diff --git a/README.md b/README.md
index 5ec890b..f6517ad 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,10 @@
 
 An assembler for the MIPS R4300i architecture, written in Lua.
 
+This is not a 'true' assembler; it won't produce executable binary files.
+This was intended to assist in hacking N64 games.
+It does little more than output hex.
+
 Not for production. Much of the code and syntax is untested and likely to change.
 Even this README is incomplete.
 
@@ -37,11 +41,16 @@ Instructions were primarily referenced from [the N64 Toolkit: Opcodes.][n64op]
 A more in-depth look at instructions for MIPS IV processors in general
 is given by [the MIPS IV Instruction Set manual.][mipsiv]
 
+[The MIPS64 Instruction Set manual][mips64] is sometimes useful.
+Much of it doesn't apply to our older MIPS IV architecture,
+but it's a little cleaner than the older manual.
+
 There's also a brief and incomplete [overview of MIPS instructions.][overview]
 First-time writers of MIPS assembly may find this the most useful.
 
 [n64op]: https://github.com/mikeryan/n64dev/tree/master/docs/n64ops
 [mipsiv]: http://www.cs.cmu.edu/afs/cs/academic/class/15740-f97/public/doc/mips-isa.pdf
+[mips64]: http://scc.ustc.edu.cn/zlsc/lxwycj/200910/W020100308600769158777.pdf
 [overview]: http://www.mrc.uidaho.edu/mrc/people/jff/digital/MIPSir.html
 
 ### Unimplemented
diff --git a/lips.lua b/lips.lua
index ac76e0d..497218f 100644
--- a/lips.lua
+++ b/lips.lua
@@ -982,7 +982,8 @@ function Parser:instruction()
         local im = self:const()
 
         local is_label = im[1] == 'LABELSYM'
-        -- this is really just semantics as far as i can tell
+        -- for us, this is just semantics. for a "real" assembler,
+        -- LA could add an appropriate RELO directive.
         if h == 'LI' and is_label then
             self:error('use LA for labels')
         end