12 +28,12 @@ local function tob_override(self, name)
         end
         -- attempt to use the fewest possible instructions for this offset
         if not o.portion and (o.tt == 'LABELSYM' or o.tok >= 0x80000000) then
-            local immediate = self:token(o):set('portion', 'upperoff')
-            self:push_new('LUI', 'AT', immediate)
+            local temp = self:token(o):set('portion', 'upperoff')
+            self:push_new('LUI', 'AT', temp)
             if self.s[self.i] ~= nil then
                 local reg = self:pop('DEREF'):set('tt', 'REG')
                 if reg.tok ~= 'R0' then
-                    self:push_new('ADDU', 'AT', 'AT', 'R0')
+                    self:push_new('ADDU', 'AT', 'AT', reg)
                 end
             end
             base = self:token('DEREF', 'AT')
@@ -41,7 +41,7 @@ local function tob_override(self, name)
             base = self:pop('DEREF')
         end
     end
-    self:push_new(name, rt, offset, base)
+    self:push_new(name, dest, offset, base)
 end
 
 for k, v in pairs(data.instructions) do
@@ -50,8 +50,8 @@ for k, v in pairs(data.instructions) do
     end
 end
 
-function overrides.LI(self, name)
-    local rt = self:pop('CPU')
+function overrides:LI(name)
+    local dest = self:pop('CPU')
     local im = self:pop('CONST')
 
     -- for us, this is just semantics. for a "real" assembler,
@@ -62,40 +62,38 @@ function overrides.LI(self, name)
 
     if im.portion then
         -- FIXME: use appropriate instruction based on portion?
-        self:push_new('ADDIU', rt, 'R0', im)
+        self:push_new('ADDIU', dest, 'R0', im)
         return
     end
 
     im.tok = im.tok % 0x100000000
     if im.tok >= 0x10000 and im.tok <= 0xFFFF8000 then
-        local rs = rt
-        local immediate = self:token(im):set('portion', 'upper')
-        self:push_new('LUI', rt, immediate)
+        local temp = self:token(im):set('portion', 'upper')
+        self:push_new('LUI', dest, temp)
         if im.tok % 0x10000 ~= 0 then
-            local immediate = self:token(im):set('portion', 'lower')
-            self:push_new('ORI', rt, rs, immediate)
+            local temp = self:token(im):set('portion', 'lower')
+            self:push_new('ORI', dest, dest, temp)
         end
     elseif im.tok >= 0x8000 and im.tok < 0x10000 then
-        local immediate = self:token(im):set('portion', 'lower')
-        self:push_new('ORI', rt, 'R0', immediate)
+        local temp = self:token(im):set('portion', 'lower')
+        self:push_new('ORI', dest, 'R0', temp)
     else
-        local immediate = self:token(im):set('portion', 'lower')
-        self:push_new('ADDIU', rt, 'R0', immediate)
+        local temp = self:token(im):set('portion', 'lower')
+        self:push_new('ADDIU', dest, 'R0', temp)
     end
 end
 
-function overrides.LA(self, name)
-    local rt = self:pop('CPU')
+function overrides:LA(name)
+    local dest = self:pop('CPU')
     local im = self:pop('CONST')
 
-    local rs = rt
-    local immediate = self:token(im):set('portion', 'upperoff')
-    self:push_new('LUI', rt, immediate)
-    local immediate = self:token(im):set('portion', 'lower')
-    self:push_new('ADDIU', rt, rt, immediate)
+    local im = self:token(im):set('portion', 'upperoff')
+    self:push_new('LUI', dest, im)
+    local im = self:token(im):set('portion', 'lower')
+    self:push_new('ADDIU', dest, dest, im)
 end
 
-function overrides.PUSH(self, name)
+function overrides:PUSH(name)
     local w = name == 'PUSH' and 'SW' or 'LW'
     local stack = {}
     for _, t in ipairs(self.s) do
@@ -115,8 +113,8 @@ function overrides.PUSH(self, name)
         self:error(name..' requires at least one argument')
     end
     if name == 'PUSH' then
-        local immediate = self:token(#stack*4):set('negate')
-        self:push_new('ADDIU', 'SP', 'SP', immediate)
+        local im = self:token(#stack*4):set('negate')
+        self:push_new('ADDIU', 'SP', 'SP', im)
     end
     for i, r in ipairs(stack) do
         if r ~= '' then
@@ -128,65 +126,76 @@ function overrides.PUSH(self, name)
         self:push_new('JR', 'RA')
     end
     if name == 'POP' or name == 'JPOP' then
-        local immediate = #stack * 4
-        self:push_new('ADDIU', 'SP', 'SP', immediate)
+        local im = #stack * 4
+        self:push_new('ADDIU', 'SP', 'SP', im)
     end
 end
 overrides.POP = overrides.PUSH
 overrides.JPOP = overrides.PUSH
 
