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authorAnurag Dashputre <anurag4u80@gmail.com>2018-08-23 14:26:45 +0800
committerGitHub <noreply@github.com>2018-08-23 14:26:45 +0800
commit8497dcd721ff0a113374c0c1e1778d44265398a6 (patch)
tree2833ab7b3c7513647c0476d0e5d33dc11fcd6951 /docs/assembly.rst
parent55524788e2829b3a2b9c6c513f78ba2074aa3385 (diff)
parent410d288dfc2e08c42df58c7e01ad5c332ce92727 (diff)
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Merge branch 'develop' into anurag_issue_3667
Diffstat (limited to 'docs/assembly.rst')
-rw-r--r--docs/assembly.rst18
1 files changed, 4 insertions, 14 deletions
diff --git a/docs/assembly.rst b/docs/assembly.rst
index 91ba076a..2cbad06f 100644
--- a/docs/assembly.rst
+++ b/docs/assembly.rst
@@ -82,7 +82,7 @@ you really know what you are doing.
library VectorSum {
// This function is less efficient because the optimizer currently fails to
// remove the bounds checks in array access.
- function sumSolidity(uint[] memory _data) public view returns (uint o_sum) {
+ function sumSolidity(uint[] memory _data) public pure returns (uint o_sum) {
for (uint i = 0; i < _data.length; ++i)
o_sum += _data[i];
}
@@ -90,7 +90,7 @@ you really know what you are doing.
// We know that we only access the array in bounds, so we can avoid the check.
// 0x20 needs to be added to an array because the first slot contains the
// array length.
- function sumAsm(uint[] memory _data) public view returns (uint o_sum) {
+ function sumAsm(uint[] memory _data) public pure returns (uint o_sum) {
for (uint i = 0; i < _data.length; ++i) {
assembly {
o_sum := add(o_sum, mload(add(add(_data, 0x20), mul(i, 0x20))))
@@ -99,7 +99,7 @@ you really know what you are doing.
}
// Same as above, but accomplish the entire code within inline assembly.
- function sumPureAsm(uint[] memory _data) public view returns (uint o_sum) {
+ function sumPureAsm(uint[] memory _data) public pure returns (uint o_sum) {
assembly {
// Load the length (first 32 bytes)
let len := mload(_data)
@@ -378,23 +378,13 @@ used ``x_slot`` and to retrieve the byte-offset you used ``x_offset``.
In assignments (see below), we can even use local Solidity variables to assign to.
-Functions external to inline assembly can also be accessed: The assembly will
-push their entry label (with virtual function resolution applied). The calling semantics
-in solidity are:
-
- - the caller pushes ``return label``, ``arg1``, ``arg2``, ..., ``argn``
- - the call returns with ``ret1``, ``ret2``, ..., ``retm``
-
-This feature is still a bit cumbersome to use, because the stack offset essentially
-changes during the call, and thus references to local variables will be wrong.
-
.. code::
pragma solidity ^0.4.11;
contract C {
uint b;
- function f(uint x) public returns (uint r) {
+ function f(uint x) public view returns (uint r) {
assembly {
r := mul(x, sload(b_slot)) // ignore the offset, we know it is zero
}