Tweak doc

document/core/appendix/implementation.rst

diff --git a/document/core/appendix/implementation.rst b/document/core/appendix/implementation.rst
index 15fe693..43baa84 100644
--- a/document/core/appendix/implementation.rst
+++ b/document/core/appendix/implementation.rst
@@ -110,7 +110,7 @@
 Validation
 ~~~~~~~~~~
 
-An implementation may defer :ref:`validation <valid>` of individual :ref:`functions <syntax-func>` until they are first :ref:`invoked <exec-invoke>`.
+An implementation may defer :ref:`validation <valid>` of individual :ref:`functions <syntax-func>` until they are first :ref:`called <exec-call_addr>`.
 
 If a function turns out to be invalid, then the invocation, and every consecutive call to the same function, results in a :ref:`trap <trap>`.
 

document/core/exec/instructions.rst

diff --git a/document/core/exec/instructions.rst b/document/core/exec/instructions.rst
index 652c31c..a98869b 100644
--- a/document/core/exec/instructions.rst
+++ b/document/core/exec/instructions.rst
@@ -141,9 +141,6 @@
 
 .. _exec-call_ref:
 
-:math:`\CALLREF~x`
-..................
-
 $${rule-prose: Step_read/call_ref}
 
 $${rule: {Step_read/call_ref-*}}
@@ -255,7 +252,8 @@
 Exception Handling
 ~~~~~~~~~~~~~~~~~~
 
-The following auxiliary rules define the semantics of entering and exiting ${:TRY_TABLE} blocks.
+The following auxiliary rules define the semantics of entering and exiting ${:TRY_TABLE} blocks,
+and of throwing exceptions.
 
 .. _exec-handler-enter:
 
@@ -298,6 +296,16 @@
 $${rule: Step_pure/handler-vals}
 
 
+.. _exec-throw_addr:
+
+Throwing an exception
+.....................
+
+$${rule-prose: Step_read/throw_addr}
+
+$${rule: Step_read/throw_addr-*}
+
+
 .. index:: ! call, function, function instance, label, frame
 
 Function Calls
@@ -1145,4 +1153,4 @@
 
 .. note::
    Evaluation iterates this reduction rule until reaching a value.
-   Expressions constituting :ref:`function <syntax-func>` bodies are executed during function :ref:`invocation <exec-invoke>`.
+   Expressions constituting :ref:`function <syntax-func>` bodies are executed during function :ref:`calls <exec-call_addr>`.