diff --git a/constants.lua b/constants.lua
index b6ce861..d7e72f2 100644
--- a/constants.lua
+++ b/constants.lua
@@ -206,6 +206,8 @@ constants.blockOpcodes = {
 -- Types are represented as an array where each element represents an operand:
 -- * "b": byte
 -- * "u": u32
+-- * "d": u32 index (needs to be incremented by 1 to account for lua 1-indexed arrays)
+--        (used for all index types except label indices, and _not_ memory offsets)
 -- * "U": u64
 -- * "i": i32
 -- * "I": i64
@@ -219,15 +221,15 @@ constants.operandTypes = {
     [c.OP_BR] = {"u"},
     [c.OP_BR_IF] = {"u"},
     [c.OP_BR_TABLE] = {"Vu", "u"},
-    [c.OP_CALL] = {"u"},
-    [c.OP_CALL_INDIRECT] = {"u", "b"},
+    [c.OP_CALL] = {"d"},
+    [c.OP_CALL_INDIRECT] = {"d", "b"},
 -- parametric
 -- variable
-    [c.OP_LOCAL_GET] = {"u"},
-    [c.OP_LOCAL_SET] = {"u"},
-    [c.OP_LOCAL_TEE] = {"u"},
-    [c.OP_GLOBAL_GET] = {"u"},
-    [c.OP_GLOBAL_SET] = {"u"},
+    [c.OP_LOCAL_GET] = {"d"},
+    [c.OP_LOCAL_SET] = {"d"},
+    [c.OP_LOCAL_TEE] = {"d"},
+    [c.OP_GLOBAL_GET] = {"d"},
+    [c.OP_GLOBAL_SET] = {"d"},
 -- memory
     [c.OP_I32_LOAD] = {"u", "u"},
     [c.OP_I64_LOAD] = {"u", "u"},
diff --git a/strutil.lua b/strutil.lua
new file mode 100644
index 0000000..64b3435
--- /dev/null
+++ b/strutil.lua
@@ -0,0 +1,7 @@
+local strutil = {}
+
+function strutil.bytestostr(bytes, idx, len)
+    return string.char(table.unpack(bytes, idx, idx + len - 1))
+end
+
+return strutil
\ No newline at end of file
diff --git a/wasmlib.lua b/wasmlib.lua
index 4a5dcf5..0b4de4f 100644
--- a/wasmlib.lua
+++ b/wasmlib.lua
@@ -6,8 +6,10 @@ local frame = require("frame")
 local memory = require("memory")
 local intutil = require("intutil")
 local fileutil = require("fileutil")
+local strutil = require("strutil")
 
 wasmlib.VM = {
+    numImportedFuncs = 0,
     stack = {},
     stackFrames = {},
     labelStack = {},
@@ -15,6 +17,7 @@ wasmlib.VM = {
     types = {},
     memory = {},
     globals = {},
+    imports = {},
 }
 
 function wasmlib.VM:new()
@@ -413,6 +416,11 @@ function wasmlib.VM:br_table()
 end
 
 function wasmlib.VM:step()
+    if self:curFrame().pc >= #self:curBody() then
+        self:ret()
+        return
+    end
+
     local opcode = self:nextArg()
 
     local c = constants.opcodes
@@ -569,7 +577,7 @@ local function checkVersion(bytes, idx)
     return idx + 4
 end
 
-function wasmlib.VM:parseCustom(bytes, idx)
+function wasmlib.VM:parseCustom(bytes, idx) -- luacheck: no unused args
     -- ignore custom sections
     local szlen, size = intutil.fromuleb128(bytes, idx)
     return idx + szlen + size
@@ -612,10 +620,45 @@ function wasmlib.VM:parseTypes(bytes, idx)
     return idx
 end
 
-function wasmlib.VM:parseImports(bytes, idx) -- TODO
-    print("warning: skipping imports section")
-    local szlen, size = intutil.fromuleb128(bytes, idx)
-    return idx + szlen + size
+function wasmlib.VM:parseImports(bytes, idx, imports)
+    local szlen, _ = intutil.fromuleb128(bytes, idx)
+    idx = idx + szlen
+    local nilen, numImports = intutil.fromuleb128(bytes, idx)
+    idx = idx + nilen
+
+    for _ = 1, numImports do
+        local mnllen, mnameLen = intutil.fromuleb128(bytes, idx)
+        idx = idx + mnllen
+        local moduleName = strutil.bytestostr(bytes, idx, mnameLen)
+        idx = idx + mnameLen
+        local nllen, nameLen = intutil.fromuleb128(bytes, idx)
+        idx = idx + nllen
+        local importName = strutil.bytestostr(bytes, idx, nameLen)
+        idx = idx + nameLen
+
+        local importType = bytes[idx]
+        idx = idx + 1
+
+        if importType == 0x00 then
+            local typeidx = bytes[idx]
+            idx = idx + 1
+            table.insert(self.functions, {
+                typeidx = typeidx + 1,
+                import = imports[moduleName][importName],
+            })
+        elseif importType == 0x01 then
+            error("table imports not supported")
+        elseif importType == 0x02 then
+            error("memory imports not supported")
+        elseif importType == 0x03 then
+            error("global imports not supported")
+        else
+            error("invalid import type "..importType)
+        end
+    end
+
+    self.numImportedFuncs = #self.functions
+    return idx
 end
 
 function wasmlib.VM:parseFunctions(bytes, idx)
@@ -624,16 +667,16 @@ function wasmlib.VM:parseFunctions(bytes, idx)
     local nflen, numFuncs = intutil.fromuleb128(bytes, idx)
     idx = idx + nflen
 
