March 2018
Beginner to intermediate
656 pages
20h 9m
English
Content preview from Mastering Blockchain - Second Edition
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Logging operations
Logging operations provide opcodes to append log entries on the substate tuple's log series field. There are four log operations available in total, and they range from value 0x0a to 0xa4.
|
Mnemonic |
Value |
POP |
PUSH |
Gas |
Description |
|
LOG0 . . . LOG4 |
0x0a ...0xa4 |
X |
Y (0) |
375, 750, 1125, 1500, 1875 |
Used to append log record with N topics, where N is the number corresponding to the LOG opcode used. For example, LOG0 means a log record with no topics, and LOG4 means a log record with four topics. X and Y represent the items removed and placed on the stack, respectively. X and Y change incrementally, starting from 2, 0 up to 6, 0 according to the LOG operation used. |