separate out a new "Design Criteria" section from "Formal Specification"

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Li Xuanji 2018-09-24 16:38:16 -04:00 committed by chriseth
parent 3eb5ecdf58
commit 26d36e1faa

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@ -102,18 +102,19 @@ them.
|:ref:`struct<structs>` |``tuple`` |
+-------------------------------+-----------------------------------------------------------------------------+
Formal Specification of the Encoding
====================================
Design Criteria for the Encoding
================================
We will now formally specify the encoding, such that it will have the following
properties, which are especially useful if some arguments are nested arrays:
Properties:
The encoding is designed to have the following properties, which are especially useful if some arguments are nested arrays:
1. The number of reads necessary to access a value is at most the depth of the value inside the argument array structure, i.e. four reads are needed to retrieve ``a_i[k][l][r]``. In a previous version of the ABI, the number of reads scaled linearly with the total number of dynamic parameters in the worst case.
2. The data of a variable or array element is not interleaved with other data and it is relocatable, i.e. it only uses relative "addresses"
Formal Specification of the Encoding
====================================
We distinguish static and dynamic types. Static types are encoded in-place and dynamic types are encoded at a separately allocated location after the current block.
**Definition:** The following types are called "dynamic":