-function overrides.NAND(self, name)
-    local rd = self:pop('CPU')
-    local rs = self:pop('CPU')
-    local rt = self:pop('CPU')
-    self:push_new('AND', rd, rs, rt)
-    local rs = rd
-    local rt = 'R0'
-    self:push_new('NOR', rd, rs, rt)
+function overrides:NAND(name)
+    local dest = self:pop('CPU')
+    local src = self:pop('CPU')
+    local target = self:pop('CPU')
+    self:push_new('AND', dest, src, target)
+    self:push_new('NOR', dest, dest, 'R0') -- NOT
 end
 
-function overrides.NANDI(self, name)
-    local rt = self:pop('CPU')
-    local rs = self:pop('CPU')
-    local immediate = self:pop('CONST')
-    self:push_new('ANDI', rt, rs, immediate)
-    local rd = rt
-    local rs = rt
-    local rt = 'R0'
-    self:push_new('NOR', rd, rs, rt)
+function overrides:NANDI(name)
+    local dest = self:pop('CPU')
+    local src = self:pop('CPU')
+    local im = self:pop('CONST')
+    self:push_new('ANDI', dest, src, im)
+    self:push_new('NOR', dest, dest, 'R0') -- NOT
 end
 
-function overrides.NORI(self, name)
-    local rt = self:pop('CPU')
-    local rs = self:pop('CPU')
-    local immediate = self:pop('CONST')
-    self:push_new('ORI', rt, rs, immediate)
-    local rd = rt
-    local rs = rt
-    local rt = 'R0'
-    self:push_new('NOR', rd, rs, rt)
+function overrides:NORI(name)
+    local dest = self:pop('CPU')
+    local src = self:pop('CPU')
+    local im = self:pop('CONST')
+    self:push_new('ORI', dest, src, im)
+    self:push_new('NOR', dest, dest, 'R0') -- NOT
 end
 
-function overrides.ROL(self, name)
-    -- FIXME
-    local rd, rs, rt
-    local left = self:pop('CPU')
-    rt = self:pop('CPU')
-    local immediate = self:pop('CONST')
-    error('Internal Error: unimplemented')
+function overrides:ROL(name)
+    local first = name == 'ROL' and 'SLL' or 'SRL'
+    local second = name == 'ROL' and 'SRL' or 'SLL'
+    local dest = self:pop('CPU')
+    local src = self:pop('CPU')
+    local im = self:pop('CONST')
+    if dest == 'AT' or src == 'AT' then
+        self:error('registers cannot be AT in this pseudo-instruction')
+    end
+
+    self:push_new(first, dest, src, im)
+    local temp, err = im:compute()
+    if err then
+        self:error(err, temp)
+    end
+    self:push_new(second, 'AT', src, 32 - temp)
+    self:push_new('OR', dest, dest, 'AT')
+end
+overrides.ROR = overrides.ROL
+
+function overrides:ABS(name)
+    local dest = self:pop('CPU')
+    local src = self:pop('CPU')
+    self:push_new('SRA', 'AT', src, 31)
+    self:push_new('XOR', dest, src, 'AT')
+    self:push_new('SUBU', dest, dest, 'AT')
 end
 
-function overrides.ROR(self, name)
-    -- FIXME
-    local right = self:pop('CPU')
-    local rt = self:pop('CPU')
-    local immediate = self:pop('CONST')
-    error('Internal Error: unimplemented')
+function overrides:CL(name)
+    self:expect{'REG'} -- assert there's at least one argument
+    for i=1, #self.s do
+        local reg = self:pop('CPU')
+        self:push_new('CL', reg)
+    end
 end
 
-function overrides.JR(self, name)
-    local rs = self:peek() and self:pop('CPU') or 'RA'
-    self:push_new('JR', rs)
+function overrides:JR(name)
+    local src = self:peek() and self:pop('CPU') or 'RA'
+    self:push_new('JR', src)
 end
 
 local branch_basics = {
@@ -204,17 +213,17 @@ local branch_basics = {
     BNEIL = 'BNEL',
 }
 
