diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/assembly.rst | 5 | ||||
| -rw-r--r-- | docs/contributing.rst | 4 | ||||
| -rw-r--r-- | docs/introduction-to-smart-contracts.rst | 8 | ||||
| -rw-r--r-- | docs/miscellaneous.rst | 11 |
4 files changed, 21 insertions, 7 deletions
diff --git a/docs/assembly.rst b/docs/assembly.rst index cf9bf840..705cd1b8 100644 --- a/docs/assembly.rst +++ b/docs/assembly.rst @@ -647,6 +647,11 @@ Solidity manages memory in a very simple way: There is a "free memory pointer" at position ``0x40`` in memory. If you want to allocate memory, just use the memory from that point on and update the pointer accordingly. +The first 64 bytes of memory can be used as "scratch space" for short-term +allocation. The 32 bytes after the free memory pointer (i.e. starting at ``0x60``) +is meant to be zero permanently and is used as the initial value for +empty dynamic memory arrays. + Elements in memory arrays in Solidity always occupy multiples of 32 bytes (yes, this is even true for ``byte[]``, but not for ``bytes`` and ``string``). Multi-dimensional memory arrays are pointers to memory arrays. The length of a dynamic array is stored at the diff --git a/docs/contributing.rst b/docs/contributing.rst index 1bcaed7c..7c199d53 100644 --- a/docs/contributing.rst +++ b/docs/contributing.rst @@ -55,8 +55,8 @@ However, if you are making a larger change, please consult with the `Solidity De focused on compiler and language development instead of language use) first. -Finally, please make sure you respect the `coding standards -<https://raw.githubusercontent.com/ethereum/cpp-ethereum/develop/CodingStandards.txt>`_ +Finally, please make sure you respect the `coding style +<https://raw.githubusercontent.com/ethereum/solidity/develop/CODING_STYLE.md>`_ for this project. Also, even though we do CI testing, please test your code and ensure that it builds locally before submitting a pull request. diff --git a/docs/introduction-to-smart-contracts.rst b/docs/introduction-to-smart-contracts.rst index 56f0fe3e..84b1fff8 100644 --- a/docs/introduction-to-smart-contracts.rst +++ b/docs/introduction-to-smart-contracts.rst @@ -326,7 +326,13 @@ EVM bytecode and executed. The output of this execution is permanently stored as the code of the contract. This means that in order to create a contract, you do not send the actual code of the contract, but in fact code that -returns that code. +returns that code when executed. + +.. note:: + While a contract is being created, its code is still empty. + Because of that, you should not call back into the + contract under construction until its constructor has + finished executing. .. index:: ! gas, ! gas price diff --git a/docs/miscellaneous.rst b/docs/miscellaneous.rst index 01154854..20400aa2 100644 --- a/docs/miscellaneous.rst +++ b/docs/miscellaneous.rst @@ -64,12 +64,15 @@ The position of ``data[4][9].b`` is at ``keccak256(uint256(9) . keccak256(uint25 Layout in Memory **************** -Solidity reserves three 256-bit slots: +Solidity reserves four 32 byte slots: -- 0 - 64: scratch space for hashing methods -- 64 - 96: currently allocated memory size (aka. free memory pointer) +- ``0x00`` - ``0x3f``: scratch space for hashing methods +- ``0x40`` - ``0x5f``: currently allocated memory size (aka. free memory pointer) +- ``0x60`` - ``0x7f``: zero slot -Scratch space can be used between statements (ie. within inline assembly). +Scratch space can be used between statements (ie. within inline assembly). The zero slot +is used as initial value for dynamic memory arrays and should never be written to +(the free memory pointer points to ``0x80`` initially). Solidity always places new objects at the free memory pointer and memory is never freed (this might change in the future). |