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| author | obscuren <geffobscura@gmail.com> | 2014-11-01 09:14:55 +0800 |
|---|---|---|
| committer | obscuren <geffobscura@gmail.com> | 2014-11-01 09:14:55 +0800 |
| commit | 3f90f7c89856f5d024eec1df535a4fc2871214c2 (patch) | |
| tree | 8513bddf2539b6dfadca894092449abdbcd623a8 | |
| parent | c8438979a9c5c73bf68a132d5fd0325863ab454b (diff) | |
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Signextend
| -rw-r--r-- | ethutil/big.go | 4 | ||||
| -rw-r--r-- | vm/vm_debug.go | 14 |
2 files changed, 18 insertions, 0 deletions
diff --git a/ethutil/big.go b/ethutil/big.go index bdcf86421..8d7b3fe70 100644 --- a/ethutil/big.go +++ b/ethutil/big.go @@ -34,6 +34,10 @@ func BigD(data []byte) *big.Int { return n } +func BitTest(num *big.Int, i int) bool { + return num.Bit(i) > 0 +} + // To256 // // "cast" the big int to a 256 big int (i.e., limit to) diff --git a/vm/vm_debug.go b/vm/vm_debug.go index 0abfa098d..129ea1a59 100644 --- a/vm/vm_debug.go +++ b/vm/vm_debug.go @@ -392,6 +392,20 @@ func (self *DebugVm) RunClosure(closure *Closure) (ret []byte, err error) { self.Printf(" = %v", base) stack.Push(base) + case SIGNEXTEND: + back := stack.Pop().Uint64() + if back.Cmp(big.NewInt(31)) < 0 { + bit := uint(back*8 + 7) + num := stack.Pop() + mask := new(big.Int).Lsh(ethutil.Big1, bit) + mask.Sub(mask, ethutil.Big1) + if ethutil.BitTest(num, int(bit)) { + num.Or(num, mask.Not(mask)) + } else { + num.And(num, mask) + } + stack.Push(num) + } case NOT: base.Sub(Pow256, stack.Pop()).Sub(base, ethutil.Big1) |