diff --git a/docs/assembly.rst b/docs/assembly.rst index 2f5b88124..5288089f2 100644 --- a/docs/assembly.rst +++ b/docs/assembly.rst @@ -96,6 +96,29 @@ you really know what you are doing. } } } + + // Same as above, but accomplish the entire code within inline assembly. + function sumPureAsm(uint[] _data) returns (uint o_sum) { + assembly { + // Load the length (first 32 bytes) + let len := mload(_data) + + // Skip over the length field. + _data := add(_data, 0x20) + + // Set up a bound. + let end := add(_data, len) + + // Iterate until the bound is not met. + for {} lt(_data, end) {} { + o_sum := add(o_sum, mload(_data)) + _data := add(_data, 0x20) + } + + // NOTE: after this point it is not safe to use _data in Solidity code + // because its offsets are in an invalid position + } + } }