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core/vm: polish gas PR, fix tests, make table driven

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This commit is contained in:
Péter Szilágyi
2019-04-01 14:56:43 +03:00
parent 157f09e5b6
commit 9294b8f10f
2 changed files with 20 additions and 21 deletions
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14
core/vm/gas_table.go
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@ -25,21 +25,17 @@ import (
// memoryGasCost calculates the quadratic gas for memory expansion. It does so
// only for the memory region that is expanded, not the total memory.
func memoryGasCost(mem *Memory, newMemSize uint64) (uint64, error) {
if newMemSize == 0 {
return 0, nil
}
// The maximum that will fit in a uint64 is max_word_count - 1
// anything above that will result in an overflow.
// Additionally, a newMemSize which results in a
// newMemSizeWords larger than 0xFFFFFFFF will cause the square operation
// to overflow.
// The constant 0x1FFFFFFFE0 is the highest number that can be used without
// overflowing the gas calculation
// The maximum that will fit in a uint64 is max_word_count - 1. Anything above
// that will result in an overflow. Additionally, a newMemSize which results in
// a newMemSizeWords larger than 0xFFFFFFFF will cause the square operation to
// overflow. The constant 0x1FFFFFFFE0 is the highest number that can be used
// without overflowing the gas calculation.
if newMemSize > 0x1FFFFFFFE0 {
return 0, errGasUintOverflow
}
newMemSizeWords := toWordSize(newMemSize)
newMemSize = newMemSizeWords * 32