cerc-io/solidity
11
0
Fork 0
mirror of https://github.com/ethereum/solidity synced 2023-10-03 13:03:40 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Correctly use not/bnot/iszero.

Browse Source 
A long time ago, some opcodes were renamed. Now we should only have
not (bitwise negation) and iszero (logical negation).
This commit is contained in:
chriseth
2016-05-09 10:52:23 +02:00
parent 9e36bdda8a
commit a927efb151
3 changed files with 25 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files
docs/control-structures.rst
+3 -3
View File
@@ -208,7 +208,7 @@ idea is that assembly libraries will be used to enhance the language in such way
// by using o_code = new bytes(size)
o_code := mload(0x40)
// new "memory end" including padding
mstore(0x40, add(o_code, and(add(add(size, 0x20), 0x1f), bnot(0x1f))))
mstore(0x40, add(o_code, and(add(add(size, 0x20), 0x1f), not(0x1f))))
// store length in memory
mstore(o_code, size)
// actually retrieve the code, this needs assembly
@@ -292,7 +292,7 @@ The opcodes `pushi` and `jumpdest` cannot be used directly.
+-----------------------+------+---------------------------------------------------------------+
| exp(x, y) | | x to the power of y |
+-----------------------+------+---------------------------------------------------------------+
| bnot(x) | | ~x, every bit of x is negated |
| not(x) | | ~x, every bit of x is negated |
+-----------------------+------+---------------------------------------------------------------+
| lt(x, y) | | 1 if x < y, 0 otherwise |
+-----------------------+------+---------------------------------------------------------------+
@@ -304,7 +304,7 @@ The opcodes `pushi` and `jumpdest` cannot be used directly.
+-----------------------+------+---------------------------------------------------------------+
| eq(x, y) | | 1 if x == y, 0 otherwise |
+-----------------------+------+---------------------------------------------------------------+
| not(x) | | 1 if x == 0, 0 otherwise |
| iszero(x) | | 1 if x == 0, 0 otherwise |
+-----------------------+------+---------------------------------------------------------------+
| and(x, y) | | bitwise and of x and y |
+-----------------------+------+---------------------------------------------------------------+