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| author | Alex Beregszaszi <alex@rtfs.hu> | 2016-10-11 19:25:18 +0800 |
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| committer | Alex Beregszaszi <alex@rtfs.hu> | 2016-10-11 20:20:58 +0800 |
| commit | f0524ed45a407ff9b1b59ee04edbfb9489a4f8a1 (patch) | |
| tree | 377b6466b2e4dec54a24300185ba86a965016c5f /docs/miscellaneous.rst | |
| parent | d3f410d8a89aaa042ff264d7a0ea79184e01abab (diff) | |
| download | dexon-solidity-f0524ed45a407ff9b1b59ee04edbfb9489a4f8a1.tar.gz dexon-solidity-f0524ed45a407ff9b1b59ee04edbfb9489a4f8a1.tar.zst dexon-solidity-f0524ed45a407ff9b1b59ee04edbfb9489a4f8a1.zip | |
Document memory layout
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| -rw-r--r-- | docs/miscellaneous.rst | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/docs/miscellaneous.rst b/docs/miscellaneous.rst index c4a954ad..cdc82c78 100644 --- a/docs/miscellaneous.rst +++ b/docs/miscellaneous.rst @@ -56,6 +56,20 @@ So for the following contract snippet:: The position of ``data[4][9].b`` is at ``keccak256(uint256(9) . keccak256(uint256(4) . uint256(1))) + 1``. +**************** +Layout in Memory +**************** + +EVM memory is linear. Reading is limited to 256-bit width, but both 8-bit and 256-bit writes are allowed. Memory size is 0 at the beginning of execution. Memory is expanded by accessing (either reading or writing) a previously untouched memory offset. At the time of expansion, the cost in gas must be paid. + +Solidity reserves three 256-bit slots: +- 0 - 64: scratch space for hashing methods +- 64 - 96: currently allocated memory size (aka. free memory pointer) + +Solidity always places new objects at the free memory pointer and memory is never freed. + +.. index: memory layout + ***************** Esoteric Features ***************** |