-    for i = 1, numFuncs do -- TODO handle imported functions
+    for i = self.numImportedFuncs + 1, self.numImportedFuncs + numFuncs do
         local tilen, typeidx = intutil.fromuleb128(bytes, idx)
         idx = idx + tilen
-        self.functions[i] = { typeidx = typeidx }
+        self.functions[i] = { typeidx = typeidx + 1 }
     end
 
     return idx
 end
 
-function wasmlib.VM:parseTables(bytes, idx) -- TODO
+function wasmlib.VM:parseTables(bytes, idx, imports) -- luacheck: no unused args
     print("warning: skipping tables section")
     local szlen, size = intutil.fromuleb128(bytes, idx)
     return idx + szlen + size
@@ -708,31 +751,31 @@ function wasmlib.VM:parseGlobals(bytes, idx)
     return idx
 end
 
-function wasmlib.VM:parseExports(bytes, idx) -- TODO
+function wasmlib.VM:parseExports(bytes, idx) -- luacheck: no unused args
     print("warning: skipping exports section")
     local szlen, size = intutil.fromuleb128(bytes, idx)
     return idx + szlen + size
 end
 
-function wasmlib.VM:parseStart(bytes, idx) -- TODO
+function wasmlib.VM:parseStart(bytes, idx) -- luacheck: no unused args
     print("warning: skipping start section")
     local szlen, size = intutil.fromuleb128(bytes, idx)
     return idx + szlen + size
 end
 
-function wasmlib.VM:parseElements(bytes, idx) -- TODO
+function wasmlib.VM:parseElements(bytes, idx) -- luacheck: no unused args
     print("warning: skipping elements section")
     local szlen, size = intutil.fromuleb128(bytes, idx)
     return idx + szlen + size
 end
 
-function wasmlib.VM:parseCode(bytes, idx) -- TODO
+function wasmlib.VM:parseCode(bytes, idx)
     local szlen, _ = intutil.fromuleb128(bytes, idx)
     idx = idx + szlen
     local nclen, numCode = intutil.fromuleb128(bytes, idx)
     idx = idx + nclen
 
-    for i = 1, numCode do -- TODO handle imported functions
+    for i = self.numImportedFuncs + 1, self.numImportedFuncs + numCode do
         -- size (ignored, not needed for decoding)
         local cszlen, _ = intutil.fromuleb128(bytes, idx)
         idx = idx + cszlen
@@ -776,14 +819,15 @@ function wasmlib.VM:parseCode(bytes, idx) -- TODO
             end
 
             local operands = constants.operandTypes[opcode] or {}
-            for _ = 1, #operands do
-                local operand = operands[i]
+            for j = 1, #operands do
+                local operand = operands[j]
                 if operand == "b" then
                     local a = bytes[idx]
                     idx = idx + 1
                     table.insert(body, a)
-                elseif operand == "u" or operand == "U" then
+                elseif operand == "u" or operand == "U" or operand == "d" then
                     local alen, a = intutil.fromuleb128(bytes, idx)
+                    if operand == "d" then a = a + 1 end
                     idx = idx + alen
                     table.insert(body, a)
                 elseif operand == "i" then
@@ -812,12 +856,13 @@ function wasmlib.VM:parseCode(bytes, idx) -- TODO
             end
         until nestDepth == -1 -- expr is terminated with an END opcode which isn't part of any control flow structure,
                               -- therefore the nestDepth should end up at -1
+        self.functions[i].body = body
     end
 
     return idx
 end
 
-function wasmlib.VM:parseData(bytes, idx) -- TODO
+function wasmlib.VM:parseData(bytes, idx)
     local szlen, _ = intutil.fromuleb128(bytes, idx)
     idx = idx + szlen
     local ndlen, numData = intutil.fromuleb128(bytes, idx)
@@ -844,7 +889,9 @@ function wasmlib.VM:parseData(bytes, idx) -- TODO
     return idx
 end
 
-function wasmlib.VM:instantiate(bytes)
+function wasmlib.VM:instantiate(bytes, imports)
+    self.imports = imports or {}
+
     local idx = 1
     idx = checkMagic(bytes, idx)
     idx = checkVersion(bytes, idx)
@@ -872,12 +919,12 @@ function wasmlib.VM:instantiate(bytes)
         if sectParser == nil then
             error("unsupported section type " .. sectId)
         end
-        idx = sectParser(self, bytes, idx)
+        idx = sectParser(self, bytes, idx, imports)
     end
 end
 
-function wasmlib.VM:instantiateFile(path)
-    self:instantiate(fileutil.readBytes(path))
+function wasmlib.VM:instantiateFile(path, imports)
+    self:instantiate(fileutil.readBytes(path), imports)
 end
 
 return wasmlib
\ No newline at end of file