split Preproc expansion into Expander class

lips/Expander.lua

@@ -0,0 +1,96 @@
+local insert = table.insert
+
+local path = string.gsub(..., "[^.]+$", "")
+local data = require(path.."data")
+local overrides = require(path.."overrides")
+local Statement = require(path.."Statement")
+local Reader = require(path.."Reader")
+
+local Expander = Reader:extend()
+function Expander:init(options)
+    self.options = options or {}
+end
+
+function Expander:statement(...)
+    local s = Statement(self.fn, self.line, ...)
+    return s
+end
+
+function Expander:push(s)
+    s:validate()
+    insert(self.statements, s)
+end
+
+function Expander:push_new(...)
+    self:push(self:statement(...))
+end
+
+function Expander:pop(kind)
+    local ret
+    if kind == nil then
+        ret = self.s[self.i]
+    elseif kind == 'CPU' then
+        ret = self:register(data.registers)
+    elseif kind == 'DEREF' then
+        ret = self:deref()
+    elseif kind == 'CONST' then
+        ret = self:const()
+    elseif kind == 'END' then
+        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
+        error('Internal Error: unknown kind, got '..tostring(kind))
+    end
+    self.i = self.i + 1
+    return ret
+end
+
+function Expander:expand(statements)
+    -- fourth pass: expand pseudo-instructions and register arguments
+    self.statements = {}
+    for i, s in ipairs(statements) do
+        self.s = s
+        self.fn = s.fn
+        self.line = s.line
+        if s.type:sub(1, 1) == '!' then
+            self:push(s)
+        else
+            local name = s.type
+            local h = data.instructions[name]
+            if h == nil then
+                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)
+                self:pop('END')
+            else
+                self:push(s)
+            end
+        end
+    end
+
+    return self.statements
+end
+
+return Expander

lips/Parser.lua

@@ -6,6 +6,7 @@ local Token = require(path.."Token")
 local Lexer = require(path.."Lexer")
 local Collector = require(path.."Collector")
 local Preproc = require(path.."Preproc")
+local Expander = require(path.."Expander")
 local Dumper = require(path.."Dumper")
 
 local Parser = Base:extend()
@@ -50,11 +51,10 @@ function Parser:parse(asm)
     self.statements = self:tokenize(asm)
     if self.options.debug_token then self:dump() end
 
-    local preproc = Preproc(self.options)
+    self.statements = Preproc(self.options):process(self.statements)
-    self.statements = preproc:process(self.statements)
     if self.options.debug_pre then self:dump() end
 
-    self.statements = preproc:expand(self.statements)
+    self.statements = Expander(self.options):expand(self.statements)
     if self.options.debug_post then self:dump() end
 
     local dumper = Dumper(self.writer, self.options)

lips/Preproc.lua

@@ -2,20 +2,32 @@ local abs = math.abs
 local insert = table.insert
 
 local path = string.gsub(..., "[^.]+$", "")
-local data = require(path.."data")
+local Base = require(path.."Base")
-local overrides = require(path.."overrides")
-local Statement = require(path.."Statement")
-local Reader = require(path.."Reader")
 local Expression = require(path.."Expression")
 local util = require(path.."util")
 
 local signs = util.signs
 
-local Preproc = Reader:extend()
+local Preproc = Base:extend()
 function Preproc:init(options)
     self.options = options or {}
 end
 
+function Preproc:iter(statements)
+    assert(statements)
+    local i = 0
+    return function()
+        i = i + 1
+        local s = statements[i]
+        if s == nil then return end
+        self.i = i
+        self.s = s
+        self.fn = s.fn
+        self.line = s.line
+        return s
+    end
+end
+
 function Preproc:lookup(t)
     if t.tt == 'VARSYM' then
         local name = t.tok
@@ -100,8 +112,6 @@ function Preproc:check(s, i, tt)
 end
 
 function Preproc:process(statements)
-    self.statements = statements
-
     self.variables = {}
     self.plus_labels = {} -- constructed forwards
     self.minus_labels = {} -- constructed backwards
@@ -109,11 +119,7 @@ function Preproc:process(statements)
 
     -- first pass: resolve variables and collect relative labels
     local new_statements = {}
-    for i=1, #self.statements do
+    for s in self:iter(statements) do
-        local s = self.statements[i]
-        self.fn = s.fn
-        self.line = s.line
-        if s.type:sub(1, 1) == '!' then
         -- directive, label, etc.
         if s.type == '!VAR' then
             local a = self:check(s, 1, 'VAR')
@@ -136,12 +142,6 @@ function Preproc:process(statements)
                 end
             end
             insert(new_statements, s)
-            else
-                for j, t in ipairs(s) do
-                    self:lookup(t)
-                end
-                insert(new_statements, s)
-            end
         else
             -- regular instruction
             for j, t in ipairs(s) do
@@ -153,21 +153,14 @@ function Preproc:process(statements)
 
     -- second pass: resolve relative labels
     self.do_labels = true
-    for i=1, #new_statements do
+    for s in self:iter(new_statements) do
-        self.i = i -- make visible to :lookup
-        local s = new_statements[i]
-        self.fn = s.fn
-        self.line = s.line
         for j, t in ipairs(s) do
             self:lookup(t)
         end
     end
 
     -- third pass: evaluate constant expressions
-    for i=1, #new_statements do
+    for s in self:iter(new_statements) do
-        local s = new_statements[i]
-        self.fn = s.fn
-        self.line = s.line
         for j, t in ipairs(s) do
             if t.tt == 'EXPR' then
                 local expr = Expression()
@@ -184,89 +177,4 @@ function Preproc:process(statements)
     return new_statements
 end
 
-function Preproc:statement(...)
-    self.fn = self.s.fn
-    self.line = self.s.line
-    local s = Statement(self.fn, self.line, ...)
-    return s
-end
-
-function Preproc:push(s)
-    s:validate()
-    insert(self.statements, s)
-end
-
-function Preproc:push_new(...)
-    self:push(self:statement(...))
-end
-
-function Preproc:pop(kind)
-    local ret
-    if kind == nil then
-        ret = self.s[self.i]
-    elseif kind == 'CPU' then
-        ret = self:register(data.registers)
-    elseif kind == 'DEREF' then
-        ret = self:deref()
-    elseif kind == 'CONST' then
-        ret = self:const()
-    elseif kind == 'END' then
-        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
-        error('Internal Error: unknown kind, got '..tostring(kind))
-    end
-    self.i = self.i + 1
-    return ret
-end
-
-function Preproc:expand(statements)
-    -- fourth pass: expand pseudo-instructions and register arguments
-    self.statements = {}
-    for i=1, #statements do
-        local s = statements[i]
-        self.s = s
-        self.fn = s.fn
-        self.line = s.line
-        if s.type:sub(1, 1) == '!' then
-            self:push(s)
-        else
-            local name = s.type
-            local h = data.instructions[name]
-            if h == nil then
-                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)
-                self:pop('END')
-            else
-                self:push(s)
-            end
-        end
-    end
-
-    return self.statements
-end
-
 return Preproc

lips/overrides.lua

@@ -47,7 +47,7 @@ local function li(self, buffer, dest, im)
 end
 
 local overrides = {}
--- note: "self" is an instance of Preproc
+-- note: "self" is an instance of Expander
 
 local function tob_override(self, name)
     -- handle all the addressing modes for lw/sw-like instructions