-function overrides.BEQI(self, name)
+function overrides:BEQI(name)
     local branch = branch_basics[name]
     local reg = self:pop('CPU')
-    local immediate = self:pop('CONST')
-    local offset = self:pop('REL'):set('signed')
+    local im = self:pop('CONST')
+    local offset = self:pop('CONST')
 
     if reg == 'AT' then
         self:error('register cannot be AT in this pseudo-instruction')
     end
 
-    self:push_new('ADDIU', 'AT', 'R0', immediate)
+    self:push_new('ADDIU', 'AT', 'R0', im)
 
     self:push_new(branch, reg, 'AT', offset)
 end
@@ -222,17 +231,17 @@ overrides.BNEI = overrides.BEQI
 overrides.BEQIL = overrides.BEQI
 overrides.BNEIL = overrides.BEQI
 
-function overrides.BLTI(self, name)
+function overrides:BLTI(name)
     local branch = branch_basics[name]
     local reg = self:pop('CPU')
-    local immediate = self:pop('CONST')
-    local offset = self:pop('REL'):set('signed')
+    local im = self:pop('CONST')
+    local offset = self:pop('CONST')
 
     if reg == 'AT' then
         self:error('register cannot be AT in this pseudo-instruction')
     end
 
-    self:push_new('SLTI', 'AT', reg, immediate)
+    self:push_new('SLTI', 'AT', reg, im)
 
     self:push_new(branch, 'R0', 'AT', offset)
 end
@@ -240,29 +249,32 @@ overrides.BGEI = overrides.BLTI
 overrides.BLTIL = overrides.BLTI
 overrides.BGEIL = overrides.BLTI
 
-function overrides.BLEI(self, name)
+function overrides:BLEI(name)
     -- TODO: this can probably be optimized
+    if name:sub(#name) == 'L' then
+        self:error('unimplemented pseudo-instruction', name)
+    end
     local branch = branch_basics[name]
     local reg = self:pop('CPU')
-    local immediate = self:pop('CONST')
-    local offset = self:pop('REL'):set('signed')
+    local im = self:pop('CONST')
+    local offset = self:pop('CONST')
 
     if reg == 'AT' then
         self:error('register cannot be AT in this pseudo-instruction')
     end
 
-    self:push_new('ADDIU', 'AT', 'R0', immediate)
+    self:push_new('ADDIU', 'AT', 'R0', im)
 
     local beq_offset
-    if name == 'BLEI' then
+    if name == 'BLEI' or name =='BLEIL' then
         beq_offset = offset
     else
-        -- FIXME: this probably isn't correct for branch-likely instructions
-        beq_offset = 2 -- branch to delay slot of the next branch
+        -- branch to delay slot of the next branch
+        beq_offset = self:token('NUM', 2):set('fixed')
     end
-    self:push_new('BEQ', reg, 'R0', beq_offset)
+    self:push_new('BEQ', reg, 'AT', beq_offset)
 
-    self:push_new('SLT', 'AT', reg, immediate)
+    self:push_new('SLT', 'AT', reg, 'AT')
 
     self:push_new(branch, 'AT', 'R0', offset)
 end
diff --git a/Lua/lib/lips/util.lua b/Lua/lib/lips/util.lua
index 4b80607..145ecca 100644
--- a/Lua/lib/lips/util.lua
+++ b/Lua/lib/lips/util.lua
@@ -39,12 +39,27 @@ else -- 5.2, 5.3
     end
 end
 
+local data_sizes = {
+    BYTE = 1,
+    HALFWORD = 2,
+    WORD = 4,
+}
+
 local function measure_data(s)
     assert(s and s.type == '!DATA', 'Internal Error: expected !DATA statement')
     local n = 0
     for i, t in ipairs(s) do
-        if t.tt == 'LABEL' then
+        if t.tt == 'LABELSYM' then
             n = n + 4
+        elseif t.tt == 'NUM' then
+            if t.size == nil then
+                error('Internal Error: unspecified data size in NUM')
+            end
+            local size = data_sizes[t.size]
+            if size == nil then
+                error('Internal Error: unknown data size in NUM, got '..tostring(t.size))
+            end
+            n = n + size
         elseif t.tt == 'WORDS' then
             n = n + #t.tok * 4
         elseif t.tt == 'HALFWORDS' then
@@ -52,7 +67,7 @@ local function measure_data(s)
         elseif t.tt == 'BYTES' then
             n = n + #t.tok * 1
         else
-            error('Internal Error: unknown data type in !DATA')
+            error('Internal Error: unknown data type in !DATA, got '..tostring(t.tt))
         end
     end
     return n